A 1.25-gb/s burst-mode receiver for GPON applications

This paper presents a 1.25-Gb/s burst-mode receiver (BMRx) for upstream transmission over gigabit passive optical networks (G-PONs). The dc-coupled receiver uses a unique arrangement of three limiting amplifiers to convert the bursty input signal to a current mode logic output signal while rejecting the dc offset from a preceding transimpedance amplifier. Peak detectors extract a decision threshold from a sequence of 12 successive nonreturn-to-zero (NRZ) 1´s and 12 successive NRZ 0´s received at the beginning of each packet. Automatic compensation of the remaining offsets of the BMRx is performed digitally via digital-to-analog converters. The chip was designed in a 0.35-μm SiGe BiCMOS process. The receiver contains an APD with a gain of 6 and a transimpedance amplifier and shows a sensitivity of -32.8 dBm and a dynamic range of 23.8 dB. A sensitivity penalty of 2.2 dB is incurred when a packet with average optical power of -9 dBm precedes the packet under consideration, the guard time between the packets being 25.6 ns. The BMRx includes activity detection circuitry, capable of quickly detecting average optical levels as low as -35.5 dBm. The performed measurements prove that the receiver meets the G-PON physical media dependent layer specification defined in ITU-T Recommendation G.984.2.