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With the ever-increasing demand for small channel spacing in the dense wavelength division multiplexing technology, and the wavelength shift arising from the fabrication dimensional sensitivity of the silicon optical communication devices, wavelength tuning methods for silicon multiplexer/demultiplexer are therefore of great interest. Thermo-optically tunable silicon arrayed waveguide grating (AWG) multiplexer/demultiplexer using TiN heater has been demonstrated for the first time. Reduced impact of fabrication nonuniformity on the AWG effective refractive index is achieved through the waveguide design. Uniform heating is achieved by the heater design, which is analyzed by thermal distribution simulation. Above 600 GHz channel tunability has been demonstrated by simulation and experiment.

We propose and experimentally demonstrate a novel scheme for simultaneous optical sensing of electric memory cell states. Results show that the effective sensing speed can be enhanced by 976 times with 100 nm spectrum ranges.

SUMMARY 20-Gbps non return-to-zero (NRZ) — binary phase shift keying (BPSK) using the silicon Mach-Zehnder modulator is demonstrated and characterized. Measurement of a constellation diagram confirms successful modulation of 20-Gbps BPSK with the silicon modulator. Transmission performance is characterized in the measurement of bit-error-rate in accumulated dispersion range from −347 ps/nm to +334 ps/nm using SMF and a dispersion compensating fiber module. Optical signal-to-noise ratio required for bit-error-rate of 10 −3 is 10.1 dB at back-to-back condition. It is 1.2-dB difference from simulated value. Obtained dispersion tolerance less than 2-dB power penalty for bit-error-rate of 10−3 is −220 ps/nm to +230 ps/nm. The symmetric dispersion tolerance indicates chirp-free modulation. Frequency chirp inherent in the modulation mechanism of the silicon MZM is also discussed with the simulation. The effect caused by the frequency chirp is limited to 3% shift in the chromatic dispersion range of 2 dB power penalty for BER 10 −3 .T he effect inherent in the silicon

We propose CMOS-compatible multi-layered waveguide system for silicon hybrid integration. Numerical simulation of vertical light coupling between different layers, and fabrication of dual-layered waveguide devices for multiple die-to-wafer bonding are performed, suggesting the integration feasibility.

A 3D silicon photonics packaging architecture based on a Cu-metallized Si-photonics through-silicon-via (TSV) interposer has been designed and experimentally demonstrated, which achieves flexible and compact electro-optical integration of different functionalities for high density on-board optics module. 3D photonics architecture for on-package integration overcomes the difficulties in sophisticated co-integration electronic design automation (EDA) tool and processing skills of monolithic integration. This photonic TSV interposer consists of monolithically integrated TSV, tunable arrayed waveguide grating (AWG), optical (Mach-Zehnder Interferometer) modulators and germanium photodetectors (PD). The fabrication process of this 3D photonics architecture is presented. 800 GHz channel tunability is achieved by the tunable AWG, and 20 GHz-bandwidth and 28 GHz-bandwidth is achieved by the silicon modulator and germanium PD on this on-package TSV integration module, respectively. This 3D photonics module realizes a 30 Gbps-data rate. This work has established the toolboxes of 3D silicon photonics packaging based on TSV interposer for high density on-board optics module.

