Zhenping Xing

High-speed low-chirp PAM-4 transmission based on push-pull silicon photonic microring modulators

We report a silicon photonic modulator based on the use of dual parallel microring modulators (MRMs) inserted in a Mach-Zehnder interferometer (MZI). It is operated in a push-pull configuration for low-chirp transmission at approximately 1550 nm. The chirp parameters of the device are measured using 10 Gb/s on-off keying (OOK) transmission over 20 km of standard single mode fiber (SSMF), and they are less than 0.01, showing the low-chirp characteristic of the modulator. We further demonstrate four-level pulse amplitude modulation (PAM-4) transmission at 92 Gb/s over 1 km of SSMF and at 40 Gb/s over 20 km of SSMF. The measured bit error rates (BERs) are below the hard-decision (HD) forward error correction (FEC) threshold of 3.8 × 10-3.

Single wavelength 480 Gb/s direct detection over 80km SSMF enabled by Stokes vector Kramers Kronig transceiver

We propose 4D modulation with directed detection employing a novel Stokes-Vector Kramers-Kronig transceiver. It shows that employing Stokes vector receiver, transmitted digital carrier and Kramers-Kronig detection offers an effective way to de-rotate polarization multiplexed complex double side band signal without using a local oscillator at receiver. The impact of system parameters and configurations including carrier-to-signal-power ratio, guard band of the digital carrier, oversampling ratio and real MIMO is experimentally investigated. Finally, a record 480 Gb/s data rate over 80 km SSMF is achieved in a 60 Gbaud PDM-16QAM single carrier experiment with a BER below the threshold of 2.0x10-2

Silicon Photonic Ring-Assisted MZI for 50 Gb/s DAC-Less and DSP-Free PAM-4 Transmission

We present the design and characterization of a silicon photonic ring-assisted Mach–Zehnder interferometer for four-level pulse amplitude modulation (PAM-4) short-reach transmission without the use of digital-to-analog converter (DAC) or digital signal processing (DSP). The PAM-4 optical signals are generated by driving two microring modulators with independent 2-level radio frequency signals. The device is operated at 25 Gbaud and the PAM-4 optical signals are transmitted over 2 km of standard single mode fiber. The bit error rate is estimated to be lower than the hard-decision forward error correction threshold of

Broadband sub-wavelength grating coupler for O-band application

3.8 \times 10^{-3}

Compact single-etched sub-wavelength grating couplers for O-band application

, showing a successful DAC-less and DSP-free PAM-4 transmission at 50 Gb/s.

Polarization Beam Splitter Based on MMI Coupler With SWG Birefringence Engineering on SOI

We demonstrate a broadband sub-wavelength grating coupler for the O-band application, which has a simulated coupling efficiency of −3.3 dB with 3-dB bandwidth of 78 nm and a measured coupling efficiency of −4.5 dB with a 3-dB bandwidth of 65 nm for fundamental TE mode.

A CMOS Compatible Ultracompact Silicon Photonic Optical Add-Drop Multiplexer with Misaligned Sidewall Bragg Gratings

We demonstrate two single-etched sub-wavelength grating coupler (SWGC) designs for O-band application, one targeting at high coupling efficiency and the other targeting at broad operating bandwidth. The high-efficiency SWGC has a measured peak coupling efficiency of -3.8 dB and a 3-dB bandwidth of 40 nm, and the broadband SWGC has a measured peak coupling efficiency of -4.3 dB and a 3-dB bandwidth of 71 nm. Focusing gratings have been used in our SWGCs to reduce the design footprints and the dimensions of our SWGCs are smaller than 45 μm × 24 μm. The back reflections of our SWGCs are suppressed to be below -15 dB over the wavelength range from 1260 nm to 1360 nm.