Patent ID: 8401397
Filing Date: 2013-03-19
Classification: H04B,H04J

Abstract:
1. An optical reception device comprising: a filtering unit that receives input light of predetermined power, filters the input light by use of filter characteristics where the degree of attenuation of the power of an optical signal of predetermined frequency is lower than the degree of attenuation of the power of an optical signal of another frequency, and supplies an output light; a determining unit that compares a value relevant to the power of the output light supplied by the filtering unit, with a threshold, and determines whether the input light contains signal light; and a control unit that controls the filtering characteristics of the filtering unit such that the filtering unit supplies a first output light and a second output light one after the other, the first output light has been filtered using filter characteristics where the predetermined frequency is the same as the frequency of the signal light, and the second output light has been filtered using filter characteristic where the predetermined frequency is different from the frequency of the signal light; wherein the determining unit compares a power difference between the first and second output lights supplied one after the other by the filtering unit through the control exerted by the control unit, with the threshold, and determines whether the input light contains signal light.