Fibre gratings

A tunable laser has a fibre Bragg grating anchored at each to relatively movable fixtures and an actuator coupled to the fixtures for creating relative movement that longitudinally stretches or compresses the fibre Bragg grating. Measuring means are arranged to directly monitor a longitudinal separation between the fixtures and a microprocessor that is programmed to respond to signals from the measuring means controls the actuator to change the separation between the fixtures to tune the laser to a desired wavelength.Department of Electrical EngineeringUS6396855; US6396855 B1; US6396855B1; US6,396,855; US 6,396,855 B1; 6396855; Application No. 09/679,539U