Patent ID: 6832022
Filing Date: 2004-12-14
Classification: G02B

Abstract:
A rectangular response optical filter for partitioning a limited spectral interval in a light flux with wide spectrum comprising:an input optical fibre having one end, a grating-reflector assembly in Littman-Metcalf configuration, a converging collimation optical system at whose focal point is located the end of the input fibre, a converging focusing optical system placed between the grating and the reflector, at least one reflector placed in the focal plane of the focusing optical system which has a dimension limited in the dispersion plane whereas the position and the limited dimension of the reflector in the dispersion plane determine the partitioned spectral interval, characterized in that it comprises a polarisation separator placed between the input fibre and the grating and generating two elementary light beams parallel and polarised orthogonally with respect to one another, whereas a plate &lgr;/2 is placed on one of the elementary beams in order to generate two elementary parallel beams polarised in a direction perpendicular to the lines of the grating, whereas the reflector of Littman-Metcalf configuration sends back each elementary beam onto the path and in opposite direction in relation to one another.