Filtered optical feedback induced dynamics in semiconductor lasers

\u3cp\u3eAn experimental and numerical demonstration of filtered optical feedback (FOF) induced frequency dynamics in semiconductor lasers were discussed. A filter introduces a controllable nonlinearity in the feedback system, and its influence on the laser dynamics can be manipulated via the filter's bandwidth, and its detuning from the laser frequency. It was also demonstrated that by spectral filtering of the delayed optical feedback into a diode laser it is possible to induce controlled oscillations in the instantaneous frequency of light from laser by careful choice of the filter bandwidth qnd DL frequency. The results suggested that the frequency oscillator is a delay induced dynamical device.\u3c/p\u3