Modulated infrared fibre=optic signal detector - has photodetector receiving reference beam, identical to signal carrier, through cube of nonlinear interaction medium receiving object beam

摘要

The detector overcomes the problem of signal distortion when transmitted over long distances using, pref., infrared radiation and has a photodetector (54) with an optical collector (53) which receives a reference beam, serving also as the signal carrier, from a laser source. The beam is received through a cm cube of non-linear indice interaction medium (5) of monocrystal. The cube also receives on a face at right angles to the reference beam an object beam which is a signal modulated and transmitted carrier beam identical to the reference beam. In an interrogator-responder system the interrogator has a laser source (62) in which the beam is split, one part forming the reference beam for the detector and the other part being modulated, transmitted to the responder where it is modulated and returned to serve as the object beam.