| 摘要 |
PROBLEM TO BE SOLVED: To improve deterioration of a transmission characteristic by an error between an optical signal wavelength and the transmission center wavelength of an optical multiplexer/demultiplexer by means of setting an optical signal spectrum to be symmetrical to a signal light center wave by inserting an optical filter for spectrum shaping and shaping the spectrum. SOLUTION: Optical signal transmitted to the optical fiber 10a of a wavelength multiplex signal light transmission line is demultiplexed by an optical demultiplexer 20 in an optical wavelength branch/insertion device 100a. Respective light beams are made incident on a spectrum shaping filter 51. In an optical spectrum control means 50, an optical filter controller 53 controls the transmission wavelength characteristic of the optical filter for spectrum shaping 51 so that symmetry is shown to respective wavelength light beams detected by a detector 52. When the optical signal beams of the respective wavelengths, which are spectrum-shaped, are inputted to an optical switch 60 and they are branched, they are inputted to an optical receiver 40 as reception signals. When they are inserted, the outputs of an optical transmitter 30 are set to be insertion signals. Thus, the deterioration of a transmission characteristic owing to spectrum deformation by an error between the optical signal wavelength and the transmission center wavelength of optical multiplex. |
