The light absorption coefficient of hydrogenated nanocrystalline silicon has been engineered to h... more The light absorption coefficient of hydrogenated nanocrystalline silicon has been engineered to have a Gaussian distribution by means of absorption modification using a femtosecond laser. The absorption-modified sample exhibits a significant absorption enhancement of up to ∼700%, and the strong absorption does not depend on the incident light. We propose a model responsible for this interesting behavior. In addition, we present an optical limiter constructed through this absorption engineering method.
Nonlinear absorption (NLA) of hydrogenated nanocrystalline silicon (nc-Si:H) has been investigate... more Nonlinear absorption (NLA) of hydrogenated nanocrystalline silicon (nc-Si:H) has been investigated through the open aperture Z-scan method for the photon energy of the incident irradiance slightly less than the bandgap of the sample. NLA responses have been observed to be highly sensitive to the wavelength and intensity of the incident irradiance as well as to the bandgap of the sample, indicating greatly tunable NLA of nc-Si:H. The band tail of nc-Si:H appears to play a crucial role in such NLA responses.
In integrated photonics, the design goal of a polarization splitter/rotator (PSR) has been separa... more In integrated photonics, the design goal of a polarization splitter/rotator (PSR) has been separating the TE0 and TM0 modes in a waveguide. This is a natural choice. But in theory, a PSR only needs to project the incoming State Of Polarization (SOP) orthogonally to its output ports, using any orthogonal mode basis set in the fiber. In this article, we introduce a novel PSR design that alternatively takes the linear combination of TE0 and TM0 (TE0 +/- TM0) as orthogonal bases. By contrast, existing approaches exclusively use TE0 and TM0 as their basis set. The design is based on two symmetric and robust structures: a bi-layer taper and a Y-junction, and involves no bends. To prove the concept, we incorporated it into a four-channel polarization insensitive wavelength division multiplexing (PI-WDM) receiver fabricated in a standard CMOS Si photonics process. 40 Gb/s data rate and 0.7 +/- 0.2 dB polarization dependent loss (PDL) is demonstrated on each channel. Lastly, we propose an improved PSR design with 12 μm device length, < 0.1 dB PDL, < 0.4 dB insertion loss and < 0.05 dB wavelength dependence across C-band for both polarizations. Overall, our PSR design concept is simple, easy to realize and presents a new perspective for future PSR designs.
We demonstrate a fully independent differentialdrive capable of traveling-wave modulator in silic... more We demonstrate a fully independent differentialdrive capable of traveling-wave modulator in silicon using slowwave transmission line electrode. The reported 3.5-mm device achieves a bandwidth of 27 GHz at −1 V bias with 7.8-V small signal V π and 50-Ω impedance. Raising the impedance to this extent requires effectively expanding the RF mode size and radically changes the RF phase velocity, but we show that this can be done with minimal crosstalk effects between the two arms and overall velocity mismatch, and thus, with a high EO bandwidth achieved. 40-Gb/s operation is demonstrated with 1.6-V p p differential-drive, and performance comparisons to Lithium Niobate modulators are made.
ABSTRACT Silicon photonics has attracted extensive attention in recent years as a promising solut... more ABSTRACT Silicon photonics has attracted extensive attention in recent years as a promising solution for next generation high-speed, low energy consumption, and low cost data transmission systems. Although a few experiments indicated board-level and long haul communication capability, major and near-future application of silicon photonics is commonly seen as Ethernet at 100Gb/s and beyond, such as interconnects in data centers, where O-Band (near 1310 nm wavelength) has been standardized for its low fiber dispersion. However, almost all silicon photonics devices demonstrated up to date operate at C-Band (1530 nm to 1560 nm), the fiber loss and erbium amplification window, probably due to the wider availability of lasers and testing apparatus at this wavelength. Typical C-Band devices cannot operate at O-Band, thus the whole device library needs to be redesigned and recalibrated for O-Band applications. In this paper, we present an ultra compact, low loss, and low crosstalk waveguide crossing operating at O-Band. It is designed using the finite difference time domain method coupled with a particle swarm optimization. Device footprint is only 6 μm × 6 μm. The measured insertion loss is 0.19+/-0.02 dB across an 8-inch wafer. Cross talk is lower than -35 dB. We also report a second waveguide crossing with a 9 μm × 9 μm footprint with 0.017+/-0.005 dB insertion loss. Finally we summarize the performance of our overall O-Band device library, including low-loss waveguides, high-speed modulators, and photodetectors.
