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ultra-compact silicon mode (de)multiplexers are demonstrated based on asymmetric directional couplers with subwavelength structure (ADCWSS), the subwavelength structure is a series of corrugation on the sidewalls of waveguides, and the two arrays of corrugation extend into the gap region between the waveguides and interlace with each other. The coupling length of ADCWSS are 5.6μm, 6.5μm, and 7.9μm for TE0-TE1, TE0-TE2, TE0-TE3 mode (de)multiplexers, respectively. The four-mode mode-division-multiplexing (MDM) link was fabricated and measured. The insertion losses of TE0-TE0-TE0, TE0-TE1-TE0, TE0-TE2-TE0, and TE0-TE3-TE0 are 0.2dB, 0.7dB, 0.7dB and 0.9dB (around 1.55μm). The maximum insertion losses and crosstalk are 2.4dB, 2.9dB, 3.0dB, 4.0dB and -18dB, -19dB, -16dB, -18dB for the TE0, TE1, TE2 and TE3-mode channels over a 50-nm bandwidth.

An athermal, fabrication-tolerant and flat-topped 4-channel coarse wavelength-division multiplexing(CWDM) (de)multiplexer based on cascaded Mach-Zehnder interferometers (MZIs) was proposed in this paper. A combination of strip waveguide and slot waveguide is utilized for athermalization and flat-topped transmission. By optimizing the waveguide widths and lengths of two arms in each MZI, the influence of temperature and waveguide broadening can be compensated. The best temperature dependent center wavelength shift of the four channels is about 12 pm/K, and the best waveguide broadening dependent center wavelength shift is about 0.06nm/nm, while the 1- and 3-dB bandwidths are ~14nm and ~19nm with 20nm free spectral range (FSR) and the crosstalk is < −20dB at center wavelength by utilized the power splitters based on the bend directional couplers.

Wavelength-swept laser is one of the most critical common components of fiber Bragg grating (FBG) sensors. However, a fast, stable, integrated and low-cost multi-channel wavelength-swept laser array is still unavailable. In this article, a multi-channel simultaneous wavelength-swept DFB laser array based on the reconstruction-equivalent-chirp (REC) technique is proposed and manufactured. The REC technology simplifies the fabrication process and greatly reduces the cost of the laser. The laser array contains 4 lasers in parallel with integrated heating resistance for thermal tuning to broaden the wavelength-tuning range. Each single-wavelength DFB laser introduces a π-phase shift structure, which is used to improve the single-mode performance of the laser. Meanwhile, the active multiplexer responsible for coupling and an optical amplifier (SOA) responsible for compensating the coupling loss of the laser are also integrated on the same chip. The driving circuits of the laser use FPGA to control the DAC chip to obtain precise current output and realizes continuous linear output of wavelength by changing the injection current size. The packaged laser module can realize a continuous wavelength-swept range of 2.4 nm per channel with the SMSR over 40 dB, achieving a simultaneous sweep of four channels with good scanning linearity and scanning speed. The work of this paper realizes the integration of linear wavelength-swept light sources, which creates the conditions for a low-cost, small-volume multi-channel sensing system in the future.

An experimental demonstration of laser beam coherent combining with active phase control has been performed using for the first time a Multi-Plane Light Converter device (MPLC). The MPLC as a beam combiner is designed as a spatial multiplexer which output modes form a Gaussian beam when superimposed constructively, reaching theoretically 100% efficiency. Moreover, reflective free-space design allows for handling high power. The experiment combines seven 1.5 μm continuous wave fiber lasers operated at a low power level in the tens of milliwatt range using the frequencytagging LOCSET technique (Locking of Optical Coherence by Single-detector Electronic-frequency Tagging) for the phase locking. 72-% power efficiency MPLC CBC is achieved with an output combined beam close to a Gaussian beam profile. M² is lower than 1.8 depending on the transverse direction, revealing an excellent quality for the combined beam. The output beam is more than 94 % linearly polarized. Simulation of the impact of atmospheric turbulence on the propagation of the seven laser beams up to 1 km is performed. We demonstrate that it is possible to compensate for most of the atmospheric propagation detrimental effects and to perform efficient MPLC CBC through strong turbulence.

The seamless integration of electronics with biology requires new bio-inspired approaches that, analogously to nature, rely on the presence of electrolytes for signal multiplexing. On the contrary, conventional multiplexing schemes mostly rely on electronic carriers and require peripheral circuitry for their implementation, which imposes limitations toward their adoption in bio-applications. Here we show an iontronic multiplexer based on spatiotemporal dynamics of organic electrochemical transistors (OECTs), with an electrolyte as the shared medium of communication. The iontronic system discriminates locally random-access events with no need of peripheral circuitry, thus deceasing significantly the integration complexity. The form factors of OETCs, open new avenues for unconventional multiplexing in the emerging fields of bioelectronics and neuromorphic sensors. Examples of organic neuromorphic electronics for local learning in applications with energy restrictions are also showcased.

High capacity throughputs are more and more requested by satellite owners, even before launching the first generation of optical constellations. MPB is developing a commercially-competitive photonics subsystem that increases the data throughput of a “free-space” optical link in a space environment. The objective is to build and demonstrate an optical subsystem suitable for deployment in space with a target capacity of ≥100Gbit/s having a scalable architecture optimized for cost per Gbit, while maintaining acceptable (e.g. 10-4) pre-FEC bit error ratio (BER), high reliability, design flexibility. The two most promising solutions for the 100Gbps links use either a suitably-adapted commercial 100 Gbps x 1ch transceiver (e.g. commercial Dual-Pol 28Gbaud, 4 bits/symbol) or wavelength-agile WDM 10 Gbps x 10ch, or similar system (e.g. 12.5 Gbps x 8ch). The subsystem is based on the selected optimal architecture, convenient for space environment, and potentially comprising one or more of the “throughput-enhancing” possible approaches; such as the Modulation bitrate, Wavelength multiplexing (WDM), and Spectral efficiency. A large number of the performance parameters are also involved in the evaluation of the optimal solution, including: OSNR, Power at Rx, Mass and Volume, Cost, Complexity of the Software and Hardware to develop, Reliability/Redundancy, Power-Consumption and wall-plug Efficiency (W/Gbps), Signal Modulation, BER, and Stimulated Brillouin Scattering. MPB plans to verify that the 100G commercial transceiver, a coherent module optimized for terrestrial use, is compatible with the harsh space environment. Moreover, its design needs to be modified (in collaboration with the manufacturer) in order to employ distinct Tx and Rx wavelengths. Although such an approach enables all data to be sent over a single wavelength, in the event of an e.g. Tx optical-amplifier failure all transmission capability would be lost. The coherent transceivers themselves are very complicated in design, but this development has already been carried out by the manufacturer for terrestrial applications. The WDM option 10 G x 10ch has a larger mass, volume, and power per Gbps, however, the technology is based on MPB-developed boosters for space applications and offers higher redundancy (i.e. if one optical Tx amp fails, the other nine channels can still transmit). This option adds more complexity and cost since it needs to develop more software and hardware items. This development is useful for the other amplifiers with similar requirements from space primes. In addition, we are including a detailed study and prototyping of a space-borne Reconfigurable Optical Add-Drop Multiplexer (ROADM), which would enable greatly enhanced dynamic bandwidth allocation. The two approaches (single-channel high BW vs multi-channel medium BW) have respective advantages and disadvantages.

