Stabilized 1.5 microns dual-frequency laser prototype for optical generation of high purity microwave signals

The generation of optically carried microwave signals is of great interest for a wide range of fields, from long-range transmission of RF to wideband radar signal processing. Among the available generation techniques, the potentialities of optical heterodyning are firmly established. However, it leads to severe constraints in optical phase-locked loop (OPLL) design. In this paper, we report on the realization of a compact and ruggedized Er,Yb:glass DFL at 1.5 μm stabilized with three servo-loops.