Despite all the eminent advantages of silicon photonics, other materials need to be integrated to fulfill the functions that are difficult to realize with silicon alone. This is because silicon has a low light emission efficiency and a low electro-optic coefficient, limiting the use of silicon as a material for light sources and modulators. A strong two-photon absorption (TPA) at high intensities also limits the use of silicon in applications exploiting nonlinear effects. In addition, signal amplification is needed to compensate the insertion and propagation losses in silicon nanowaveguides. To address these issues we have demonstrated the integration of atomic layer deposited nanolaminates on silicon waveguides. Firstly we demonstrate slot waveguide ring resonators patterned on a silicon-on-insulator (SOI) wafer coated with an atomic layer deposited organic/inorganic nanolaminate structure, which consists of alternating layers of tantalum pentoxide (Ta2O5) and polyimide (PI) [1]. These materials were selected since the ALD process for depositing Ta2O5/PI nanolaminate films is already available [2] and both materials exhibit high third order nonlinearities [3-4]. In our nanolaminate ring resonators, the optical power is not only confined in the narrow central air slot but also in several parallel sub-10 nm wide vertical polyimide slots. This indicates that the mode profiles in the silicon slot waveguide can be accurately tuned by the atomic layer deposition (ALD) method. Our results show that ALD of organic and inorganic materials can be combined with conventional silicon waveguide fabrication techniques to create slot waveguide ring resonators with varying mode profiles. Secondly we demonstrate the integration of atomic layer deposited erbium-doped aluminum oxide (Al2O3) nanolaminates on silicon waveguides. This method provides an efficient way for controlling the concentration and distribution of erbium ions. We have applied this method on silicon strip and slot waveguides and show signal enhancement. Our results show that atomic layer deposited nanolaminates can potentially open new possibilities for various photonic applications, such as silicon photonic devices for light emission and amplification, optical sensing and all-optical signal processing. References [1] A. Autere, L. Karvonen, A. Saynatjoki, M. Roussey, E. Farm, M. Kemell, X. Tu, T.Y. Liow, G.Q. Lo, M. Ritala, M. Leskela, S. Honkanen, H. Lipsanen, and Z. Sun, "Slot waveguide ring resonators coated by an atomic layer deposited organic/inorganic nanolaminate," Opt. Express 23, 26940-26951 (2015) [2] L. D. Salmi, E. Puukilainen, M. Vehkamaki, M. Heikkila, and M. Ritala, “Atomic layer deposition of Ta2O5/polyimide nanolaminates,” Chem. Vap. Deposition 15, 221–226 (2009). [3] S. Morino, T. Yamashita, K. Horie, T. Wada, and H. Sasabe, “Third-order nonlinear optical properties of aromatic polyisoimides,” React. Funct. Polym. 44, 183–188 (2000). [4] C.-Y. Tai, J. Wilkinson, N. Perney, M. Netti, F. Cattaneo, C. Finlayson, and J. Baumberg, “Determination of nonlinear refractive index in a Ta2O5 rib waveguide using self-phase modulation,” Opt. Express 12, 5110–5116 (2004).

3D electro-optical integration based on a Cu-based Si-photonics TSV interposer has been demonstrated for integrated optical communication applications. The photonics TSV interposer consisting of monolithically integrated TSV, modulators and photodetectors, enabling a 30 Gbps-data-rate.

Micron-scale disk resonators are explored to minituarize and enhance Ge-on-Si photodetectors. A 2.0 μm-radius detector exhibits a dark current of 11 nA, a responsitivity of 0.5 A/W and a 3-dB bandwidth of 17 GHz at −1V bias.

We demonstrate 10-Gb/s high-on/off-contrast modulation of a carrier-depletion silicon Mach-Zehnder modulator having 3-mm rib-waveguide phase shifter driven with RF 3.6 VPP or lower at temperatures up to 130 °C without thermo-electric cooling.

CMOS-compatible silicon photonics technology is becoming a promising candidate to realize very large-scale complex photonics-CMOS integration system. For the purpose of CMOS-compatible complete-Cu integration, a traveling-wave electrode (TWE) of a silicon optical modulator via Cu-based back-end-of-line (BEOL) process is demonstrated in this work. A latticed Cu surface pattern is designed for the requirement of Cu-BEOL process. The Cu-TWE is modeled on aspects of the group velocity match and the characteristic impedance match. The dual-damascene based Cu-BEOL fabrication process for the TWE and the contact plugs of the modulator is presented. Finally, the experiment and characterization results are presented, and above 30 GHz-bandwidth can be achieved.

We present silicon-based WDM photonics link for 240 Gb/s data transmission on 1.3 μm with above 50 GHz silicon modulator and 20GHz Germanium photo-detector. Photonics link has a bandwidth of 53.4GHz limited by the impedance mismatch.