The ultra-wideband multiplexed synthesis technology can first filter microwave signals of different frequency bands, filter out the clutter and then synthesize the frequency and power, and the synthesized wideband signal can be used for the reception and processing of communication satellites, and the wider signal can carry more information, which greatly enhances the communication capability of satellites and saves costs. In this paper, we introduce the development status of ultra-wideband multiplex synthesis technology and give several application scenarios.

One of the common methods to increase data bitrate using visible light communication (VLC) fibers system is to use wavelength division multiplexing (WDM). However, the implementation of WDM requires additional components and more energy consumption which can limit the system performances. To overcome these issues, we propose a new method for designing an RGB multiplexer based on multicore polymer optical fiber (MC-POF). The new design is based on replacing seven air-holes areas with polycarbonate (PC) layers along the fiber length. The PC layer length sizes are suitable to the light coupling of the operating wavelengths which allows us to control the light switching between closer PC layers and to obtain an RGB multiplexer device without adding more devices. Results show that after a 20 mm light propagation the PC MC-POF RGB multiplexer can be obtained with a low power loss of 0.6 to 1.02 dB, large bandwidth of 7.3 to 28.4 nm and good isolation between the transmission of the input RGB channels.

The large mode size mismatch between standard single-mode optical fibers and silicon-on-insulator (SOI) waveguides poses a significant challenge to efficiently couple light from the optical fiber to the chip, and vice versa. Surface grating couplers are often used for this purpose, however, their operational bandwidth is limited to a few tens of nanometers, as a consequence of the wavelength-dependent radiation angle. This constraint seriously hampers the use of surface grating couplers for next-generation passive optical networks (PONs), in which the wavelengths used for the upstream and downstream channels are separated more than 150 nm. In this work, we present a dual-band grating coupler for 10 Gbit symmetric PONs. Our device operates as a wavelength multiplexer/demultiplexer, simultaneously coupling and combining/splitting two optical signals at the wavelengths of λ_1=1270 nm and λ_2=1577 nm. The coupler is based on engineering a surface grating coupler to obtain opposite radiation angles for the two respective wavelengths. To achieve a higher coupling efficiency, the material platform thicknesses were optimized as a tradeoff between the waveguide propagation loss and the substrate reflectivity. By judiciously choosing the period (Λ=500 nm) and the duty cycle (DC=55%) of the grating section, an efficient dual-band grating coupler is designed with a minimum feature size of 225 nm. The coupler was fabricated in ST Crolles using their 300 mm SOI platform and 193-nm deep-ultraviolet lithography, demonstrating that large-scale fabrication is feasible. Measured fiber-chip coupling efficiencies were -4.9 dB and -5.2 dB with a 3-dB bandwidth of >27 nm and 56 nm at λ_1=1270 nm and λ_2=1577 nm, respectively.

Electrical impedance tomography (EIT) is a rising and emerging imaging technique with great potential in many areas, especially in functional brain imaging applications. An EIT system with high speed and accuracy can have many applications to medical devices supporting in diagnosis and treatment of neurological disorders and diseases. In this research, EIT algorithms and hardware are developed and improved to increase reconstructed images' accuracy and decrease the reconstruction time. Due to multiplexer design limitations, EIT measurements are subject to strong capacitive effects from charging and discharging in switching cycles around 300 to 400 samples per 1280 samples (in 10 milliseconds sampling). We developed an algorithm to choose data in steady-state condition only selectively. This method improves the signal-to-noise ratio and results in better reconstruction images. An algorithm to effectively synchronize the beginning points of data was developed to increase the system's speed. This presentation also presents the EIT system's hardware architecture based on Texas Instruments Fixed-Point Digital Signal Processor - TMS320VC5509A, which is low-cost, high potential in popularity the community in the future. For high operation speed, we propose the EIT system used Sitara™ AM57x processors of Texas Instruments.

In healthcare products the proper fit of e.g. orthosis is crucial for its therapeutic success. To monitor movement and pressure, sensors with the ability to adapt their shape to the curvilinear form of the human body as well as a highly dynamic performance during motion are needed. Dielectric elastomer sensors (DES) present most of the required specifications and can be an excellent solution for body-near motion detection. For signal capturing either changes in resistance, capacitance or impedance can be measured. Therefore, different circuit configurations can be used that follow different methods e.g. frequency based or an impedance approach. In this paper, an impedance measurement bridge that enables the detection of stretch and pressure loads with a frequency of 200 Hz is modified. The novel architecture is conceptualized to work with a battery based energy supply and have small enough dimensions to function as a wearable with a wireless communication interface. Furthermore, our former presented additive manufacturing method for dielectric elastomers via aerosol jet printing allows an integrated tuning of the measurement bridge in the process. In addition, to the electrodes of the capacitor one electrode with a defined layer resistance is stacked on top of the DES. Hence, the additional electrode, which makes the architecture scalable for different sensor sizes and shapes, serves as an integrated adjustment of the measurement bridge. The data acquisition of multiple sensors is feasible by time division multiplexing, but is limited in its frequency due to the switching rate of the multiplexer.

