A 22-Gb/s Time-Interleaved Low-Power Optical Receiver With a Two-Bit Integrating Front End

Abstract

This article presents the implementation of a novel 22-Gb/s energy-efficient optoelectronic receiver architecture in 65-nm CMOS for short-reach optical communication. The receiver incorporates four sub receivers with a two-bit integrating resettable front-end in each sub receiver. The inputs to two of the four sub receivers are optically delayed by one bit and two complementary quarter-rate clock phases are used to completely recover the data. The two-bit integrating low-bandwidth front end replaces the full-bandwidth transimpedance amplifier used in conventional optoelectronic receivers, resulting in improved energy efficiency. The low-bandwidth operation is enabled by using a capacitor at the input and by amplifying the two-bit integrated voltage with low-bandwidth voltage gain stages that require a bandwidth of only 35% of the operating data rate. The receiver performs a 1:4 demultiplexing operation by only using two quarter-rate clock phases instead of the four phases that are conventionally used in a quarter-rate clocking system. This clocking scheme reduces complexity while maintaining the same timing margin of the quarter-rate systems. This two-clock phase system is enabled by optical delay lines and splitters. The receiver is experimentally validated with a 1550-nm photodetector array wire bonded to the four inputs. The electronic part of the receiver achieves error-free transmission (BER < 10 −12) at 22 Gb/s with an energy efficiency of 1.43 pJ/bit and an average sensitivity of −7.8 dBm (or −6.2 dBm optically modulated amplitude) with a 1.09-V supply.

Optimal Optical Receivers in Nanoscale CMOS: A Tutorial

“…Unlike FFE-based optical receivers that enhance noise (see (12)), the DFE loop has no impact on the output referred noise of the TIA. The SNR WC is calculated using (10) and plotted in Fig. 4 (c) versus f 3dB /f baud for both a 2-tap and infinite length DFE.…”

Distance-aware Approximate Nanophotonic Interconnect

“…Where 𝑃 𝑠 is the optical power injected from source core (in dBm) and 𝑃 𝑑 is the optical power received at the destinations core (dBm). 𝑃 𝑑 depends on the targeted BER at the destination photodetector [37]. In this work, we defined the BER for approximate and accurate communications using system level simulation results, as detailed in section 4.…”

“…Second, we aim to define the hop count from which long-range communications start. We first assume minimum optical power of -8 𝑑𝐵𝑚 and -12 𝑑𝐵𝑚 for accurate and approximate data reception respectively [37]. We assume 0.02 𝑑𝐵 MR through loss, 0.7 𝑑𝐵 MR drop loss, [42] an FSR of 8𝑛𝑚 and a MR quality factor of 20, 000 [43].…”