In this letter, we present a carrier-induced silicon waveguide Bragg grating filter with a p-i-n junction. The carrier-induced Bragg grating is formed on the rib silicon waveguide by ion implantation technology. The bandwidth and the extinction ratio of the filter are 0.3 nm and 14 dB, respectively. It can be tuned by both forward and reverse biases. The central wavelength shifting rates under forward and reverse biases are 1.35 and 0.52 pm/V, respectively. The extinction ratio can also be tuned. At the forward bias of 1.5 V, the extinction ratio is reduced from 14 to 5 dB.

Slot waveguide based ring resonators filled with atomic layer deposited (ALD) aluminum oxide (Al2O3) were fabricated and characterized. Our results demonstrate that ALD can be used to create slot waveguide ring resonators with relatively high Q-factors, which opens new possibilities for various photonic applications, such as optical sensing and all-optical signal processing.

We demonstrate a high-efficiency and CMOS-compatible silicon Mach-Zehnder Interferometer (MZI) optical modulator with Cu traveling-wave electrode and doping compensation. The measured electro-optic bandwidth at Vbias = -5 V is above 30 GHz when it is operated at 1550 nm. At a data rate of 50 Gbps, the dynamic extinction ratio is more than 7 dB. The phase shifter is composed of a 3 mm-long reverse-biased PN junction with modulation efficiency (Vπ·Lπ) of ~18.5 V·mm. Such a Cu-photonics technology provides an attractive potentiality for integration development of silicon photonics and CMOS circuits on SOI wafer in the future.

A silicon Cu-photonics interposer, consisting of monolithically integrated Si modulators and Ge photodetectors, has been explored for integrated optical communication. Up to 33.7 GHz-bandwidth of this integrated circuit are enabled by travelling-wave electrode via Cu-BEOL.

We demonstrated the applications of our Si 3 N 4 -on-SOI platform for O-band operation with propagation and interlayer transition loss of ∼0.24dB/cm and ∼0.2dB, respectively. We also characterized our SOI-based Ge photo-detector and silicon modulator at λ= 1310nm.

High-performance silicon optical modulator is demonstrated with up to 50-Gb/s data rate upon 1.3-V pp . The measured extinction ratios of the optical eye-diagrams are respectively 5.97-dB, 5.13-dB and 4.44-dB at 28-Gb/s, 40-Gb/s and 50-Gb/s data rate.

We demonstrate silicon-based traveling-wave photodetector arrays (Si-TWPDAs) with parallel optical feeding by integrating multiple Germanium photodetectors. Such Si-TWPDAs feature the merit of high optical saturation power with remaining the large operation bandwidth. The impedance-matched traveling-wave electrode design takes into account the individual Ge photodetector loading effect. Optical waveguide delay lines are designed in order to balance the electrical phase delay of the traveling-wave electrode. The maximum linear photocurrent at −4V biased voltage are respectively 16 mA, 38 mA, and 65 mA with integrating 1, 2, and 4 photodetectors, upon the saturation power of 40 mW, 100 mW, and 160 mW. This corresponds to a normalized photocurrent generation of >0.32 mA/µm3 and a normalized saturation power of 0.8 mW/µm3. The extracted fiber access responsivity is ~0.42 A/W and the intrinsic responsivity of ~0.82 A/W. The measured 3-dB bandwidth for 4-channel TWPDA is ~20 GHz.

A low-loss high-speed silicon in-phase (I) quadrature (Q) modulator is designed, fabricated and characterized. The fabricated IQ modulator has a low passive optical loss of 9 dB in C and L bands. Using the modulator, differential quadrature phase-shift keying (DQPSK) transmission at 44.6 Gb/s with differential detection is confirmed with an optical signal-to-noise ratio (OSNR) of 16.3 dB for a bit error rate (BER) of 10(-3) and a dispersion tolerance of -96 to 107 ps/nm. Moreover, in digital coherent detection, quadrature phase-shift keying (QPSK) up to 64 Gb/s are achieved with an OSNR of 11.6-11.8 dB for a BER of 10(-2) at 1530, 1550, and 1610 nm.

