Near-Ballistic Unitraveling-Carrier Photodiode-Based V-band Optoelectronic Mixers With Low Upconversion Loss and High Operation Current Performance Under Optical IF Signal Injection

We demonstrate near-ballistic unitraveling-carrier photodiode (NBUTC-PD)-based V-band (50–75 GHz) optoelectronic (OE) mixers which can upconvert the V-band optical local-oscillator (LO) and intermediate-frequency (IF) signals. The optical LO and IF signals share a single erbium-doped optical fiber amplifier (EDFA) which means that the mixing performance of the device can be optimized by properly adjusting the ratio between the injected optical LO and IF power to the EDFA. The utilization of the strong nonlinearity of the ballistic transport of the electrons in the NBUTC-PD under a reverse bias regime means that our device achieves a low upconversion loss ( $-$6 dB) under a very high operating current (23 mA) in V-band (60 GHz). We are able to improve the operating current at the V-band over that previously reported for UTC-PD-based OE mixers. This is made possible by an increase in the optimum operating voltage from the near forward bias (0 V) to the reverse bias regime ($-$1.7 V).