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We present a complete characterization of reflective electroabsorption modulators (EAMs) monolithically integrated with semiconductor optical amplifiers (SOAs), components that are capable of operating beyond 50 Gb/s in the C-band. The devices are based on GaInAsP multiple quantum wells on InP substrate, leveraging semi-insulating buried heterostructure waveguide definition and butt-joint integration technologies. Different device configurations, based on 80- and 150-μm long EAMs, are fabricated and characterized in both static and dynamic modes. The frequency response of the 80 μm long EAM is still flat at 26.5 GHz (setup upper limit) whereas the 150 μm long EAM exhibits a 3-dB cutoff bandwidth of 23 GHz. A zero-chirp is achieved for EAM reverse bias voltages between −1.2 and –1.5 V depending on the wavelength. Under large-signal modulation, the frequency chirp induced by the shorter EAM is almost half that of the longer EAM, with their respective peak values being +1.5/−2 and +3.2/−3.7 GHz (rising/falling edges) at 1545 nm (−1.3 V bias, 2.6 V voltage swing). We obtained high dynamic extinction ratios of ∼14.5 and ∼8 dB from the longer and the shorter EAMs, respectively, when they are operated at 25 Gb/s using non-return-to-zero coding. Finally, we achieved 12 and 16 km colorless transmissions in the C-band (between 1530 and 1545 nm) over a standard single-mode fiber without equalization using the 150- and the 80 μm EAMs, respectively, with 4.5 and 2.5 dB dispersion penalties at a bit error rate of 10–3. [ABSTRACT FROM AUTHOR]

Increasing soil organic carbon (SOC) stocks is a promising way to mitigate the increase in atmospheric CO2 concentration. Based on a simple ratio between CO2 anthropogenic emissions and SOC stocks worldwide, it has been suggested that a 0.4% (4 per 1000) yearly increase in SOC stocks could compensate for current anthropogenic CO2 emissions. Here, we used a reverse RothC modelling approach to estimate the amount of C inputs to soils required to sustain current SOC stocks and to increase them by 4‰ per year over a period of 30 years. We assessed the feasibility of this aspirational target first by comparing the required C input with net primary productivity (NPP) flowing to the soil, and second by considering the SOC saturation concept. Calculations were performed for mainland France, at a 1 km grid cell resolution. Results showed that a 30%–40% increase in C inputs to soil would be needed to obtain a 4‰ increase per year over a 30‐year period. 88.4% of cropland areas were considered unsaturated in terms of mineral‐associated SOC, but characterized by a below target C balance, that is, less NPP available than required to reach the 4‰ aspirational target. Conversely, 90.4% of unimproved grasslands were characterized by an above target C balance, that is, enough NPP to reach the 4‰ objective, but 59.1% were also saturated. The situation of improved grasslands and forests was more evenly distributed among the four categories (saturated vs. unsaturated and above vs below target C balance). Future data from soil monitoring networks should enable to validate these results. Overall, our results suggest that, for mainland France, priorities should be (1) to increase NPP returns in cropland soils that are unsaturated and have a below target carbon balance and (2) to preserve SOC stocks in other land uses. [ABSTRACT FROM AUTHOR]

We report on the use of semiconductor optical amplifiers (SOAs) to extend the optical bandwidth of next generation optical systems to 100 nm and beyond. After discussing the technological progress and the motivation for rekindling the interest in SOAs for line amplification, we describe the innovative approach developed for the realization of ultra-wideband (UWB) SOAs. Leveraging custom design of singly polarized SOAs to provide gain over 100+ nm bandwidth, we developed a polarization diversity architecture to realize UWB-SOA modules. Embedded in a compact package, the UWB amplifier modules have been successfully used to demonstrate 100+ Tb/s transmissions. We subsequently review recent experimental transmission results based on such novel 100+ nm wide semiconductor optical amplifiers, including our first demonstration of 100+Tb/s transmission over 100 km distance, our field trial using real-time traffic, and finally the transmission of 107 Tb/s throughput over three spans of standard single mode fiber (SSMF) using hybrid UWB Raman/SOA amplification technique. [ABSTRACT FROM AUTHOR]

This article presents an experimental characterization of the impact of nonlinear impairments induced by semiconductor optical amplifiers (SOA) in a wavelength division multiplexed (WDM) coherent communication system. Motivated by a ceaseless traffic growth in optical transport systems, extending the bandwidth of the fiber link is a promising way to increase the throughput in optical networks. Using specific design, SOA can provide ultra-wideband (UWB) and continuous amplification spreading from S to L bands. For both off-the-shelf C-band SOA and UWB SOA devices, we show that SOA nonlinear impairments are not critical in the WDM regime. We report on the impact of the WDM channel count on the nonlinear distortions induced by an UWB SOA. We also demonstrate that besides having a wider bandwidth, our custom UWB SOA devices have superior performance compared to off-the shelf components even for C-band only transmission, and are well suited for wideband WDM signal amplification. [ABSTRACT FROM AUTHOR]