This paper uses the concept of request/response for the management of a trajectory in a two-way-two-way traffic lights controlled crossroad, using Visible Light Communication (VLC). The connected vehicles receive information from the network (I2V), interact with each other (V2V) and with the infrastructure (V2I), using a request distance and pose estimation concept. In parallel, an intersection manager (IM) coordinates the crossroad and interacts with the vehicles (I2V) using the response distance and the pose estimation concepts. The communication is performed through VLC using the street lamps and the traffic signaling to broadcast the information. Data is encoded, modulated and converted into light signals emitted by the transmitters. Tetra-chromatic white sources are used providing a different data channel for each chip. As receivers and decoders, SiC Wavelength Division Multiplexer (WDM) devices, with light filtering properties, are used. A simulated Vehicle-to-Everything (V2X) traffic scenario is presented and a generic model of cooperative transmission established. The primary objective is to control the arrival of vehicles to the intersection and schedule them to cross at times that minimize delays. Bidirectional communication between the vehicles and the infrastructure is tested, using the VLC request/response distance and pose estimation concepts. A phasing traffic flow is developed as a proof of concept. The simulated/experimental results confirm the cooperative VLC architecture. Results show that the communication between connected cars is optimized using a request/response concept and that pose analysis is an important issue to control driver’s behavior in a crossroad. The block diagram conveys that the vehicle’s behavior (successive poses) is influenced by the manoeuvre permission, by the I2V messages and also by the intersection redesigned layout and presence of other vehicles. An increase in the traffic throughput with least dependency on infrastructure is achieved.

Aluminum nitride (AlN), which belongs to the family of the III-V semiconductors, is a material of great interest in the microelectronics industry due to its high decomposition temperature, good chemical stability, wide bandgap and CMOS compatibility. Moreover, AlN is known by its Pockels coefficients, which makes it very suitable for various non-linear optical devices. In this work, a study of a design space exploration of fundamental mode polarization in an AlN pedestal waveguide is proposed. The current work performs a dispersion analysis of this type of waveguide by varying the dimensions of the core and the pedestal. Lastly, electrode design for phase shifting analysis is also proposed. The data obtained with the exhibited work will allow the device designer to have a design space with light polarization control to stimulate the adequate electro-optic coefficient, with potential applications in modulators, switches, multiplexers, phase shifters, among others. A feasibility study will also be provided.

Multimode silicon photonics have drawn tremendous attention because the introduction of higher-order modes greatly enhances the capacity of mode-division-multiplexing (MDM) data transmission systems as well as improves the flexibility of on-chip photonic device designs. As the cornerstone of multimode silicon photonics, plentiful multimodemanipulation photonic devices have been developed successfully. On the other hand, more and more emerging applications have been stimulated by higher-order modes introduced in multimode silicon photonics. This paper gives a review for our recent processes in the development of multimode silicon photonic devices. Keywords: mode, multiplexer, conversion, bend, filter, silicon, waveguide.

Silicon photonic switches are recognized as a key element in the applications of telecommunication networks, data center and high-throughput computing due to the low losses, low power consumption, large bandwidth and high integrated density. In this paper our recent works on silicon photonic switches for reconfigurable photonic integrated devices and circuits used in wavelength-division-multiplexing (WDM), mode-division-multiplexing (MDM), as well as hybrid WDM-MDM systems. First, high-performance Mach-Zehnder switches with an ultra-broad bandwidth, polarization-insensitivity, and low phase errors are reviewed. Second, wavelength-selective photonic switches based on MRRs are discussed. Finally, the progresses of multi-channel reconfigurable optical add-drop multiplexers are reviewed.

This paper proposed and demonstrated a novel distributed optical fiber vibration sensor with high sensitivity and high accuracy based on time delay estimation. The light source is divided into two wavelength bands by a wavelength division multiplexer to form two Sagnac interferometers. The dual Sagnac interferometer can detect the interference signals of different bands modulated by the same disturbance, and then obtain the corresponding phase difference by demodulating the interference signals. Based on the time delay estimation algorithm, the phase difference is used to construct two composite signals with time delay, and then the time delay is extracted by cross-correlation to determine the location of vibration. A positioning software is developed based on LabVIEW. Through the vibration simulation experiment driven by piezoelectric transducer (PZT), it is proved that the sensor can realize the disturbance positioning above 400 Hz. The experimental results show that the sensing distance of the sensor can reach 100 km, and the positioning error is within ± 30 m. It can be widely used in long-distance perimeter security

We are developing an x-ray imaging spectrometer for Super DIOS satellite mission, a future x-ray observatory, planned by JAXA, to be launched in 2030’s. Super DIOS will reveal the nature of the missing baryon in the warm-hot intergalactic medium because of its fine energy and angular resolution, large effective area and large field of view. A main detector on-board Super DIOS consists of a transition-edge sensor (TES) microcalorimeter array of over 30,000 pixels working at a temperature below 100 mK and it poses a considerable technical difficulty to the readout. A microwave superconducting quantum interference device (SQUID) multiplexing is promising technique and expected to achieve a large scale readout of more than 30,000 pixels. We describe our development of a 40-channel microwave SQUID multiplexer with low-noise characteristics∗ and a demonstration of simultaneously reading out 40-pixel TESs. Finally, we discuss a future prospect and a feasibility of reading out an array of more than 30,000 pixels.

Kinetic inductance traveling-wave parametric amplifiers (KITs) are under development for the read out of large cryogenic detector arrays. We present new KIT designs based on 20nm NbTiN films patterned by use of standard optical photolithography. We report device gain, bandwidth, and noise properties, which approach the quantum limit. In addition, we demonstrate a KIT preamplifier with a microwave SQUID multiplexer. The improved input referred current noise, as compared to standard HEMT readout, opens up new possibilities for cryogenic receivers. We discuss these benefits.

A high-order mode converter and multiplexer based on silicon waveguide is designed. According to the principle of mode coupling, the conversion between high-order modes in different polarization states can be realized, including TM01 toTE11 mode conversion and TE01 to TM11mode conversion. Using the FDTD method, we analyze in detail the influence of the waveguide width W on the mode refractive index N, as well as the influence of the waveguide width W, the gap G and the coupling length L between different waveguides on the polarization extinction ratio and insertion loss. The results show that the polarization extinction ratio of the designed mode converter is 23.17dB and 24.9dB, the loss is 0.27dB and 0.589dB, and the coupling length is 14µm and 9.7µm, respectively. Besides, we proposed a 10-channel simultaneous polarization and mode division multiplexing system by the cascade of 10 mode converters, which can further increase the communication capacity.

