Abstract

Modulation of intracavity losses is a powerful tool for controlling the laser dynamics, e.g. for active mode-locking" and for synchronization of different lasers. In this paper we present an optical device that allows for fast modulation of the intracavity losses by external illumination. The device is designed as a nonlinear semiconductor Fabry-Perot étalon consisting of two Bragg reflectors with a center wavelength of 1064 nm at the backside and the frontside of a 5-μm-thick nonlinear medium—an InGaAs layer. The Indium content is chosen such that the bandgap energy is 1.28 eV (λ_gap = 970 nm). While the device is highly reflecting for wavelengths longer than λ_gap around 1064 nm, radiation with λ < λ_gap gener ates carriers which change the index of refraction and, therefore, the reflectivity of the device in the vicinity of a Fabry-Perot resonance.

© 2002 Optical Society of America