We report on the ultra-wideband (UWB) transmission of a 103 nm signal over 3 × 100 km of standard single mode fiber (SSMF), a widely-deployed fiber in terrestrial transmission networks. In such UWB systems, nonlinear effects such as stimulated Raman scattering (SRS) must be taken into account in the system design. We characterize the SRS impact in high power regime for this UWB spectrum. We study the evolution of SRS over the bandwidth when tilting the input spectrum to counter the inter-band power transition. We transmit 254 probabilistically constellation shaped (PCS)-64QAM channels over 300 km of SSMF and demonstrate a 107-Tb/s transmission throughput over a continuous 103 nm optical bandwidth using backward Raman pumping and SOA technology. [ABSTRACT FROM AUTHOR]

We report high speed electroabsorption modulators (EAMs), designed, fabricated and characterized within an open access generic foundry process. The EAM as a new building block is optimized in the existing platform, in which other BBs are established. By optimizing the EAM design layout, we show a static extinction ratio (static ER) of 18 dB, a low dc bias voltage below 1 V at an increased temperature, as well as operation in a semicooled environment, tested in the range of 20 °C –60 °C. Furthermore, we improve the intrinsic S-parameter response with a codesign circuit. The intrinsic 3-dB bandwidth of a 100-μm-long EAM is 17 GHz. When measured with the EAM submount design, it is increased to 24 GHz. Simultaneously, the return loss bandwidth is improved by a factor of 2.5 staying below −10 dB up to 20 GHz. Through the realization of the EAM submount design we achieve a three-time speed increase of the existing platform, from previously offered 9 GHz (using an EAM) to 24 GHz shown in this paper. [ABSTRACT FROM AUTHOR]

We report on an ultrahigh-speed PAM-based IM/DD optical subsystem featuring compact signal generation and tractable digital-processing complexity. The proposed transceiver is based on two main technologies: an InP DHBT selector power DAC for electrical signal generation, and a complexity-optimized receiver processing chain. We show how the complexity of the feed-forward equalizer can be considerably reduced by stacking a <3-symbol memory sequence estimator. Finally, we experimentally demonstrate successful signal recovery for 107-GBd PAM-4 in back-to-back configuration, and after 500 m and 1 km of transmission over standard single-mode fiber for 100- and 84-GBd PAM-4 configuration, respectively. A power-budget margin above 2 dB is attained in all cases. [ABSTRACT FROM PUBLISHER]

We report a cost-effective 40-Gb/s time-division multiplexing passive optical network downstream link using three-level electrical duobinary modulation. The transmitter consists ofa compact electroabsorption-modulated laser module. The receiver contains an avalanche photodiode packaged with a transimpedance amplifier, with digitally adjustable gain and bandwidth, followed by a duobinary decoder. Real-time eye diagram and bit-error rate (BER) measurements were performed. At a preforward error correction BER of 10-3, a power budget of 23.6 dB in back-to-back conditions is demonstrated. For a dispersion range of -215 to 128 ps/nm, the power penalty does not exceed 3 dB. [ABSTRACT FROM PUBLISHER]

The future technology migration in access networks compels the development of key innovative transmitters operating at 10 Gb/s around 1550 nm and capable of transmitting data in extended reach passive optical networks (>60 km). A laser modulated directly appears to be a low cost and a simple solution to address these needs. However, the extinction ratio and the distance of transmission are limited by frequency chirping inherent to high bit rate modulation at 1550 nm. In this letter, we demonstrate the monolithic integration of a directly modulated lasers and a ring resonator (RR) and show the possibility to engineer the RR with specific frequency modulation efficiency. The ring is used as an optical eye reshaper, which enables the increase of the extinction ratio above 9 dB. Transmissions up to 65 km with 5.8 dBm of modulated optical power coupled into the fiber are demonstrated, proving the feasibility of our transmitter for the next generation passive optical network stage 2. [ABSTRACT FROM PUBLISHER]

This paper reports a differential photoreceiver module designed for short reach applications such as access network and data center interconnect. It consists of a monolithically integrated semi-conductor optical amplifier with a PIN photodiode and a linear transimpedance amplifier (TIA) mounted on the same carrier. A matching circuit is placed between the PIN and the TIA in order to increase the cut-off frequency. The module shows a -3 dB bandwidth of 43 GHz, a single-ended conversion gain of 10 000 V/W for an optical input power of -25 dBm and a sensitivity at 40 Gb/s non-return-to-zero operation of - 22.5 dBm for a bit error rate of 10-9. [ABSTRACT FROM AUTHOR]

We demonstrate a 56-GBd pulse-amplitude modulation-4 compact InP transmitter module integrating a distributed feedback laser and an electro-absorption modulator, which exhibits 50-GHz bandwidth, >13-dB extinction ratio and up to 1.5-mW output power. Successful amplifier-free 112-Gb/s transmission is performed over 2 km using low complexity three-taps equalization. We also study the tradeoff between receiver bandwidth, equalizer length and performance, and show successful signal recovery with bandwidths as low as 18 GHz when increasing the equalizer length. [ABSTRACT FROM PUBLISHER]

