Ge-on-Si Balanced Periodic Traveling-Wave Photodetector

A balanced periodic traveling-wave photodetector (BP-TWPD) on silicon-on-insulator is demonstrated for the first time. The device is composed of 8 germanium waveguide photodiodes and delivers high output powers of 8.3 dBm at 5 GHz and 2.6 dBm at 25 GHz. The internal responsivity is 0.84 A/W and the common mode rejection ratio (CMRR) is larger than 30 dB from DC to 30 GHz.