Demonstration of Arbitrary Channel Selection Utilizing a Pulse-Injected Double Phase-Locked Semiconductor Laser

摘要

We demonstrate and characterize arbitrary channel selection utilizing both the double phase-locked and optical injection schemes experimentally. The double phase-locked scheme is realized by both optical injection and electrical modulation to the slave laser (SL) from a pulsed laser. The pulsed laser is generated by the semiconductor laser under optoelectronic feedback, which outputs repetitive pulse train with the repetition frequency controlled by the feedback delay time and feedback strength. When the SL subject to only the optical pulse injection from the pulsed laser, a broadband microwave frequency comb with amplitude variation ±5 dB in a 20 GHz range is generated. By further applying an electrical modulation to form a double phase-locked condition, a main channel can be selected accordingly. The advantages of large channel suppression ratio, system stabilization, and spurious noise reduction are obtained by using the double phase-locked technique. Moreover, by further applying an optical cw injection from a tunable laser, we demonstrate the selection of a secondary channel. A selection range of about 7.2 GHz is achieved by adjusting the cw injection strength. Average channel suppression between the main and secondary channels to the undesired channels with ratios of 41.8 and 25.9 dB are obtained, respectively. The single sideband (SSB) phase noise of -60 dBc/kHz (-90 dBc/Hz estimated) is achieved at offset frequencies of 25 and 200 kHz for the main and secondary channels, respectively. Demonstration of communication between the main and secondary channels is also demonstrated.