100 Gbit/s PAM-4 Linear Burst-Mode Transimpedance Amplifier for Upstream Flexible Passive Optical Networks

Next-generation passive optical networks (PONs) with upstream rates of 50 Gbit/s and beyond will require a new class of burst-mode transimpedance amplifiers (BMTIAs) that are linear to enable (digital) equalization of channel impairments. Such linear BMTIAs also enable higher-order modulation formats like 4-level pulse amplitude modulation (PAM-4). In this paper, we demonstrate operation of a novel linear BMTIA integrated together with a commercial off-the-shelf 25G-class avalanche photodiode (APD), achieving 50 Gbit/s non-return-to-zero (NRZ) operation with a sensitivity of −23.7 dBm optical modulation amplitude (OMA) and dynamic range exceeding 21.7 dB and 100 Gbit/s PAM-4 operation with a sensitivity of −15.8 dBm OMA and dynamic range exceeding 15.4 dB, both at a bit error ratio (BER) of $10^{-2}$ . In addition, fast burst-mode gain-control and balancing circuits limit loud-soft sensitivity penalties in the case of AC-coupled circuits to less than 1.3 dB. The chip was designed in a 0.13 $\mu$ m SiGe:C BiCMOS technology, has an area of 1.2 × 1.7 mm $^{2}$ and consumes between 260 mW and 310 mW. This receiver paves the way to a next-generation class of BMTIAs, supporting the ITU-T G.9804.3 Amd 1 standard.