With the vigorous development of data centers, optical fiber interconnection technologies have been evolved from multimode optical fiber (MMF) parallel transmission to CWDM4 single-fiber bidirectional (Bidi) transmission. What’s more, requirements for miniaturization of optical transceivers are put forward. This paper studies a CWDM4 Bidi transceiving module based on hybrid integration technology. Six optical interleavers in serial and parallel connection function as the CWDM4 wavelength division multiplexer and demultiplexer, while an optical circulator is designed with the three inputs/outputs at the same side, which helps to realize Bidi transmission. The former is based on integrated optics and the latter is based on micro-optics. Through the hybrid integration of integrated optics and micro-optics technologies, the transceiving module is minimized and can be integrated into a QSFP module.

With the construction of the new generation of intelligent optical network, the demand for ROADM (Reconfigurable Optical Add-Drop Multiplexer), which is composed of WSS (Wavelength Selective Switch) and MCS (Multicast Switch), is increasing rapidly. Aiming at the 1 × N-channel optical switch, which is the core component of MCS, a technical scheme based on optical waveguide array and MEMS micromirror is proposed in this paper. The optical waveguide array with bending transition part is used as the input / output channel instead of the traditional optical fiber array, which can control the crosstalk and greatly reduce the off-axis amount of the edge channel. At the same time, two collimating lenses are used to further reduce the off-axis aberrations of the edge channels to achieve more output channels.

Compared with the arrayed waveguide grating (AWG) that widely used as optical wavelength multiplexers and/or demultiplexers (MUX/DMUX) in optical communication networks, AWG of low diffraction order has enormous potential of application in cases that need a large free spectrum range (FSR), to name a few, various integrated optical spectrometer, and wavelength MUX/DMUX in coarse wavelength division multiplexing (CWDM) networks. In the current paper, an investigation is conducted on S-shaped antisymmetric design scheme for low diffraction order AWG layouting. To reduce overall AWG device dimension and increase bend waveguide curvature radius uniformity, particle swarm optimization (PSO) with constrained conditions is employed to find optimized geometrical parameters which determine AWG structure. PSO algorithm could reduce by about 50.6% of the AWG dimension compared with previously reported AWG and thus PSO could be a promising optimization method when designing AWG.

To meet the demand for ever-increasing data transfer rates in fiber optic communications, there is great interest in space-division multiplexing of light. Mode-division multiplexing, a subset of space-division multiplexing, increases the channel capacity of a system by spatial conversion and coupling of optical signals into the orthogonal modes of a multimode fiber channel. Current mode multiplexers, which rely on directional couplers, photonic lanterns, and free-space optics, can be challenging to fabricate, align, and scale to a large number of modes with low loss and crosstalk. As a result, more resources have to be spent on amplifiers and digital signal processing which increases the cost of the communications system. Metasurfaces offer a solution to this problem and have shown wide success in realizing various optics. Being lithographically patterned with subwavelength-scale dielectric structures, metasurfaces allow full control of the wavefront. We adopt a folded metasurface configuration by coating the dielectric structures with cladding and depositing metal on both sides of a glass substrate. Inside the substrate, light interacts with the metasurface multiple times to yield unprecedented abilities in shaping light. Based on this platform, we demonstrate a metasurface mode multiplexer design with low loss and crosstalk in the telecom. It directly aligns to an array of input fibers and an output fiber and converts each input mode into the orthogonal modes of the latter fiber. Short-distance and long-haul communication systems such as data centers and submarine links, respectively, can benefit from this mode multiplexer.

Magnetic skyrmions are quasiparticle configurations in a magnetic film that can act as information carrying bits for ultrasmall, low power nonvolatile memory. Skyrmions can be nucleated and driven by spin-orbit torque from a current driven in a heavy metal underlying a ferromagnetic layer, the configuration commonly called a racetrack. Recently it has been shown that by hybridizing the skyrmion between Neel and Bloch types the magnus effect on skyrmion motion, which makes it veer from a straight path down a racetrack, can be effectively canceled which provides them a self-focused naturally converging lane" to travel through. This is achieved by exploiting the voltage controlled magnetic anisotropy effect whereby the magnetic anisotropy of the ferromagnetic racetrack can be positionally modulated by a gate voltage. In this work we show, using detailed micromagnetic simulations, that by using hybrid skyrmions we can obtain demultiplexer functionality out of a racetrack. We further propose a hybrid skyrmionic reconfigureable computing fabric. In conventional CMOS based field programmable gate arrays, SRAM cells are used to build a LUTs storing pre-computed truth-table of a Boolean function and a multiplexer selects one of the storage cells as the output. We show that non-volatile hybrid skyrmions can also act as the memory element and the gateable self-focused nature of the hybrid skyrmions can be exploited to program the proposed CMOS-skyrmion hybrid design to perform different logic operations. The low driving energy and non-volatility of magnetic skyrmion in a racetrack promises the development of energy efficient programmable architecture for future system-on-a-Chip (SoC) designs.

In this paper, we propose the option of constructing a multi-channel system of quantum key distribution with frequency coding based on the AMPM-PMAM electro-optical scheme, using a Comb generator, multiplexer and demultiplexer to form a set of parallel quantum subchannels. The AMPM-PMAM work of the QKD system is based on the modulation conversion of the photon carrier based on the Ilyin-Morozov method and its one- and two-modulator implementations. The application of this scheme will significantly increase the transmission speed of the quantum key, allow the use of several levels of cryptographic protection, reduce the likelihood of achieving a positive result in PNS attacks of Eve (illegal subscriber) by eliminating the carrier from the structure of the signal transmitted through the quantum key distribution channel, and splitting information about key to different independent quantum channels.

Based on an integrated silicon platform, we propose a device for generating and multiplexing optical orbital angular momentum modes(OAM), which is consisted of asymmetric directional couplers and trench waveguides. Asymmetric directional coupler is composed of single-mode and multi-mode waveguides . According to the principle of phase matching, the fundamental mode TE00 is coupled to the second-order mode via an asymmetric directional coupler. Single-trench waveguide can support two orthogonal eigenmodes. By adjusting the phase difference of two orthogonal eigenmodes to make them degenerate, they can be converted into orbital angular momentum modes with topological charges of +1, 0, -1, and multiplexed in the second trench. We simulate and analyze the characteristics of the device using three-dimensional finite difference domain method (3D-FDTD). The simulation results show that the device can realize the generation and multiplex of orbital angular momentum modes with topological charges +1, 0, -1. The proposed device is very compact with a footprint of 92 μm×5.3 μm and an insertion loss of 0.359 dB. The structure woks on a wavelength range from 1.48 μm to 1.57 μm. The structure is simple and easy to integrate, having a good application in OAM multiplexing system.

