Beat note stabilization of a 10–60 GHz dual polarization Nd:YAG microchip laser through optical down conversion

In the context of radio-over-fiber and microwave photonic technologies [1], we show an optically carried frequency synthesis working in the range of 10–60 GHz using a dual-polarization microchip laser. An intracavity electro-optical crystal in the cavity turns the laser into a voltage controlled oscillator (VCO) and enables to implement an optical phase-locked loop (PLL). By taking advantage of the short cavity length of the microchip laser, a stabilization scheme at 40 GHz was demonstrated by mixing electrically the beat note to a phase locked dielectric resonator oscillator at 39.5 GHz [2]. Nevertheless, this electrical mixing approach has some limitations in terms of reachable frequencies and tunability, especially when one wants to reach the millimeter-wave range. To overcome theses difficulties, we propose here to operate a novel optoelectronic down-conversion principle before locking.