All-optical gain optoelectronic oscillator based on a dual-frequency integrated semiconductor laser: potential to break the bandwidth limitation in the traditional OEO configuration.

A novel photonic method, to the best of our knowledge, to generate high-frequency micro/millimeter-wave signals based on the optoelectronic oscillator (OEO) with all-optical gain is proposed in this paper. The core device is the monolithically integrated dual-frequency semiconductor laser (MI-DFSL), in which the two DFB laser sections are simultaneously fabricated on one chip. Attributing to the combined impact of the photon-photon resonance effect and the sideband amplification injection locking effect, one widely tunable microwave photonic filter with a high Q value and narrow 3-dB bandwidth can be realized. In this case, the generated microwave signals would largely break the limitation in bandwidth once making full use of the optical amplifier to replace the narrow-band electrical amplifiers in traditional OEO configuration to provide the necessary gain. No additional high-speed external modulator, high-frequency electrical bandpass filters or multi-stage electrical amplifiers are required, highly simplifying the framework and reducing the power consumption. Moreover, this simple and compact structure has the potential to be developed for photonic integration. In the current proof-of-concept experiment, microwave signals with wide tuning ranges from 14.2 GHz to 25.2 GHz are realized. The SSB phase noises in all tuning range are below -103.77 dBc/Hz at 10 kHz and the best signal of the -106.363 dBc/Hz at 10 kHz is achieved at the frequency of 17.2 GHz.