Free-space optical links are being considered for high throughput feeder links in satellite communication. Optical power up to 500 W is required at the optical ground terminal, which represents a challenge for current technologies. One way to scale power whilst preserving beam quality is coherent beam combining. Here, we present a novel technique based on Multi-Plane Light Conversion, consisting in a spatial multiplexer whose output modes form a Gaussian beam when superimposed constructively. The beam combiner is fully reflective, enabling kW optical power. We demonstrate a mode purity and a total efficiency higher than the conventional tiled apertures technique.

Optical satellite communication is growing fast and among various applications it requires higher throughput optical feeder links. Optical feeder links for satellite communication necessitate very high data throughput, up to 1 Terabit/s and beyond. Amongst several multiplexing strategies, dense wavelength division holds a key position to enable overall throughput rates above 1 Terabit/s. As a consequence, hardware architectures capable of handling high throughput links must be devised. Complementary to the high throughput requirement, the devices should also cope with the high optical power levels needed in optical ground stations. Combination of spatial aperture multiplexing and free space bulk optics configurations of multiplexers with transmission defraction gratings are presented as possible concepts. Besides wavelength multiplexing, it is essential to include the beam propagation effects in the performance analysis, since this may effect the overall feeder link properties. A modelling framework is presented that covers the multiplexing behavior as well as the beam propagation of the transmission gratings based concept. The modelling framework based on first principles of optical diffraction is general, and independent of the grating choice. The results suggest that the design of a free space bulk multiplexer for optical feeder link must be approached already at system level. Decisions about telescope sizing, channels distribution and modulation formats may affect the performance of the multiplexer, resulting in severe effects on the link performance. The work discusses the effect on each design parameter and proposes design guidelines for high power satellite communication beam multiplexing.

In this paper, an integrated optical receiver module with demultiplexer chip-to-chip optical interconnects is proposed. The receiver and demultiplexer (demux) were realized on a single chip in a 0.18 μm TSMC CMOS technology. The topology uses a 1:2 for the demux while the receiver (Rx) module consists of transimpedance amplifier (TIA) and a limiting amplifier (LA). The receiver achieved a gain of 90 dBΩ and a 3-dB bandwidth of 4.5 GHz. Clear eye diagrams were observed with a voltage swing of 375 mVpp up to 2.5 Gbps output from the Rx-Demux at 5 Gbps input signal. The integrated chip occupies an area of 594x1089 μm2 with power consumptions of 122 mA under a 1.8 V power supply This solution could be applied to CPU/memory interface where bidirectional signaling is required.

A mature silicon photonics platform including various materials for a wide range of functionalities is needed to achieve high-speed and energy-efficient transceivers for Datacom. We present the latest developments of our 200mm silicon photonics platform including new devices in silicon nitride along with active devices. In particular, we demonstrate a high performance SiN Echelle Grating CWDM (de-)multiplexer obtained with advanced photolithography tools, hybrid Si-SiN polarization splitter rotator, SiN edge coupler and low-loss, low-crosstalk Si-SiN and SiN-SiN crossings.

In this research, we propose a mode selective switch (MSS) using volume holograms. MSS is a device that distributes the mode-division multiplexed (MDM) signal to different output ports for each spatial mode component contained in the signal. Using MSS, the function of reconfigurable optical add / drop multiplexer (ROADM) can be implemented, which can manipulate arbitrary spatial mode signal at any position in the next generation MDM network. In our proposed MSS, the incident signal is separated into spatial mode components by the volume hologram on the input side. The signal destination will be selected for each mode by diffracting independently. The spatial mode components are separated in direction of the plurality of volume holograms on the output side using a spatial light modulator (SLM). In the volume hologram on the output side, the multiple spatial mode components are recombined and emitted once again as an MDM signal. This method has the advantageous that one volume hologram can multiplex or de-multiplex multiple modes, allowing it to cope easily with the increase in the number of modes and ports to be multiplexed. In the experiment, the optical signal lights of three-mode are separated for each spatial mode by the volume hologram on the input side, and the switching to either of the two ports on the output side is successfully performed for each mode using the SLM.

In order to serve the changing needs of road traffic control, the road space and road structure surrounding an intersection have evolved into complex forms. Using a new concept of request/response in a two-way-to-way traffic light controlled crossroad, the redesign of the trajectories can be accomplished by the application of methods for navigation, guidance and combination of expert knowledge of vehicle road traffic control. In this work, the communication between the Infrastructures and the Vehicles (I2V), between vehicles (V2V) and from the Vehicles to the Infrastructures (V2I) is performed through Visible Light Communication (VLC), using the street lamps and the traffic signaling to broadcast the information. Vehicle headlamps are used to transmit data to other vehicles or infrastructures, allowing digital safety and data privacy. Data is encoded, modulated and converted into light signals emitted by the transmitters. Tetra-chromatic white sources are used, providing a different data channel for each chip. As receivers and decoders, SiC Wavelength Division Multiplexer (WDM) devices, with light filtering properties, are considered. The primary objective is to control the arrival of vehicles to an intersection and schedule them to cross at times that minimize traffic delay. A further objective is to allocate delays between left-turns and forward movements, moderating the speed and slot between vehicles travelling in these directions, maintaining a safe distance from one to another. Pedestrians and bicycles are also incorporated. An I2V2V2I traffic scenario is proposed, and bidirectional communication between the infrastructure and the vehicles is tested, using the VLC request/response concept. A phasing traffic flow is developed as a proof of concept. The experimental results confirm the cooperative VLC architecture, showing that communication between connected cars and infrastructures can be optimized using the mentioned request/response concept. A significant increase in traffic throughput with the least dependency on infrastructure is achieved.