10-Gb/s silicon-based Mach-Zehnder modulator is packaged and characterized. The I/O sections of the modulator chip are located at longer-facet sides using bends waveguides for enhancing modulation bandwidth by using short straight configuration of traveling-wave electrodes. Low-insertion loss and high-return-loss optical coupling structure between input/output lenses and the modulator chip is achieved with optical coupling, where both of chip facets and inverted-taper mode-field-convertors are angled with respect to incident light beam. 3-dB electro-optic bandwidth is as high as 12.0-GHz and optical insertion loss is 9-dB or lower. High-contrast eye diagram with an extinction ratio of 13.8-dB is obtained.

The wavelength band near 1300 nm is attractive for many telecommunications applications, yet there are few results in silicon that demonstrate high-speed modulation in this band. We present the first silicon modulator to operate at 50 Gbps near 1300 nm. We demonstrate an open eye at this speed using a differential 1.5 V(pp) signal at 0 V reverse bias, achieving an energy efficiency of 450 fJ/bit.

We demonstrate the first silicon-based parallel-fed travelling-wave photodetector array (TWPDA). Impedance-matched travelling-wave electrode is designed considering periodic loading effect. The demonstrated up to 4-channel TWPDAs show >10GHz 3-dB bandwidths and ~0.75A/W responsivity using 30µm-length PDs.

A silicon traveling-wave Mach-Zehnder modulator near 1300 nm is demonstrated to operate at 50 Gb/s with a differential 2 Vpp signal at 0 V reverse bias, achieving a 800 fJ/bit power consumption.

128-Gb/s DP-QPSK is realized using silicon IQ modulator monolithically integrated with partial-rib polarization rotator under +/−3.25-Vpp push-pull RF driving condition. Low passive insertion loss 12–13 dB is achieved over C band.

We investigate the performances of a silicon PN-junction Mach-Zehnder modulator for analog application. The slope efficiency and spurious-free dynamic range (SFDR) of such a modulator upon carrier depletion and carrier injection effects are characterized and compared. Input RF frequency-dependence measurements show that the depletion-type modulator is usually with ~20 dB ∙ Hz(2/3) higher SFDR comparing to the injection-type modulator, yet with an order-of-magnitude lower slope efficiency. For the depletion-type and injection-type modulators, the measured maximum SFDRs are respectively ~95 dB ∙ Hz(2/3) and 75 dB∙Hz(2/3), with maximum slope efficiency of 0.3 V(-1) and 8 V(-1

We demonstrate silicon Mach-Zehnder Interferometer (MZI) optical modulator with 50.1-Gb/s data rate and 5.56 dB dynamic extinction ratios. The phase shifter is composed by a 4 mm-long reverse-biased p-n junction with a modulation efficiency (V(π) · L(π)) of ~26.7 V · mm and phase shifter loss of ~1.04 dB/mm at V(bias) = -6 V. The measured electro-optic bandwidth reaches 25.6 GHz at V(bias) = -5 V. Compensation doping method and low loss traveling-wave electrodes are utilized to improve the modulator performance. Measurement result demonstrates that reasonable choosing of working point and doping profile of the silicon optical modulator is critical in order to match the performance requirement of the real application.

Transmission measurements are performed using a low-loss zero-chirp silicon Mach-Zehnder modulator in 20-Gb/s DPSK with accumulated dispersion of -347 ps/nm to +334 ps/nm. Dispersion tolerance for 2-dB path penalty is as high as 550 ps/nm.

We demonstrate a cost-effective silicon microring-based bio/chemical sensor, which integrates vertical grating couplers, two cascaded microrings for optical sensing and electrical tracing, and Ge photodetector for direct sensing interrogation. Detection limit of 1.5×10-5 is demonstrated.

20-Gbps NRZ-BPSK operation using silicon MZM is demonstrated with excellent chirp-free performance. Obtained α-parameter of the modulator is −0.05, and the low chirp modulation under push-pull operation is observed.

