OPTICAL HYBRID GIVING SIGNAL RECOVERY WITHOUT RELYING ON POLARIZATION AND COHERENT LIGHT DETECTION STRUCTURE WITHOUT RELYING ON POLARIZATION

摘要

PURPOSE: To detect coherent light, independently of polarization by using a hybrid provided with a single polarized beam splitter and a single polarization plane holding coupler. CONSTITUTION: A reception message signals and a local oscillation signal are applied to a polarized beam splitter 16 as orthogonal inputs, and a pair of outputs include orthogonal components from each input signal. A polarization plane holding coupler 18 couples the pair of output signals, and a balanced receiver 14 restores a transmitted data signal, independently of polarization of the arriving message signal. By this constitution, elements which are easily affected by polarization are used as few as possible for detecting coherent light truly independently of polarization.