Optical satellite communication is growing fast and among various applications it requires higher throughput optical feeder links. Optical feeder links for satellite communication necessitate very high data throughput, up to 1 Terabit/s and beyond. Amongst several multiplexing strategies, dense wavelength division holds a key position to enable overall throughput rates above 1 Terabit/s. As a consequence, hardware architectures capable of handling high throughput links must be devised. Complementary to the high throughput requirement, the devices should also cope with the high optical power levels needed in optical ground stations. Combination of spatial aperture multiplexing and free space bulk optics configurations of multiplexers with transmission defraction gratings are presented as possible concepts. Besides wavelength multiplexing, it is essential to include the beam propagation effects in the performance analysis, since this may effect the overall feeder link properties. A modelling framework is presented that covers the multiplexing behavior as well as the beam propagation of the transmission gratings based concept. The modelling framework based on first principles of optical diffraction is general, and independent of the grating choice. The results suggest that the design of a free space bulk multiplexer for optical feeder link must be approached already at system level. Decisions about telescope sizing, channels distribution and modulation formats may affect the performance of the multiplexer, resulting in severe effects on the link performance. The work discusses the effect on each design parameter and proposes design guidelines for high power satellite communication beam multiplexing.

We propose the feasible design of a device that can offer a unique method for controlling the terahertz spectrum allocation, exploiting existing photonics-based technologies. We successfully designed a multiplexer and demultiplexer using arrayed waveguide grating, where the device can multiplex and demultiplex four frequency channels (8.64 GHz bandwidth) in the same operating range defined by the IEEE 802.15.3d standard with at least 10 dB separation. This study reveals that proposed solution play a major role in maturing the next generation wireless communication (beyond 100 GHz) networks.

Arrayed waveguide grating (AWG) has been widely used as a multiplexer in FBG demodulation system because of its high stability, low loss and fast read-write ability. They substitute expensive and vibration fragile spectrometers. In this paper, we compare two kinds of AWG demodulation systems experimentally. One is a multi-channel ultrasonic sensor system using fiber ring laser based on erbium-doped fiber amplifier (EDFA) and arrayed waveguide grating (AWG) as the intensity demodulator. And another is a one-way amplified system based on EDFA. When the external dynamic strains are applied on the FBG sensor, the central wavelength of the FBG will move between two adjacent channels of the AWG. Therefore, the modulation of the central wavelength of the FBG is converted to the amplitude modulation of the output of the two adjacent channels. Experimental results show that the multi-channel ultrasonic sensor system of one-way amplified configuration based on EDFA is more stable and can test high-frequency dynamic strain stably. The ultrasonic signal in water is successfully detected through one-way amplifier configuration.

In this paper, a grating assisted MDM-PDM hybrid (de)multiplexer based on the silicon-on-insulator (SOI) platform has been proposed and analyzed using coupled mode theory with effective index method (EIM). The proposed device consists of a multimode wide waveguide and five single mode narrow waveguides. The quasi- TE/TM modes of the wide waveguide are phase matched with the respective contra-propagating fundamental quasi-TE/TM modes of the single mode narrow waveguides. The phase matching conditions are satisfied by using different period gratings, which are surface corrugated on the wide waveguide. The proposed device structure exhibits good crosstalk, insertion loss, and return loss values.

A new iterative process for sorting array of signals, which differs from the known structures by uniformity and versatility, and allows direct and inverse sorting of analog or digital signal arrays was proposed in this paper. Simple relational nodes are basic elements of the proposed sorting structures. Such elements can be implemented on a different element basis, for example, on devices of selecting a maximum or minimum of two analog or digital signals, which can be implemented on CMOS current mirrors and carry out the continuous logic limited difference function. The homogeneous sorting structure on such elements implementation, consisting of two layers and a multichannel sampling and holding device was offered. Nine signals corresponding to a selection window of a matrix sensor are fed to this structure, and are sorted by five iterative steps, and at the output we receive the signals sorted by the rank, which, using the code controlled programmable multiplexer, generates an output signal, that corresponds to the selected rank. Technical parameters of such relational preprocessor were evaluated. The paper considers results of design and modeling of CL BC based on current mirrors (CM) for creating picture type image processors (IP) with matrix parallel inputsoutputs. Such sorting nodes have a number of advantages: high speed and reliability, simplicity, small power consumption, high integration level. The inclusion of an iterative node for sorting signals into a modified nonlinear IP structure makes possible to significantly simplify its design and increase the functional capabilities of such processor. The simulation results confirm the proposed approaches to the design of sorting nodes of analog signals of the iterative type. The power consumption of the processors does not exceed 2mW, the response and processing times are 10μs and can be less by an order of magnitude, the supply voltage is 1.8÷3.3V, and the operating currents are optimally in the range of 10÷20μA. The energy efficiency of the proposed preprocessor with the iterative sorting node is 25x109 operations per second per watt, which corresponds to the best technical solutions. In the work we show, that after sorting or comparative analysis of signals by levels, a promising opportunity appears to implement image processors with enhanced functionality using the new method of weighting-selecting rank differences of signals. The essence of the method is that by composing the differences of the signals ordered by rank and the upper level of their range, we can simultaneously form several resulting output signals, choosing the necessary difference signals from their set according to the control commands and weighing them additionally before the summation. We show that using this approach and the method of processing we can significantly expands the set of operations and functions for image filtering, simplifying hardware implementation of IP, especially for analog and mixed technologies. We determined set of basic executable instruction-functions of the processors, presenting the simulation results in Mathcad, PSpice OrCad and other environments. We discussed the comparative evaluation of various modifications and options for implementing processor. We analyzed the new approach for the programmable selecting function or set of functions, including the selecting the required differences between the ranks of signals and their weights. We show the results of design and modeling the proposed new FPGA-implementations of MIP. Simulation results show that processing time in such circuits does not exceed 25 nanoseconds. Circuits are simple, have low supply voltage (2.5 V), low power consumption (50mW), digital accuracy. Calculations show that in the case of using an Altera FPGA chip EP3C16F484 Cyclone III family, it is possible to implement MIP with register memory for image size of 64*64 and window 3*3 in the one chip. For the chip for 2.5V and clock frequency 200MHz the power consumption will be at the level of 200mW, and the calculation time for pixel of filters will be at the level of 25ns.

The subject of the study is an application of evolutionary algorithms to optical node optimization in dense wavelength division multiplexing optical networks. The wider context of the presented research is in essence an improvement of service flexibility and achieving savings in capital expenditures in DWDM networks. Thus, the main objective of the optimization is to minimize capital expenditure, which includes the costs of optical node resources, such as transponders and filters used in new generation of reconfigurable optical add drop multiplexers, etc. For this purpose a model based on integer programming is proposed. The efficiency of the integer programming based software is compared with that of evolutionary algorithms. The results obtained show that there is a large advantage in using evolutionary algorithms for optimizing large optical networks when compared with integer programming and mixed integer programming, whereby the two latter algorithms fail to find the optimal solution within reasonable computational time. The numerical experiments were carried out for realistic networks of different dimensions and traffic demand sets.

