Patent ID: 6268943
Filing Date: 2001-07-31
Classification: H04B,H04J

Abstract:
An optical signal-to-noise ratio measurer in a wavelength division multiplexed optical transmitting device, comprising:a wavelength division demultiplexer for demultiplexing an optical signal wavelength division-multiplexed from a plurality of signal channels into optical signals of the signal channels and an optical signal of a noise channel in the vicinity of the signal channels and at a different wavelength;an optical tap for separating a predetermined percentage of an optical signal of a signal channel adjacent to the noise channel among the separated signal channels;a first optical detector for detecting the optical signal separated by the optical tap and converting the detected optical signal to an electrical signal;a second optical detector for detecting the optical signal of the noise channel and converting the detected optical signal to an electrical signal; andan operating unit for obtaining an optical signal-to-noise ratio by calculating a ratio of the strength of the electrical signal received from the first optical detector to that of the electrical signal received from the second optical detector.