Optical Injection-Locked Oscillator With Integrated Schottky Photodiode in 65 nm CMOS

This paper presents a fully integrated 1310 nm optical injection-locked oscillator based on Schottky photodiodes in a standard 65 nm CMOS process. The aim is to facilitate the optoelectrical integration in clock transmission, recovery, and synchronization for long-distance communication systems. This work compares N-well, P-well, and P-substrate Schottky diodes to lock a CMOS cross-coupled oscillator. The P-substrate diode is shown to have superior performance, specifically resulting in a reduction from a free-running RMS jitter of 57.9 ps to only 2.33 ps when locked. The oscillator has a tuning range from 2.86 to 3.33 GHz and a power consumption of 4.64 mW. The findings underscore the potential of fully integrated optical systems in standard CMOS to enhance long-distance communication networks.