Silicon Mach-Zehnder modulators with reduced series resistance in lateral PN junction rib-waveguide phase shifters for enhanced high-speed response are fabricated and characterized. Extinction ratio higher than 10 dB is obtained at 10.3-11.7 Gbps with mask margins of 27% (10.3-Gbps 10GBE), 16% (10.7-Gbps STM-64/OC-192) and 10% (11.3-Gbps STM-64/OC-192) in eye-diagram measurements incorporating mask tests using a RF cut-off filter. In unfiltered eye-diagram measurements without mask tests, extinction ratio higher than 13 dB is obtained at 10.0-12.5 Gbps. The silicon modulators reveal high-speed performance comparable with that of lithium-niobate modulators in high-speed optical fiber telecommunications.

We demonstrate silicon-based multiple-slot waveguides filled with dual atomic layer deposited oxide layers. Slot modes for both polarizations, transverse electric (TE) and transverse magnetic (TM), are supported in the waveguide. Propagation loss in the order of 8 dB/cm is achieved for the TE-polarization and 4 dB/cm for the TM-polarization in the waveguides with dual (Al 2 O 3 -TiO 2 ) thin film layers. The devices are fabricated using low-temperature complementary metal-oxide-semiconductor compatible processes. To our knowledge, this is the first demonstration of dual-filled slot waveguides.

Silicon photonic waveguide nested Mach-Zehnder modulators having rib-waveguide planar P-N junction phase shifters are fabricated and characterized in constellation and transmittance measurements. 20-Gbps QPSK constellation is observed with optical loss lower than 15 dB at wavelengths of 1550 and 1590 nm.

We demonstrate low-loss silicon slot waveguides filled with single and dual atomic layer deposited oxide layers. Propagation losses less than 5 dB/cm and 8 dB/cm are achieved for the waveguides with single (Al 2 O 3 ) and double (Al 2 O 3 -TiO 2 ) layers, respectively. The devices are fabricated using low-temperature CMOS compatible processes. The geometries allow nonlinearities nearly two orders of magnitude smaller than plain silicon waveguides.

Silicon photonics, being an important technology platform for a wide range of applications, demands an easily assessable fabrication foundry with the flexibility desired for research and development of integrated photonics circuits, as well as with the manufacturing path required for volume production.

We propose and demonstrate a cost effective electrical tracing-assisted silicon microring sensor system which comprises one sensing microring and another thermo-optical-tunable tracing microring. Proof-of-principle demonstation by testing polyelectrolyte multilayer shows the sensitivity of 3.75 mW/ng·mm2.

For RF-/microwave-applications, the loss of the current optical silicon modulator (typical ∼1 dB/mm) is still too high for commercial using compared with that of Lithium Niobate modulator. Approaches for reducing the loss often compromise with the degradation of the other two key performance parametric including modulation efficiency and switching speed. In this work, we achieved the reduction of the phase shifter loss by optimizing the doping level of the modulator while keeping the modulation efficiency and switching speed still at a high level. 10Gbit/s silicon modulator is realized with 0.7 dB/mm phase shift loss and phase shift efficiency V π L π = 3.4V·cm. The phase shift loss can also be reduced to 0.45 dB/mm with efficiency V π L π = 4.3V·cm. Compensated doping method is utilized to optimize the doping level along the cross section of the phase shifter.

Compared with an optical modulator based on lithium niobate, the total loss of the current high speed silicon modulator is still too high for commercial use. Reduction of the total loss always comes along with the degradation of the other two characteristics including modulation efficiency or switching speed. In this paper, we reduce the phase shifter loss through optimizing the doping level out of the depletion region while keeping the modulation efficiency and switching speed at a high level. Compensated doping method is utilized to optimize the doping level on the cross section of the phase shift. With doping compensation, the Loss·Efficiency figure-of-merit (FOM) of 4 mm phase shifter is reduced from 25.8 dB·V to 19.4 dB·V while still keeping the small signal 3 dB-bandwidth at about 10 GHz. After doping profile optimizing, the measured bandwidth of the phase shifter with doping compensation can even reaches 17 GHz with a Loss·Efficiency FOM of about 25.4 dB·V.