We present an ultracompact (15.3 μm long) and high-efficiency silicon-on-insulator polarization r... more We present an ultracompact (15.3 μm long) and high-efficiency silicon-on-insulator polarization rotator designed for polarization-diversified circuits. The rotator is comprised of a bilevel-tapered TM0-to-TE1 mode converter and a novel bent-tapered TE1-to-TE0 mode converter. The rotator has a simulated polarization conversion loss lower than 0.2 dB and a polarization-extinction ratio larger than 25 dB over a wavelength range of 80 nm around 1550 nm. The rotator has a SiO2 top-cladding and can be fabricated in a CMOS-compatible process.
We demonstrate a compact and low-power wavelength-division multiplexing transmitter near a 1550-n... more We demonstrate a compact and low-power wavelength-division multiplexing transmitter near a 1550-nm wavelength using silicon microrings. The transmitter is implemented on a silicon-on-insulator photonics platform with a compact footprint of 0.5 mm 2 . The transmitter incorporates 8 wavelength channels with 200-GHz spacing. Each channel achieved error-free operation at 40 Gb/s, resulting in an aggregated data transmission capability of 320 Gb/s. To our knowledge, this is the highest aggregated data rate demonstrated in silicon wavelength-division multiplexing transmitters. Owing to the small device capacitance and the efficient pn-junction modulator design, the transmitter achieves low energy-per-bit values of 36 fJ/bit under 2.4 V pp drive and 144 fJ/bit under 4.8 V pp drive. Comparisons are made to a commercial lithium niobate modulator in terms of bit-error-rate versus optical signal-to-noise ratio.
We present a silicon photonic platform offering low loss passive components, integrated highspeed... more We present a silicon photonic platform offering low loss passive components, integrated highspeed silicon traveling wave MZ modulators (30GHz), ring modulators (45GHz) and inductance peaking Germanium photodetectors (58GHz). The bandwidth of the photonic devices is sufficient to support 50Gb/s bit rate. Our platform is available to the community as part of the OpSIS project.
We present a 30 GHz silicon photonic platform that includes low-loss passive components, high-spe... more We present a 30 GHz silicon photonic platform that includes low-loss passive components, high-speed modulators and Ge-on-Si photodetectors. The platform is available to the community as part of the OpSIS-IME multi-project-wafer foundry service. We conclude with a proposal for a fully CMOS-compatible optical isolator based on multistage phase modulation.
We propose a novel silicon-on-insulator (SOI) wavelength diplexer design based on an adiabatic be... more We propose a novel silicon-on-insulator (SOI) wavelength diplexer design based on an adiabatic bent taper and an unconventional multimode waveguide. The geometry of the device is optimized using particle swarm optimization (PSO). The device has an ultra-short length of 15 μm. Simulated insertion loss at peak wavelength is less than 0.25 dB with 1-dB bandwidth around 100 nm for both O band and C band. The device is fabrication tolerant as demonstrated by simulated yield estimates. The reported design targets 1310 and 1550 nm as peak wavelengths; the design methodology is easily applicable to other wavelengths of interest.
Integrated Photonics: Materials, Devices, and Applications II, 2013
We have developed a CMOS-compatible Silicon-on-Insulator photonic platform featuring active compo... more We have developed a CMOS-compatible Silicon-on-Insulator photonic platform featuring active components such as pi-n and photoconductive (MIM) Ge-on-Si detectors, p-i-n ring and Mach-Zehnder modulators, and traveling-wave modulators based on a p-n junction driven by an RF transmission line. We have characterized the yield and uniformity of the performance through automated cross-wafer testing, demonstrating that our process is reliable and scalable. The entire platform is capable of more than 40 GB/s data rate. Fabricated at the IME/A-STAR foundry in Singapore, it is available to the worldwide community through OpSIS, a successful multi-project wafer service based at the University of Delaware. After exposing the design, fabrication and performance of the most advanced platform components, we present our newest results obtained after the first public run. These include low loss passives (Y-junctions: 0.28 dB; waveguide crossings: 0.18 dB and cross-talk -41±2 dB; non-uniform grating couplers: 3.2±0.2 dB). All these components were tested across full 8" wafers and exhibited remarkable uniformity. The active devices were improved from the previous design kit to exhibit 3dB bandwidths ranging from 30 GHz (modulators) to 58 GHz (detectors). We also present new packaging services available to OpSIS users: vertical fiber coupling and edge coupling. Downloaded From: http://proceedings.spiedigitallibrary.org/ on 07/06/2013 Terms of Use: http://spiedl.org/terms Proc. of SPIE Vol. 8767 87670G-5 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 07/06/2013 Terms of Use: http://spiedl.org/terms Proc. of SPIE Vol. 8767 87670G-7 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 07/06/2013 Terms of Use: http://spiedl.org/terms
We propose for the first time the Mod-MUX-Ring architecture for microring based WDM transmitter. ... more We propose for the first time the Mod-MUX-Ring architecture for microring based WDM transmitter. A prototype Mod-MUX-Ring transmitter with 4 channels and 400 GHz channel spacing is demonstrated and fully characterized at 40 Gb/s channel rate. Under 2.7 V driving voltage, error-free (BER < 10 −12 ) operation is achieved on all channels, with 3 dB extinction ratio. Performance comparisons to Lithium Niobate modulators are made.
