Low-Noise Balanced Photoreceiver With InP-on-Si Photodiodes and SiGe BiCMOS Transimpedance Amplifier

A photoreceiver consisting of indium phosphide (InP) balanced photodiodes (PD) on Si ₃ N ₄ waveguides and a transimpedance amplifier (TIA) fabricated in a silicon germanium (SiGe) BiCMOS process is demonstrated. The InP PDs, heterogeneously integrated on a silicon substrate, achieve external (internal) responsivities of 0.75 (0.9) A/W, bandwidths of 4 GHz, and common mode rejection ratios (CMRR) of greater than 40 dB when illuminated differentially. The TIA achieves 74 dBΩ of transimpedance gain with a 1 dB peak, a bandwidth of 3 GHz, and a low equivalent input noise current density of 7.2 pA/√{Hz} when loaded with a C _PD of 380 fF. The full photoreceiver achieves high conversion gain of more than 2 kV/W up through 2 GHz, and a low NEP of 8 pW/√{Hz} up through 1.6 GHz. The photoreceiver optical CMRR is measured to be 36 dB.