Depletion mode silicon modulators with an extinction ratio of >10 dB at 12.5 Gbps and a phase-shifter optical loss of 4 dB is reported. A novel technique further reduces the optical loss, bridging the performance gap between silicon and LiNbO 3 modulators.

Silicon Mach-Zehnder modulators with reduced series resistance in lateral PN junction rib-waveguide phase shifters are characterized in eye-diagram measurements. The modulators reveal extinction ratio beyond 10dB at 10.0–12.5Gbps, approaching lithium-niobate modulators in high-speed performance.

Micro-cavity structure composed of silicon wire with 240 nm square cross section and two symmetrical sidewall waveguide Bragg gratings is fabricated and studied for the operation under telecommunication wavelengths. Optical filter of quasi-TE mode was realized based on this cavity. In such micro-cavity, optical quality factor (Q) was measured up to 380 with a 4.8 nm free spectral range (FSR) and 12 dB fringe contrast (FC). The measured group index of silicon waveguide with only 240 nm square cross section was between 3.80 and 5.43. It is the first time group delay of silicon wire waveguide with such small core dimension is studied. Larger group delay can be expected after optimizing the design parameters and the fabrication process.

Inversely tapered spot size converter (SSC) is widely used to connect silicon waveguide with fiber in silicon photonics. However, the tapered structure may cause polarization rotation and further generate interference fluctuation in the transmission spectrum even of a straight waveguide. We analyzed the light propagation in a straight waveguide with SSC at the both ends with coupling matrix and transmission matrix methods. The analysis results matched with the phenomena we observed in the transmission spectrum. Combining the analysis with the measurement results, we calculated the polarization rotation efficiency of the SSC in different samples and analyzed the origin of the polarization rotation effect. Finally, we discussed the influence of the effect to the DP-QPSK signal and proposed several methods to release the impact.

In this study, slot waveguide ring resonators patterned on a silicon-on-insulator (SOI) wafer and coated with an atomic layer deposited nanolaminate consisting of alternating layers of tantalum pentoxide and polyimide were fabricated and characterized. To the best of our knowledge, this is the first demonstration of atomic layer deposition (ALD) of organic materials in waveguiding applications. In our nanolaminate ring resonators, the optical power is not only confined in the narrow central air slot but also in several parallel sub-10 nm wide vertical polyimide slots. This indicates that the mode profiles in the silicon slot waveguide can be accurately tuned by the ALD method. Our results show that ALD of organic and inorganic materials can be combined with conventional silicon waveguide fabrication techniques to create slot waveguide ring resonators with varying mode profiles. This can potentially open new possibilities for various photonic applications, such as optical sensing and all-optical signal processing.

We present a low-loss and small-footprint polarization rotator based on mode evolution. The polarization rotator is composed of an asymmetric-rib waveguide and a tapered waveguide, both of which consist only of a silicon core and a silica cladding. The rotator is fabricated under the same design rules as other device blocks, such as rib-waveguide phase shifters for photonic integration. The polarization rotator is fabricated using CMOS-based processes and provides polarization rotations with an on-chip insertion loss lower than 0.5 dB from transverse-electric (TE) to transverse-magnetic (TM) polarization and a loss lower than 1.0 dB from the TM to TE polarization in a 200 nm wavelength range extending over C and L bands.

