A 4×50Gb/s NRZ 1.5pJ/b Co-Packaged and Fiber-Terminated 4-Channel Optical RX

This paper presents a 4-channel co-packaged optical RX that integrates a photo diode array, fiber termination and a transimpedance amplifier front end (TIA-FE) IC on the same package as an RX data-path IC. To achieve high sensitivity, the TIA-FE employs bandwidth extension and in-band group delay compensation techniques that are co-optimized with a 1/4-rate 2-tap feed-forward equalizer (FFE) in the RX data-path. A StrongArm latch that improves noise variance by 3.5x for iso-power is introduced. Modulated by its VCSEL-based optical TX counterpart, the optical RX demonstrates 4×50Gb/s NRZ at 1.5pJ/b with BER<10⁻¹² and a sensitivity of -6dBm.