Optical signal quality supervisory device

摘要

The present invention has an object to obtain an optical signal quality supervisory device that supervises the quality of an optical signal simply, efficiently and with high accuracy without inviting an increase in cost, an increase in circuit scale and increase in power consumption. The bit rate of the optical supervisory channel is made lower than the bit rate of the optical main channel that is transmitted over an optical communication system. Also, the optical supervisory channel is made up of an SOH (section over head) frame to detect an error of the BIP (bit interleaved parity) byte of SOH, thereby supervising the quality of the optical communication system, in particular, the light wave network. The optical communication system comprises a wavelength multiplex system that relays at multiple stages optical amplifiers which amplify a plurality of main optical channels different in wavelength. The optical supervisory channel receiving means includes at its reception end a band pass filter, the pass band of which is set in accordance with the gain of the optical amplifiers.