Tunable X-band optoelectronic oscillators based on external-cavity semiconductor lasers

摘要

Laser diodes with optical feedback can exhibit periodic intensityoscillations at or near the relaxation-oscillation frequency. We demonstrateoptoelectronic oscillators based on external-cavity semiconductor lasers in aperiodic dynamical regime tunable over the entire X-band. Moreover, unlikestandard optoelectronic oscillators, we need not employ the time-dependentoptical intensity incident on a photodiode to generate the microwave signal,but rather have the option of generating the electrical microwave signaldirectly as a voltage $V(t)$ at the laser-diode injection terminals underconstant current operation; no photodiode need be involved, thus circumventingoptical-to-electrical conversion. We achieve a timing jitter of $\lesssim 10$ps and a quality factor of $\gtrsim 2\times 10^5$ across the entire X-band,that ranges from 6.79 GHz to 11.48 GHz. Tuning is achieved by varying theinjection current $J$.