In this paper, we proposed a new iterative process of sorting an array of signals, which differs from the known structures of sorting signals by uniformity, versatility, which allows direct and inverse sorting of an array of analog or digital signals. The basic elements of the proposed sorting structures are simple relational nodes. Such elements can be implemented on a different element basis, including, on devices for selecting a maximum or minimum of two analog or digital signals, which are implemented on CMOS current mirrors and carry out the limited difference function of continuous logic. We offered implementation of homogeneous sorting structure on such elements, consisting of two layers and a multichannel sampling and holding device. Nine signals corresponding to a selection window of a matrix sensor are fed to this structure, we sort them in five iterative steps, and at the output we receive the signals sorted by the rank, which, using the code controlled programmable multiplexer, generates an output signal, corresponding to the selected rank. We evaluated the technical parameters of such a relational preprocessor. The base cells consist of no more than 20 CMOS 1.5μm transistors, the total power consumption of the sorting node on 10 continuously logical base cells (CL BC) is 2mW, the supply voltage is 1.8÷3.3V, the range of an input photocurrent is 0.1÷24μA, the conversion cycle is 10μs. The paper considers results of design and modeling of CL BC based on current mirrors (CM) for creating picture type image processors (IP) with matrix parallel inputs-outputs. Such sorting nodes based on them have a number of advantages: high speed and reliability, simplicity, small power consumption, high integration level. The inclusion of an iterative node for sorting signals into a modified nonlinear IP structure makes it possible to significantly simplify its design and increase the functional capabilities of such processor. The simulation results confirm the proposed approaches to the design of sorting nodes of analog signals of the iterative type, which simplify the complexity of the nodes by an order of magnitude, ensuring their uniformity, regularity and simplicity of scaling. The power consumption of the processors does not exceed 2mW, the response and processing times are 10μs and can be less by an order of magnitude, the supply voltage is 1.8÷3.3V, and the operating currents are optimally in the range of 10÷20μA. The energy efficiency of the proposed preprocessor with the iterative sorting node is 25x109 op / s•W, which corresponds to the best technical solutions. In the work we are shown, that after sorting or comparative analysis of signals by levels of selected window of image, a promising opportunity appears to implement image processors with enhanced functionality using the new method of weighting-selecting rank differences of signals. The essence of the method is that by composing the differences of the signals ordered by rank and the upper level of their range, we can simultaneously form several resulting output signals, choosing the necessary difference signals from their set according to the control commands and weighing them additionally before the summation. We are shown that using this approach and the method of processing the current window signals significantly expands the set of operations and functions for filtering images, simplifying hardware implementation of IP, especially for analog and mixed technologies. We determined set of basic possible executable instruction-functions by processors based on such a proposed method, presenting the simulation results in Mathcad, PSpice OrCad and other environments. We discussed the comparative evaluation of various modifications and options for implementing processor. We analyzed the new approach for the programmable choice of its function or set of functions, including the choice of the required differences between the ranks of signals and their weights. We show the results of design and modeling the proposed new FPGA-implementations of MIP. Simulation results show that processing time in such circuits does not exceed 25 nanoseconds. Circuits are simple, have low supply voltage (2.5 V), low power consumption (50mW), digital accuracy. Calculations show that when using an Altera FPGA chip EP3C16F484 Cyclone III family, it is possible to implement MIP with register memory for image size of 64*64 and window 3*3 in the one chip. For the chip for 2.5V and clock frequency 200MHz the power consumption will be at the level of 200mW, and the calculation time for pixel of filters will be at the level of 25ns.

This paper aims to present the optical system of th e Multispectral Camera MUX that is part of the payl oad for the CBERS 3 & 4 satellite (China Brazil Earth Resources Satellite). The CBERS program was created by Brazil and China for the development of Earth remote sensi ng satellites. The MUX camera is being developed by the Brazilian company OPTO ELETRONICA S.A. and consists of a multispectral camera with four spectral bands covering the wavelength range from blue to near inf rared (from 450nm to 890nm) with a ground resolution of 20m and a ground swath width of 120 km. Besides MUX camera (optical system, signal processing electron ics and mechanical frame), this company is also develop ing the Ground Support Equipment ‐ GSE of this camera and is responsible for structural and environmental tests. At the moment, the project is in the Qualif ication Model (QM). During this phase of the development, the camera shall be submitted to several tests, incl uding environmental, optical and structural tests with th e objective of qualify the project and start the fl ight models manufacturing.

In this paper, a dual-wavelength chaotic light source is proposed and demonstrated based on a fiber ring laser (FRL) with a semiconductor optical amplifier (SOA) as the intra-cavity gain element. By properly adjusting the bias current and the polarization, the SOA-FRL generates a high-dimension chaotic optical output with 24-nm optical bandwidth. The temporal instability of the output originates from the optical feedback, as well as the nonlinear effects of both the SOA and the long fiber. With optical-to-electrical conversion, the output electrical signal presents a bandwidth of 13 GHz, which is only limited by the bandwidth of the detection system. By inserting a tunable bandpass filter (TBPF) into the cavity, the chaotic emission bandwidth is limited to 3.2 nm. The output is then divided into two parallel channels using a wavelength division multiplexer (WDM). Autocorrelation of the two outputs confirms fair randomness, while the cross-correlation result verifies the independence of the two. With multi-bit sampling and over-sampling, dual-channel true random number generation (TRNG) up to 960 Gbps per channel is achieved. Random sampling periods are adopted to reduce the influence of the time-delay signature (TDS), which originates from the round-trip delay of the laser cavity and affects the randomness of the output. At a significance level of 0.01 and a random sampling ratio of 10-4 , the generated random bits can pass all the tests provided by the NITS SP800-22 test tool.

Optical waveguide devices based on adiabatic mode evolution have large bandwidth and fabrication tolerances, but they have longer device lengths in general. We define a suitable adiabaticity parameter for optical waveguides and derive the formulae for engineering the adiabaticity along the waveguide. The fast quasiadiabatic dynamics (FAQUAD) protocol can then be applied to redistribute adiabaticity over the length of the device, speeding up mode evolution in adiabatic waveguide devices. By homogeneously distributing the adiabaticity along the length of the devices, shortcuts to adiabaticity are found for adiabatic waveguide devices, resulting in significant length reductions from the conventional designs. Devices on silicon, including mode (de)multiplexers, polarization splitter-rotators and 3 dB couplers using the FAQUAD approach are discussed. The FAQUAD approach leads to devices that are compact, broadband, and have good fabrication tolerances.

