GENERATION AND RF PHASE-SHIFTING OF MILLIMETER-WAVE SUBCARRIERS USINGA HYBRID MODE-LOCKED MONOLITHIC SEMICONDUCTOR-LASER

A method for generation and RF phase-shifting of millimeter-wave subca rrier signals using a single monolithic semiconductor laser device is proposed and demonstrated. Under fundamental or subharmonic hybrid mod e-locking conditions, the optical cavity length of the laser is modula ted by the thermo-optic effect in the passive waveguide section. As a result, the timing of the generated 33 GHz output optical pulse train was successfully varied over 10 ps, corresponding to phase-shifts over 2.7 and 5.3 rad for 33 and 66 GHz subcarriers; respectively. The mech anism of the RF phase-shift is explained by analogy with the injection -locked electrical oscillator.