Amplitude noise reduction in semiconductor lasers with weak, dispersive optical feedback
We present the theory and measurements of the amplitude noise spectrum from a semiconductor laser with weak optical feedback (Pfb/Pout ~10^-6) from an external cavity containing an element of dispersive loss. The laser noise is found to be reduced over most of the low-frequency spectrum, although an increase in the noise is observed at frequencies corresponding to multiples of the external-cavity free spectral range. The low-frequency noise reduction closely follows theoretical predictions, and a reduction of as much as 7 dB is measured at an injection current of 1.5 times the threshold current. The potential of this method for contributing to the production of amplitude-squeezed light is discussed.
© 1994 Optical Society of America Received March 18, 1994 The authors gratefully acknowledge support from the National Science Foundation, the Advanced Research Projects Agency, and the U.S. Office of Naval Research.