We report a 2:1 rate asymmetric high serial rate time division multiplexing passive optical network (TDM-PON) with single carrier 25 Gb/s upstream and 50 Gb/s downstream. In the upstream, we present a first 25 Gb/s three-level modulated burst-mode receiver employing a 1/4-rate linear burst-mode avalanch photodiode transimpedance amplifier and a custom decoder IC. We successfully demonstrated burst-mode sensitivity of -20.4 dBm with 18 dB dynamic burst-to-burst for 25 Gb/s upstream links. In another direction, a downstream in upper O-band is proposed and demonstrated with three-level duo-binary modulation at 50 Gb/s in real time. The upstream and downstream transmission experiments show that the proposed asymmetric 50 G/25 G high serial rate TDM-PON can support $\ge$32 users while covering more than 20 km reach. [ABSTRACT FROM PUBLISHER]

This letter reports a 40-Gb/s photoreceiver module with differential outputs designed for short reach applications such as access network and data center interconnect. It consists of an indium phosphide (InP) semiconductor optical amplifier monolithically integrated with a p-i-n (SOA-PIN) photodiode, co-packaged with an InP linear transimpedance amplifier (TIA), both designed and fabricated at III-V Lab. A matching circuit is placed between the SOA-PIN and the TIA in order to increase the cutoff frequency. The module exhibits a −3 dB bandwidth of 43 GHz, a single-ended optoelectrical conversion gain of 10000 V/W for an optical input power of −25 dBm, and a record sensitivity of −22.5 dBm at a bit error rate of 10^\mathrm \mathbf -9 at 40 Gb/s in non-return-to-zero on/off-keying operation. [ABSTRACT FROM PUBLISHER]

Emergence of new applications like cloud computing, video on demand or deployment of high-speed cellular network lead to an increasing demand of high-speed short reach transmission for access network or datacenter. Due to the low sensitivity of PIN receiver and the lack of APD above 10 Gb/s, optical preamplification is a promising concept for high-speed receiver. We demonstrate an SOA-PIN/TIA receiver module which integrates an SOA-PIN photonic circuit and a TIA. This receiver has a large responsivity of 44 A/W, a polarization dependence below 2 dB, a low noise figure of 8.5 dB and a large 3-dB bandwidth of 35 GHz. Our new developed receiver achieved in NRZ a record sensitivity of −23 and −21 dBm at 25 and 40 Gb/s, respectively. [ABSTRACT FROM PUBLISHER]

We present a preamplified high-speed photoreceiver comprising a unitraveling carrier photodiode (UTC) monolithically integrated with a semiconductor optical amplifier (SOA). The SOA-UTC photoreceiver exhibits above 95-GHz 3-dB bandwidth, 8-dB noise figure, low polarization dependence loss of 1–2 dB and 95-A/W peak responsivity corresponding to record gain-bandwidth product of 6.1 THz. [ABSTRACT FROM PUBLISHER]

A specific modeling method is investigated in order to predict the large-signal modulation behavior of integrated electroabsorption modulators (EAMs) for high-speed applications in optical networks. The equivalent dynamic model includes the main nonlinearity of the EAM and takes into account the electrical and optical characteristics of the optoelectronic device. The developed specific design process is a suitable and powerful tool for simulating over wide dc bias and frequency ranges, scattering parameters, small-signal modulation response, and large-signal eye-diagram performance. Moreover, 3-D electromagnetic simulations are associated with circuit simulations to carry out for the RF input line of the EAM. This simulation model can be easily integrated in a global optical communication system simulator to estimate the temporal behavior of the modulated output optical power and then digital performances. [ABSTRACT FROM PUBLISHER]

The great interest of optical fiber links in communicating systems especially in ultra-wide band (UWB) communications has grown up in the last decade and requires co-simulation for mixed circuits design exploiting both optical and microwave domains. In this paper, we report an original modeling method of an electro-absorption modulator associated with a distributed-feedback laser to simulate an optical transmitter of an UWB over fiber system. Large signal optoelectronic device models can be developed and implemented in a high-frequency simulator, such as advanced design system-Ptolemy to analyze the performances of fiber radio links and study the impact of the transmitter characteristics. This specific simulation way, taking into account precisely electrical characteristics of both electrical and optical circuits, links two different frequency domains by coupling electrical and optical modules in the same system simulator. Therefore, a complete simulation of an UWB multi-band orthogonal frequency division multiplexing signal transmission over fiber with an external modulator is investigated. [ABSTRACT FROM PUBLISHER]

In [1], we have studied a generalization of the problem of finding a martingale on a manifold whose terminal value is known. This article completes the results obtained in the first article by providing uniqueness and existence theorems in a general framework (in particular if positive curvatures are allowed), still using differential geometry tools. [ABSTRACT FROM AUTHOR]

The problem of finding a martingale on a manifold with a fixed random terminal value can be solved by considering BSDEs with a generator with quadratic growth. We study here a generalization of these equations and we give uniqueness and existence results in two different frameworks, using differential geometry tools. Applications to PDEs are given, including a certain class of Dirichlet problems on manifolds. [ABSTRACT FROM AUTHOR]

Presents information on a study which described an active load-pull system used for measurement and control of current/voltage waveforms of microwave transistors. Description of the time domain waveforms measurement system; Measurement results; Conclusions.