FREQUENCY TUNEABLE LASER DEVICE

摘要

A frequency tuneable or chirped laser device is described that comprising a laser cavity formed from a plurality of optical components. The optical components comprise a laser source (20, 180, 222, 240) for generating a beam of light, a spectral tuning element (28, 42, 188, 230, 244, 300) and one or more further optical components (22, 24, 26, 30, 32, 64, 60, 184,194,195,198, 220, 232, 234, 242, 246, 248) for directing the beam of light on to the spectral tuning element (28, 42, 188, 230, 244, 300). At least one of the plurality of optical components (34, 64, 195, 232, 242) is moveable in a first degree of freedom (34;R;250); such movement simultaneously altering the effective optical path length of the laser cavity and the tuning frequency of the spectral tuning element (28, 42, 188, 230, 244, 300). The effective optical path length and the tuning frequency of the device are substantially insensitive to any movement of said at least one moveable optical component (34, 64, 195, 232, 242) in degrees of freedom other than the first degree of freedom. This provides frequency tuning in which mode hopping is suppressed.