A 12.5 Gb/s 1.93 pJ/Bit Optical Receiver Exploiting Silicon Photonic Delay Lines for Clock Phases Generation Replacement

Abstract

This article describes a high-speed optoelectronic receiver implemented in 65 nm CMOS technology. The receiver utilizes only two clock phases instead of the four conventionally used in a quarter-rate clocking system. This two-clock phase system is enabled by a passive silicon photonic split and delay structure that eliminates the need for a quadrature clock phase generator and all the associated buffers. Moreover, the outputs of the receiver are demultiplexed which further helps reducing power consumption in the digital part of the system. The receiver also employs inter-stage AC coupling and is mounted on a high-speed printed circuit board (PCB). The impact of AC coupling and PCB parasitics is investigated. The functionality of the receiver is validated by highspeed optical measurements. The receiver achieves an error-free transmission (BER < 10−12) up to a data rate of 12.5 Gb/s with an energy efficiency of 1.93 pJ/bit and sensitivity of −4 dBm from a 1 V supply.