Two Diode Lasers Simultaneously Optically Locked by Orthogonal Polarizations of a Monolithic Confocal Cavity

We demonstrate two self-injection locking extended cavity diode lasers (ECDLs) using resonant optical feedback independently from s- and p-polarizations of a monolithic folded Fabry–Perot confocal cavity (MFC). The relative frequency shift of adjacent axial modes of s resonance and p resonance of MFC is around 1.030 GHz. Beat note measurements between the two ECDLs are performed and present a relative linewidth of 4 kHz. With the help of a narrow-linewidth reference laser, the linewidth of s-component and p-component ECDLs are measured to be about 32 kHz and 40 kHz, respectively.