A 10/2.5-Gb/s Hyper-Supplied CMOS Low-Noise Burst-Mode TIA with Loud Burst Protection and Gearbox Automatic Offset Cancellation for XGS-PON

Abstract

The surge of internet bandwidth recently has accelerated the upgrade of the Passive Optical Network (PON) from 1.25Gb/s GPON to 10Gb/s class XGS-PON with massive volume. As a key component, the burst-mode transimpedance amplifier (BM-TIA) is required to cope with the BM data from multiple users. Previously, high performance BM-TIAs were made mostly by SiGe [1]–[3], contrasting the prospect of economics. At least three issues have hindered CMOS from being widely employed in BM-TIA compared with SiGe. 1) Noise: the relatively poor analog performance as well as limited power supply voltage from CMOS makes low noise difficult to achieve. 2) Breakdown protection: the low breakdown voltage makes CMOS much more fragile to loud bursts. 3) Fast BM response: the low supply voltage renders the CMOS biasing point delicate, which increases the complexity and duration for the circuit to recover from a burst event. Previous CMOS-TIAs [4], [5] have achieved fast BM response, but their topologies are incompatible with current TOCAN based commercial applications which can only house the analog front-end. In this work, we address the noise, breakdown, and fast BM response altogether, paving the way for CMOS to be used in commercial BM application in 10Gb/s class PON and beyond.