Monireh Moayedi Pour Fard

Towards a centralized controller for silicon photonic MZI-based interconnects

An FPGA-based centralized controller for a low-port 4×4 SiP multi-stage MZI-based switch is experimentally investigated with 10 Gb/s payload data. Packet contention resolutions and scheduling latencies are studied.

High-speed grating-assisted all-silicon photodetectors for 850 nm applications

This paper presents the design, fabrication, and measurement results of a novel lateral p-i-n silicon photodetector (Si-PD) for 850 nm in a silicon-on-insulator (SOI) platform. In the proposed photodetector, the incident light is directed horizontally using a grating coupler, significantly increasing optical absorption in the depletion area thereby increasing the PDs responsivity. The measurement results show that the grating coupler increases the responsivity by 40 times compared with the Si-PD without a grating coupler. The grating-assisted Si-PD with 5µm intrinsic width has a responsivity of 0.32 A/W and a dark current of 1 nA at 20 V reverse-bias voltage. Further, it shows an open eye diagram for 10 Gb/s PRBS‑31 non-return-to-zero on-off keying (NRZ-OOK) data and has a 3-dB bandwidth of 4.7 GHz at this bias voltage. In addition, the design parameters of three variations of the grating-assisted Si-PD for high-speed applications (>25 Gb/s) are presented. The optimized grating-assisted Si-PD uses a focusing grating coupler and its p-i-n diode has a 0.3 µm intrinsic width. It has a responsivity of 0.3 A/W, an avalanche gain of 6, a dark current of 2 µA, and a 3-dB bandwidth of 16.4 GHz at 14 V reverse-bias voltage that, to the best of our knowledge, is the largest 3-dB bandwidth reported for a Si-PD. As a result, it has a figure of merit (FoM) of 4920 GHz×mA/W. Further, it shows an open eye diagram of 35 Gb/s PRBS‑31 NRZ-OOK data.

A Ring-Based 25 Gb/s DAC-Less PAM-4 Modulator

A novel PAM-4 12.5 Gbaud/s inter-coupling modulator based on a Mach-Zehnder interferometer assisted ring resonator is demonstrated. The 25 Gb/s PAM-4 optical signal is generated by driving the modulator with two independent electrical signals with an amplitude of 3 Vpp at 2 V reverse bias. Reverse bias operation mode of the modulator enables achieving an electro-optic (EO) bandwidth of approximately 14 GHz without preemphasis of the electrical driving signals or equalization techniques. This configuration successfully simplifies the operation of the modulator in generating PAM-4 signals without the need for a digital-to-analog converter (DAC). Experimental results show proper generation of a PRBS data stream. The proposed modulator has a compact footprint of 0.48 mm2 with a bandwidth density of 52.08 Gb/s/mm2.

Automated characterization of SiP MZI-based switches

A testing methodology for commercial automated test equipment (ATE) conventionally used for electrical integrated circuits is developed for photonic integrated circuits. The method is assessing by efficiently characterizing a packaged low-port optical switch matrix.

A compact 25 Gb/s Mach-Zehnder assisted ring modulator

A novel 25 Gb/s ring-based PAM-4 modulator in silicon-on-insulator is presented. The reverse biased modulator is driven by two independent 3 Vp-p electrical signals at 12.5 Gb/s. It has a footprint of 0.48 mm2.