Abstract

The technique of applying a low level of optical feedback to stabilise a diode laser to the resonant frequency of an external cavity has been applied to various cavity configurations eg [1,2,3] in order to obtain tunable narrow-bandwidth sources for atomic spectroscopy. In the case of a ring cavity the required feedback is generally achieved via some internally generated coupling of the forwardrunning mode of the cavity into a counterpropagating mode, with appropriate control of the feedback phase. However for some diode- cavity combinations the level of feedback achieved is not in a suitable range for reliable stabilisation of the laser diode [4].

© 1996 Optical Society of America