Abstract: An optical receiver that can receive WDM signal light in which first and second wavelength bands are combined. Within optical reception units corresponding to each channel is respectively provided tunable dispersion compensator (TDC) modules in which one wavelength band is made a design standard. When known, based on signal light channel information (wavelength, frequency, channel number) notified from outside, that signal light of the second wavelength band is being input to the receiver, then in the TDC module that performed chromatic dispersion compensation of the signal light, control is performed to shift the center frequency of the dispersion compensation range by a predetermined amount corresponding to the wavelength of the signal light. When the signal light of the first wavelength band is input, shift control of the dispersion compensation range is not performed, and the dispersion compensation range at the time of designing is maintained.

Abstract: An optical receiver that can receive WDM signal light in which first and second wavelength bands are combined. Within optical reception units corresponding to each channel is respectively provided tunable dispersion compensator (TDC) modules in which one wavelength band is made a design standard. When known, based on signal light channel information (wavelength, frequency, channel number) notified from outside, that signal light of the second wavelength band is being input to the receiver, then in the TDC module that performed chromatic dispersion compensation of the signal light, control is performed to shift the center frequency of the dispersion compensation range by a predetermined amount corresponding to the wavelength of the signal light. When the signal light of the first wavelength band is input, shift control of the dispersion compensation range is not performed, and the dispersion compensation range at the time of designing is maintained.

Abstract: An optical transmission device which efficiently suppresses variations among loss levels in optical fiber transmission, and improves quality of optical transmission. A WDM port is connected to an optical transmission line, and functions as a port for transmission and reception of a wavelength-multiplexed signal. A wavelength multiplex/demultiplex unit has optical filters which are daisy-chain connected, and realize a loss characteristic weighted at respective wavelengths in correspondence with a wavelength-dependent loss characteristic of the optical transmission line. Each of the optical filters has a function of a band-pass filter and an identical insertion loss.

Abstract: The invention relates to a method of activating an optical communication system comprising a plurality of optical amplifiers having an optical amplifier, between optical transmission lines in which wavelength-division multiplex optical signals are transmitted. The method comprises steps of: generating a desired slope in a desired wavelength range of a gain wavelength curve of the optical amplifier; adjusting an output of the optical amplifier to a desired output level; performing the above two steps in a plurality of optical repeater stations, the steps being carried out in sequence from the first to the last optical repeater stations; and adjusting a level in each optical signal in the wavelength-division multiplex optical signal so as to have substantially constant optical signal-to-noise ratios in the optical signals to be received. Activating the optical communication system according to this procedure allows proper execution of gain slope compensation, output control, and pre-emphasis control.

Abstract: The invention relates to a method of activating an optical communication system comprising a plurality of optical amplifiers having an optical amplifier, between optical transmission lines in which wavelength-division multiplex optical signals are transmitted. The method comprises steps of: generating a desired slope in a desired wavelength range of a gain wavelength curve of the optical amplifier; adjusting an output of the optical amplifier to a desired output level; performing the above two steps in a plurality of optical repeater stations, the steps being carried out in sequence from the first to the last optical repeater stations; and adjusting a level in each optical signal in the wavelength-division multiplex optical signal so as to have substantially constant optical signal-to-noise ratios in the optical signals to be received. Activating the optical communication system according to this procedure allows proper execution of gain slope compensation, output control, and pre-emphasis control.

Abstract: An optical power monitor device capable of monitoring optical power with the influence of optical crosstalk eliminated, and an optical amplifier and an optical transmitter each having the monitor device. The monitor device is applied to a light source for outputting first and second beams, for example. The first beam is divided into first and second branch beams by a beam splitter. The first branch beam is supplied to a first photodetector. The first photodetector outputs a first signal having a level corresponding to the power of the first branch beam. The second beam from the light source is supplied to a second photodetector. The second photodetector outputs a second signal having a level corresponding to the power of the second beam. The first and second signals are supplied to a first subtracter. The first subtracter outputs a first error signal corresponding to the difference between the first and second signals. The first signal and the first error signal are supplied to a second subtracter.