10th International Conference on Group IV Photonics, 2013
Silicon photonics has emerged as a promising material system for the fabrication of photonic devi... more Silicon photonics has emerged as a promising material system for the fabrication of photonic devices as well as electronic ones. The key advantage is that many electronic and photonic functions that up to now have only been available as discrete components can be integrated into a single package. We present a silicon photonic platform that includes low-loss passive components as well as high-speed modulators and photodetectors at or above 30 GHz. The platform is available to the community as part of the OpSIS-IME MPW service.
We propose for the first time the Mod-MUX-Ring architecture for microring based WDM transmitter. ... more We propose for the first time the Mod-MUX-Ring architecture for microring based WDM transmitter. A prototype Mod-MUX-Ring transmitter with 4 channels and 400 GHz channel spacing is demonstrated and fully characterized at 40 Gb/s channel rate. Under 2.7 V driving voltage, error-free (BER < 10 −12 ) operation is achieved on all channels, with 3 dB extinction ratio. Performance comparisons to Lithium Niobate modulators are made.
We demonstrate a fully independent differentialdrive capable of traveling-wave modulator in silic... more We demonstrate a fully independent differentialdrive capable of traveling-wave modulator in silicon using slowwave transmission line electrode. The reported 3.5-mm device achieves a bandwidth of 27 GHz at −1 V bias with 7.8-V small signal V π and 50-Ω impedance. Raising the impedance to this extent requires effectively expanding the RF mode size and radically changes the RF phase velocity, but we show that this can be done with minimal crosstalk effects between the two arms and overall velocity mismatch, and thus, with a high EO bandwidth achieved. 40-Gb/s operation is demonstrated with 1.6-V p p differential-drive, and performance comparisons to Lithium Niobate modulators are made.
ABSTRACT We present silicon microring based high-speed modulator and highly tunable filter workin... more ABSTRACT We present silicon microring based high-speed modulator and highly tunable filter working near 1310 nm with CMOS compatible process. Our design shows great potential in building ultra-compact silicon photonic WDM transmitters for O-band telecommunications.
A microring-based silicon modulator operating at 40 Gb/s near 1310 nm is demonstrated for the fir... more A microring-based silicon modulator operating at 40 Gb/s near 1310 nm is demonstrated for the first time to our knowledge. NRZ-OOK signals at 40 Gb/s with 6.2 dB extinction ratio are observed by applying a 4.8 Vpp driving voltage and biasing the modulator at 7 dB insertion loss point. The energy efficiency is 115 fJ/bit. The transmission performance of 40 Gb/s NRZ-OOK through 40 km of standard single mode fiber without dispersion compensation is also investigated. We show that the link suffers negligible dispersion penalty. This makes the modulator a potential candidate for metro network applications.
We demonstrate compact, broadband, ultralow loss silicon waveguide crossings operating at 1550 nm... more We demonstrate compact, broadband, ultralow loss silicon waveguide crossings operating at 1550 nm and 1310 nm. Cross-wafer measurement of 30 dies shows transmission insertion loss of − 0.028 ± 0.009 dB for the 1550 nm device and − 0.017 ± 0.005 dB for the 1310 nm device. Both crossings show crosstalk lower than − 37 dB. The devices were fabricated in a CMOS-compatible process using 248 nm optical lithography with a single etch step.
