Wavelength tunable monomode laser source with self-aligning external cavity

摘要

The laser includes a resonant cavity with a partially reflecting surface (231) and a dispersive orthogonal dihedral back reflector (21,29). A waveguide (23) placed within the resonant cavity and the back reflector has a plane diffraction grating (31) and a orthogonal dihedral reflector (29) whose apex (291) is parallel to the plane of the grating. It has two collimation axes intersecting at a point on the grating. The point forms a right angle, AC'D, and a constant length, AD. The grating and dihedron are moved together to remain fixed relative to each other. They are mounted on a plate which rotates about an axis centred on the point and is carried on a base which can be displaced in orthogonal directions.