Process of adjustment of a continuously tunable light source

Claim 1

A process of adjustment of a continuously tunable external cavity light source, said source comprising: a laser controlled by an injected current with an optical axis and a first and a second facet, the first facet having a low reflection coefficient, a diffraction grating placed on the axis of the laser, on the side of the first facet, rotatable about an axis intersecting the laser axis at right-angles, and, with the second facet of the laser, forming the external cavity, an arm rigidly connected to the grating having a mobile end which is in permanent contact with a slide plane perpendicular to the optical axis of the laser, means of fine adjustment of the slide plane with respect to the laser, the tunning of the source being achieved by a shifting of the grating, wherein: (a) an approximate adjustment is made of the rotation and position of the slide plane, (b) the grating is rotated and, simultaneously, the emissive power of the source is measured with respect to the current injected as a function of the rotation of the grating, (c) the number of emissive power jumps is counted with respect to the current injected during the rotation of the grating, each jump being given a sign depending on its direction, (d) the fine adjustment means are used in accordance with the result of the count, (e) operations (b), (c) and (d) are repeated until the count result is zero.