Mode-hop-free fine tuning of an external-cavity diode laser with an intracavity liquid crystal cell

Abstract

A planar nematic liquid crystal (NLC) cell is incorporated into a Littman-type external cavity as the wavelength-turfing device for a semiconductor laser diode. By varying the driving voltage of the NLC cell and laser diode bias current simultaneously, we demonstrate single-mode oscillation and mode-hop-free tuning over 19.2 GHz at 775 nm. The result is in good agreement with the theoretical predictions. (C) 2004 Optical Society of America.