| 摘要 |
The optical spectrum analyser analyses an incident beam(101) and includes: - addressing means(1) for the incident(101); - a diffraction network(2) fitted with parallel lines(40) receiving and diffracting a first time the beam(103,104); - a dihedral reflector(3), for receiving the beam(105,106) diffracted once and reflecting it towards the network(2), the network(2) diffracts the beam(107,108) second time; - an adjuster(4) which by rotation of the dihedral reflector permits selection of the measured wavelengths; - a receiver unit(5) for the selected beam(112); - at least a photo-detector(6) connected to the receiver(5), is used to detect the received beam(112) and; - a processing unit(7) connected to the photodetectors(6) and to the adjuster(4) produces a spectrum of the beam. The system also includes: - a polarising separator(11) inserted between the addressing and receiving means(1,5) on the one hand and the diffraction network(2) on the other, which splits the incident beam(101) into a first and second secondary parallel beams(102,104) of polarised light along directions respectively parallel and perpendicular to the lines(40) of the network(2) and; - a lambda /2 strip(12) placed on the path of the first secondary beam(102) so as to give it a polarisation direction perpendicular to the lines(40) of the network(2), and the network(2), the dihedral reflector(3) and the separator(11) are positioned so that the network(2) diffracts a first time the secondary beams(103,104), the reflector(3) exchanges their directions, the network(2) diffracts them a second time and the separator(11) recombines them into the same principal beam(112) sent to the receiver(5).
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