The light absorption coefficient of hydrogenated nanocrystalline silicon has been engineered to h... more The light absorption coefficient of hydrogenated nanocrystalline silicon has been engineered to have a Gaussian distribution by means of absorption modification using a femtosecond laser. The absorption-modified sample exhibits a significant absorption enhancement of up to ∼700%, and the strong absorption does not depend on the incident light. We propose a model responsible for this interesting behavior. In addition, we present an optical limiter constructed through this absorption engineering method.
Nonlinear absorption (NLA) of hydrogenated nanocrystalline silicon (nc-Si:H) has been investigate... more Nonlinear absorption (NLA) of hydrogenated nanocrystalline silicon (nc-Si:H) has been investigated through the open aperture Z-scan method for the photon energy of the incident irradiance slightly less than the bandgap of the sample. NLA responses have been observed to be highly sensitive to the wavelength and intensity of the incident irradiance as well as to the bandgap of the sample, indicating greatly tunable NLA of nc-Si:H. The band tail of nc-Si:H appears to play a crucial role in such NLA responses.
In integrated photonics, the design goal of a polarization splitter/rotator (PSR) has been separa... more In integrated photonics, the design goal of a polarization splitter/rotator (PSR) has been separating the TE0 and TM0 modes in a waveguide. This is a natural choice. But in theory, a PSR only needs to project the incoming State Of Polarization (SOP) orthogonally to its output ports, using any orthogonal mode basis set in the fiber. In this article, we introduce a novel PSR design that alternatively takes the linear combination of TE0 and TM0 (TE0 +/- TM0) as orthogonal bases. By contrast, existing approaches exclusively use TE0 and TM0 as their basis set. The design is based on two symmetric and robust structures: a bi-layer taper and a Y-junction, and involves no bends. To prove the concept, we incorporated it into a four-channel polarization insensitive wavelength division multiplexing (PI-WDM) receiver fabricated in a standard CMOS Si photonics process. 40 Gb/s data rate and 0.7 +/- 0.2 dB polarization dependent loss (PDL) is demonstrated on each channel. Lastly, we propose an improved PSR design with 12 μm device length, &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.1 dB PDL, &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.4 dB insertion loss and &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05 dB wavelength dependence across C-band for both polarizations. Overall, our PSR design concept is simple, easy to realize and presents a new perspective for future PSR designs.
We demonstrate a fully independent differentialdrive capable of traveling-wave modulator in silic... more We demonstrate a fully independent differentialdrive capable of traveling-wave modulator in silicon using slowwave transmission line electrode. The reported 3.5-mm device achieves a bandwidth of 27 GHz at −1 V bias with 7.8-V small signal V π and 50-Ω impedance. Raising the impedance to this extent requires effectively expanding the RF mode size and radically changes the RF phase velocity, but we show that this can be done with minimal crosstalk effects between the two arms and overall velocity mismatch, and thus, with a high EO bandwidth achieved. 40-Gb/s operation is demonstrated with 1.6-V p p differential-drive, and performance comparisons to Lithium Niobate modulators are made.
ABSTRACT Silicon photonics has attracted extensive attention in recent years as a promising solut... more ABSTRACT Silicon photonics has attracted extensive attention in recent years as a promising solution for next generation high-speed, low energy consumption, and low cost data transmission systems. Although a few experiments indicated board-level and long haul communication capability, major and near-future application of silicon photonics is commonly seen as Ethernet at 100Gb/s and beyond, such as interconnects in data centers, where O-Band (near 1310 nm wavelength) has been standardized for its low fiber dispersion. However, almost all silicon photonics devices demonstrated up to date operate at C-Band (1530 nm to 1560 nm), the fiber loss and erbium amplification window, probably due to the wider availability of lasers and testing apparatus at this wavelength. Typical C-Band devices cannot operate at O-Band, thus the whole device library needs to be redesigned and recalibrated for O-Band applications. In this paper, we present an ultra compact, low loss, and low crosstalk waveguide crossing operating at O-Band. It is designed using the finite difference time domain method coupled with a particle swarm optimization. Device footprint is only 6 μm × 6 μm. The measured insertion loss is 0.19+/-0.02 dB across an 8-inch wafer. Cross talk is lower than -35 dB. We also report a second waveguide crossing with a 9 μm × 9 μm footprint with 0.017+/-0.005 dB insertion loss. Finally we summarize the performance of our overall O-Band device library, including low-loss waveguides, high-speed modulators, and photodetectors.
