A new master-slave semiconductor laser configuration for the generation of sub-shot noise light

Generation of sub-shot noise light with a developed master-slave semiconductor laser configuration is described. A vertical-cavity surface-emitting laser (VCSEL) is used as master laser instead of an external cavity laser or a dye laser. The whole apparatus works at room temperature rather than cryogenic temperatures. The slave laser is a conventional edge emitting single quantum well laser with a high quantum efficiency of 1 W/A. Both lasers emit light with wavelengths around 845 nm. The separation of master and slave output is realized using a Faraday rotator (ROT) and a polarizing beam splitter (PBS) such that the master output is reflected at the beam splitter while the slave output, the polarization of which is rotated by 90 degrees by the Faraday rotator relative to the master output, is transmitted. An optical isolator (ISO) prevents stray light from the beam splitter from entering the master laser. Movable beam splitters allow to direct all of the slave output to a detector or reflect part of it for spectral characterization using an optical spectrum analyzer (OSA) and a Fabry Perot (FP).