Optical signal channel counter and optical amplification device using the same

An optical signal channel counter, comprising:

• optical signal pulsing means, to which is inputted a multi-channel signal including a plurality of signals with mutually differing wavelengths which have been wavelength division multiplexed, for pulsing the multi-channel signal and outputting a pulse signal;
• pulse signal dispersion means, one end of which is connected to an output side of the optical signal pulsing means, for dispersing the pulse signal at each wavelength and outputting a dispersed pulse signal from another end;
• reflecting means, one end of which is connected to another end of the pulse dispersion means, for reflecting a dispersed pulse signal and outputting it back to the pulse signal dispersion means;
• optoelectronic conversion means for converting the dispersed pulse signal into an electrical signal;
• optical coupling means disposed between the output side of the signal pulsing means and said one end of the pulse signal dispersion means for outputting a pulse signal to the pulse signal dispersion means and also for outputting a dispersed pulse signal outputted from the pulse signal dispersion means to the optoelectronic conversion means;
• and
• peak number detection means for counting a number of signal channels by counting a number of peaks in a time waveform of the electrical signal,
• wherein the optical signal pulsing means is an optical switch including an element having an electro-optic effect, and
• wherein the wavelength dispersion medium is a dispersion compensation optical fiber.