High-index-contrast (HIC) waveguide such as Si and Si3N4 has small mode size enabling compact integration. However, the coupling loss with single mode fiber is also remarkable owning to the mode mismatching. Therefore, mode size converter, as the interface between HIC waveguide and optical fiber, takes an important role in the field of integrated optics. The material with refractive index (RI) between HIC waveguide and optical fiber can be used as a bridge to reduce the mode mismatching loss. In this letter, we employ silicon oxynitride (SiON) with RI about 1.50 as the intermediate material and optimize the structure of the SiON waveguide to match with cleaved single mode fiber and HIC waveguide separately. Combined with inverse taper and suspended structure, the mismatching loss is reduced and the dependence to the dimension of the structure is also released. The coupling loss is 1.2 and 1.4 dB/facet for TE and TM mode, respectively, with 3 dB alignment tolerance of ± 3.5 μm for Si(3)N(4) waveguide with just 200 nm-wide tip. While for Si waveguide, a critical dimension of 150 nm is applied due to the higher index contrast than Si(3)N(4) waveguide. Similar alignment tolerance is realized with coupling loss about 1.8 and 2.1 dB/facet for TE and TM mode. The polarization dependence loss (PDL) for both platforms is within 0.5 dB.

A silicon Mach-Zehnder Interferometer (MZI) optical modulator with a shield coplanar waveguide (CPW) transmission line electrode design was demonstrated. This shield-CPW electrode suppresses the signal distortion caused by the parasitic slot-line (SL) mode and improves the electrical bandwidth and the electro-optical (EO) bandwidth. With the shield-CPW electrodes and 5.5 mm-long phase shifters, the silicon MZI optical modulator delivered an EO bandwidth of above 24 GHz and a V (π) = 3.0 V was achieved at λ = 1310 nm. When modulated at 28-Gb/s data rate, it achieved an extinction ratio of 5.66 dB under a driving voltage of V (pp) = 1.3 V, corresponding to a power consumption of 0.8 pJ/bit.

We demonstrate a silicon-based optoelectronic integrated circuit (OEIC) for label-free bio/chemical sensing application. Such on-chip OEIC sensor system consists of optical grating couplers for vertical light coupling into silicon waveguides, a thermal-tunable microring as a tunable filter, an exposed microring as an optical label-free sensor, and a Ge photodetector for a direct electrical readout. Different from the conventional wavelength-scanning method, we adopt low-cost broadband ASE light source, together with the on-chip tunable filter to generate sliced light source. The effective refractive index change of the sensing microring induced by the sensing target is traced by scanning the supplied electrical power applied onto the tracing microring, and the detected electrical signal is read out by the Ge photodetector. For bulk refractive index sensing, we demonstrate using such OEIC sensing system with a sensitivity of ~15 mW/RIU and a detection limit of 3.9 μ-RIU, while for surface sensing of biotin-streptavidin, we obtain a surface mass sensitivity of Sm = ~192 µW/ng·mm−2 and a surface detection limit of 0.3 pg/mm2. The presented OEIC sensing system is suitable for point-of-care applications. Published version

In this work, we demonstrate thermo-optical quasi-digital optical switch (q-DOS) using silicon microring resonator-coupled Mach-Zehnder interferometer. The optical transmission spectra show box-like response with 1-dB and 3-dB bandwidths of ~1.3 nm and ~1.6 nm, respectively. Such broadband flat-top optical response improves the tolerance to the light source wavelength fluctuation of ± 6 A and temperature variation of ± 6 °C. Dynamic characterizations show the device with switching power of ~37 mW, switching time of ~7 μs, and on/off ratio of > 30 dB. For performance comparison, we also demonstrate a carrier injection-based electro-optical q-DOS by integrating lateral P-i-N junction with the microring resonator, which significantly reduces power consumption to ~12 mW and switching time to ~0.7 ns only.

Important active technologies, modulators, photodetectors, and thermooptics for low-energy silicon optical interconnects are discussed. High-speed performance up to 40 Gb/s is reported for the silicon modulators and germanium photodetectors, and approaches for further improvement in speed and efficiency are presented. Low-voltage avalanche multiplication is demonstrated, giving a gain-bandwidth product of 75 GHz, while the combined effects of multiplication gain and the Franz-Keldysh effect enable a 5-μm-long germanium photodetector to achieve responsivity in the L-band that is comparable to that in the C-band. With trench-based thermal isolation, a low switching power of 0.4 mW is achieved for a thermooptic switch.