Reduction of semiconductor laser intensity noise by feedforward compensation: experiment and theory

The authors have recently demonstrated that an optical feedforward compensation technique can be used to reduce distortion and intensity noise in semiconductor laser transmitters. In the present work, an experimental demonstration of noise reduction by feedforward compensation and a theoretical estimation of noise limitations of the optical feedforward system are described. It is shown that in an optimized feedforward system using state-of-the-art components the relative intensity noise (RIN) can be as low as -160 dB/Hz