Silicon photonics has been the subject of intense research efforts. In order to implement complex integrated silicon photonic devices and systems, a wide range of robust building blocks is needed. Waveguide couplers are fundamental devices in integrated optics, enabling different functionalities such as power dividers, spot-size converters, coherent hybrids and fiber-chip coupling interfaces, to name a few. In this work we propose a new type of nanophotonic coupler based on sidewall grating (SIGRA) concept. SIGRAs have been used in the Bragg regime, for filtering applications, as well as in the sub-wavelength regime in multimode interference (MMI) couplers. However, the use of SIGRAs in the radiation regime has been very limited. Specifically, a coarse wavelength division multiplexer was proposed and experimentally validated. In this work we study the use of SIGRAs in the diffractive regime as a mean to couple the light between a silicon wire waveguide mode and a continuum of slab waveguide modes. We also propose an original technique for designing SIGRA based couplers, enabling the synthesis of arbitrary radiation field profile by Floquet- Bloch analysis of individual diffracting elements while substantially alleviating computational load. Results are further validated by 3D FDTD simulations which confirm that the radiated field profile closely matches the target design field., Integrated Optics: Design, Devices, Systems and Applications, April 1-4, 2019, Prague, Czech Republic, Series: Proceedings of SPIE; no. 11031

In this paper, we propose a new iterative process of sorting an array of signals, which differs from the known structures of sorting signals by uniformity, versatility, which allows direct and inverse sorting of an array of analog or digital signals. The basic elements of the proposed sorting structures are simple relational nodes for analogue signals from sensor devices and cameras. Such elements can be implemented on a different element basis, including, on devices for selecting a maximum or minimum of two analog or digital signals, which are implemented, in one of the variants, on CMOS current mirrors and carry out the function of continuous logic limited difference. We offer optoelectronic implementation of such basic relational element and a homogeneous sorting structure on such elements, consisting of two layers and a multichannel sampling and holding device. Nine signals corresponding to a selection window of a matrix sensor are fed to this structure, we sort them in five iterative steps, and at the output we receive the signals sorted by the rank, which, using the code controlled programmable multiplexer, generates an output signal, corresponding to the selected rank. We evaluate the technical parameters of such a relational preprocessor for nonlinear signal processing in image processors, sorting networks, multichannel parallel type sensor, processing, and encoding systems. The base cells consist of no more than 20 CMOS 1.5μm transistors, the total power consumption of the sorting node on 10 continuously logical base cells (CL BC) is 2mW, the supply voltage is 1.8÷3.3V, the range of an input photocurrent is 0.1÷24μA, the conversion cycle is 10μs, but can be improved by selecting other transistors and some modifications of the circuits. Such mixed analog processor is modeled in PSpice OrCad. The paper considers results of design and modeling of CL BC based on photosensitive cells with an extended electronic circuit and current mirrors (CM) with functions of preliminary subsequent analogue processing for creating picture type image processors (IP) with matrix parallel inputs-outputs. Such BCs and sorting nodes based on them have a number of advantages: high speed and reliability, simplicity, small power consumption, high integration level. We consider CL BC for methods of selection and rank preprocessing. In contrast to our previous works here we will dwell more on analogue preprocessing schemes for signals of neighboring cells. Let us show how the introduction of iterative sorting nodes extends the range of functions performed by the IPs. Examples of image processing with proposed preprocessor are simulated in MathCad and show the field of application of such coprocessors and new prospects for realization of linear and matrix photo-electronic structures with matrix operands. The essential difference is that the structure is iterative and allows to significantly reducing hardware costs in comparison with other hardware implementations of sorting networks. We discuss some aspects of possible rules and principles of learning and programmable configuration for the required function, relational work, and the implementation of hardware blocks for modifying such processors.

Biological monitoring technology based on pressure sensing is a very useful for human diagnosis method as an assistive equipment, which should be comfortable on wearing position for user as well as and patient. Especially, pressure monitoring for prosthetic arm and artificial leg is the critical element to maintain the safety of the amputees. In this research, the fabrication and characterization of a novel flexible pressure sensor was done to measure the actual working pressure between the surface of human body and assistive device for biomechanical techniques. The ultimate goal of the sensor design is targeted for use in robotic and prosthetic limb, where feedback and ability to detect forces associated with slip is crucial point. To fabricate the capacitive type pressure sensor, finite element method (FEM), additive manufacturing (3D-printing) and signal processing were used. FEM simulation was performed with Comsol S/W for optimal structure design to evaluate with the structural deformation and maximum capacitance value up to 500 kPa in sensor range. Sensor with a full scale volume thickness under 10 mm were produced using FDM 3D-printingtechnique. A passive two-terminal electrical component part of capacitive pressure sensor was fabricated with conductive thermoplastic material and medium side of dielectric layer to keep soft and flexible structure. The output signal from the pressure sensor and related signal processing system was connected to a voltage divider circuit to amplifying the signal, multiplexer, microcontroller unit included analog to digital converter and indicating program. As a result, capacitive pressure sensing technology embedded in 3D printed structure can be considered for maintenance of stability and comfortability to amputees.

An optical resonator like a fiber ring (FR) or a whispering gallery mode (WGM) resonator with two couplers along its loop is referred to be in the add-drop configuration, in analogy with the add-drop multiplexer in telecom networks. Both for practical applications as well as in several fundamental studies involving high-Q resonators, this configuration is of great interest and the assessment of the intrinsic properties of the resonator and of its interaction with the coupling systems is extremely important. We developed an original method able to fully characterize high-Q resonators in an add-drop configuration. The method is based on the study of the two cavity ringdown (CRD) signals, which are produced at the transmission and drop ports by wavelength sweeping a resonance in a time interval comparable with the photon cavity lifetime. All the resonator parameters can be assessed with a single set of simultaneous measurements. We implemented the model describing the two CRD profiles from which a best fit process of the measured profiles allows deducing the key parameters. We successfully validated the model with an experiment based on a FR resonator of known characteristics. Finally, we fully characterized a high-Q, home-made, MgF2 WGM disk resonator in the add-drop configuration, assessing its intrinsic and coupling parameters.