Feedback control of the intensity-noise of injection locked lasers

We demonstrate close to optimum control of the intensity noise by laser-by combining the techniques of laser injection locking and negative electronic feedback. The greatly increased stability of the electronic feedback loop from the output of the slave laser to its pump source that can be obtained by injection locking the slave laser is used to strongly suppress the intensity noise of this laser. We simultaneously use the injection locked output to negatively feed back to an amplitude modulator in the master laser beam and, with both control loops running, we can demonstrate intensity noise suppression of the composite system to within 1 dB of the theoretical limit at 5 kHz. (C) 1998 Elsevier Science B.V.