We present an ultracompact (15.3 μm long) and high-efficiency silicon-on-insulator polarization r... more We present an ultracompact (15.3 μm long) and high-efficiency silicon-on-insulator polarization rotator designed for polarization-diversified circuits. The rotator is comprised of a bilevel-tapered TM0-to-TE1 mode converter and a novel bent-tapered TE1-to-TE0 mode converter. The rotator has a simulated polarization conversion loss lower than 0.2 dB and a polarization-extinction ratio larger than 25 dB over a wavelength range of 80 nm around 1550 nm. The rotator has a SiO2 top-cladding and can be fabricated in a CMOS-compatible process.
We demonstrate a compact and low-power wavelength-division multiplexing transmitter near a 1550-n... more We demonstrate a compact and low-power wavelength-division multiplexing transmitter near a 1550-nm wavelength using silicon microrings. The transmitter is implemented on a silicon-on-insulator photonics platform with a compact footprint of 0.5 mm 2 . The transmitter incorporates 8 wavelength channels with 200-GHz spacing. Each channel achieved error-free operation at 40 Gb/s, resulting in an aggregated data transmission capability of 320 Gb/s. To our knowledge, this is the highest aggregated data rate demonstrated in silicon wavelength-division multiplexing transmitters. Owing to the small device capacitance and the efficient pn-junction modulator design, the transmitter achieves low energy-per-bit values of 36 fJ/bit under 2.4 V pp drive and 144 fJ/bit under 4.8 V pp drive. Comparisons are made to a commercial lithium niobate modulator in terms of bit-error-rate versus optical signal-to-noise ratio.
We present a silicon photonic platform offering low loss passive components, integrated highspeed... more We present a silicon photonic platform offering low loss passive components, integrated highspeed silicon traveling wave MZ modulators (30GHz), ring modulators (45GHz) and inductance peaking Germanium photodetectors (58GHz). The bandwidth of the photonic devices is sufficient to support 50Gb/s bit rate. Our platform is available to the community as part of the OpSIS project.
We present a 30 GHz silicon photonic platform that includes low-loss passive components, high-spe... more We present a 30 GHz silicon photonic platform that includes low-loss passive components, high-speed modulators and Ge-on-Si photodetectors. The platform is available to the community as part of the OpSIS-IME multi-project-wafer foundry service. We conclude with a proposal for a fully CMOS-compatible optical isolator based on multistage phase modulation.
We propose a novel silicon-on-insulator (SOI) wavelength diplexer design based on an adiabatic be... more We propose a novel silicon-on-insulator (SOI) wavelength diplexer design based on an adiabatic bent taper and an unconventional multimode waveguide. The geometry of the device is optimized using particle swarm optimization (PSO). The device has an ultra-short length of 15 μm. Simulated insertion loss at peak wavelength is less than 0.25 dB with 1-dB bandwidth around 100 nm for both O band and C band. The device is fabrication tolerant as demonstrated by simulated yield estimates. The reported design targets 1310 and 1550 nm as peak wavelengths; the design methodology is easily applicable to other wavelengths of interest.
Integrated Photonics: Materials, Devices, and Applications II, 2013
We have developed a CMOS-compatible Silicon-on-Insulator photonic platform featuring active compo... more We have developed a CMOS-compatible Silicon-on-Insulator photonic platform featuring active components such as pi-n and photoconductive (MIM) Ge-on-Si detectors, p-i-n ring and Mach-Zehnder modulators, and traveling-wave modulators based on a p-n junction driven by an RF transmission line. We have characterized the yield and uniformity of the performance through automated cross-wafer testing, demonstrating that our process is reliable and scalable. The entire platform is capable of more than 40 GB/s data rate. Fabricated at the IME/A-STAR foundry in Singapore, it is available to the worldwide community through OpSIS, a successful multi-project wafer service based at the University of Delaware. After exposing the design, fabrication and performance of the most advanced platform components, we present our newest results obtained after the first public run. These include low loss passives (Y-junctions: 0.28 dB; waveguide crossings: 0.18 dB and cross-talk -41±2 dB; non-uniform grating couplers: 3.2±0.2 dB). All these components were tested across full 8" wafers and exhibited remarkable uniformity. The active devices were improved from the previous design kit to exhibit 3dB bandwidths ranging from 30 GHz (modulators) to 58 GHz (detectors). We also present new packaging services available to OpSIS users: vertical fiber coupling and edge coupling. Downloaded From: http://proceedings.spiedigitallibrary.org/ on 07/06/2013 Terms of Use: http://spiedl.org/terms Proc. of SPIE Vol. 8767 87670G-5 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 07/06/2013 Terms of Use: http://spiedl.org/terms Proc. of SPIE Vol. 8767 87670G-7 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 07/06/2013 Terms of Use: http://spiedl.org/terms
We propose for the first time the Mod-MUX-Ring architecture for microring based WDM transmitter. ... more We propose for the first time the Mod-MUX-Ring architecture for microring based WDM transmitter. A prototype Mod-MUX-Ring transmitter with 4 channels and 400 GHz channel spacing is demonstrated and fully characterized at 40 Gb/s channel rate. Under 2.7 V driving voltage, error-free (BER < 10 −12 ) operation is achieved on all channels, with 3 dB extinction ratio. Performance comparisons to Lithium Niobate modulators are made.
