DC-220 GHz well-impedance matched ultra-broadband photodetector for high symbol rate advanced optical fiber...

We report an ultra-broadband uni-travelling carrier photodetector (PD) operated from DC to beyond 220 GHz with a well-impedance-matched circuit. A 3-dB bandwidth of over 220 GHz was measured and was expected to be as high as 260 GHz in the simulation. A high 1-dB power compression level (P1 dB) of -5.4 dBm at 200 GHz was measured. In the high-baud-rate signal detection demonstration, a clear eye diagram and low bit error rate were measured at 100 Gbaud (NRZ). The potential for 300-Gbaud signal detection was revealed by a simulation as converted from the measured frequency response. To enhance the PD responsivity, an integrated PD module with a semiconductor optical amplifier (SOA) yielded a high responsivity of 16.2 A/W. The PD design, characteristics, and broadband signal detection were discussed.