STABILIZATION OF MILLIMETER-WAVE FREQUENCIES FROM PASSIVELY MODE-LOCKED SEMICONDUCTOR-LASERS USING AN OPTOELECTRONIC PHASE-LOCKED LOOP

We report the use of an optoelectronic phase-locked loop to stabilize the pulsation frequency of a three-section, passively mode-locked quan tum well laser diode at 41 GHz. It is shown that the free-running mode -locked signal, with a radio frequency (RF) linewidth of 770 kHz, can be stabilized to the linewidth of a reference RF oscillator (< 1 kHz). The stabilized mode-locked signal has a phase noise of -70 dBc/Hz at 370 kHz offset. Tracking of the mode-locked signal to the external ref erence RF oscillator is maintained over 11 MHz. This is, in effect, an actively mode-locked laser source at 41 GHz.