10th International Conference on Group IV Photonics, 2013
Silicon photonics has emerged as a promising material system for the fabrication of photonic devi... more Silicon photonics has emerged as a promising material system for the fabrication of photonic devices as well as electronic ones. The key advantage is that many electronic and photonic functions that up to now have only been available as discrete components can be integrated into a single package. We present a silicon photonic platform that includes low-loss passive components as well as high-speed modulators and photodetectors at or above 30 GHz. The platform is available to the community as part of the OpSIS-IME MPW service.
We propose for the first time the Mod-MUX-Ring architecture for microring based WDM transmitter. ... more We propose for the first time the Mod-MUX-Ring architecture for microring based WDM transmitter. A prototype Mod-MUX-Ring transmitter with 4 channels and 400 GHz channel spacing is demonstrated and fully characterized at 40 Gb/s channel rate. Under 2.7 V driving voltage, error-free (BER < 10 −12 ) operation is achieved on all channels, with 3 dB extinction ratio. Performance comparisons to Lithium Niobate modulators are made.
We demonstrate a fully independent differentialdrive capable of traveling-wave modulator in silic... more We demonstrate a fully independent differentialdrive capable of traveling-wave modulator in silicon using slowwave transmission line electrode. The reported 3.5-mm device achieves a bandwidth of 27 GHz at −1 V bias with 7.8-V small signal V π and 50-Ω impedance. Raising the impedance to this extent requires effectively expanding the RF mode size and radically changes the RF phase velocity, but we show that this can be done with minimal crosstalk effects between the two arms and overall velocity mismatch, and thus, with a high EO bandwidth achieved. 40-Gb/s operation is demonstrated with 1.6-V p p differential-drive, and performance comparisons to Lithium Niobate modulators are made.
ABSTRACT We present silicon microring based high-speed modulator and highly tunable filter workin... more ABSTRACT We present silicon microring based high-speed modulator and highly tunable filter working near 1310 nm with CMOS compatible process. Our design shows great potential in building ultra-compact silicon photonic WDM transmitters for O-band telecommunications.
A microring-based silicon modulator operating at 40 Gb/s near 1310 nm is demonstrated for the fir... more A microring-based silicon modulator operating at 40 Gb/s near 1310 nm is demonstrated for the first time to our knowledge. NRZ-OOK signals at 40 Gb/s with 6.2 dB extinction ratio are observed by applying a 4.8 Vpp driving voltage and biasing the modulator at 7 dB insertion loss point. The energy efficiency is 115 fJ/bit. The transmission performance of 40 Gb/s NRZ-OOK through 40 km of standard single mode fiber without dispersion compensation is also investigated. We show that the link suffers negligible dispersion penalty. This makes the modulator a potential candidate for metro network applications.
We demonstrate compact, broadband, ultralow loss silicon waveguide crossings operating at 1550 nm... more We demonstrate compact, broadband, ultralow loss silicon waveguide crossings operating at 1550 nm and 1310 nm. Cross-wafer measurement of 30 dies shows transmission insertion loss of − 0.028 ± 0.009 dB for the 1550 nm device and − 0.017 ± 0.005 dB for the 1310 nm device. Both crossings show crosstalk lower than − 37 dB. The devices were fabricated in a CMOS-compatible process using 248 nm optical lithography with a single etch step.
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Papers by Yangjin Ma