WDM LIGHT TRANSMISSION SYSTEM, WAVELENGTH DISPERSION MEASURING METHOD, OPTICAL TRANSMITTING DEVICE, AND OPTICAL RECEIVING DEVICE

摘要

PROBLEM TO BE SOLVED: To measure wavelength dispersion of a optical fiber in service.

SOLUTION: The optical transmitting device 10 transmits data D1-Dn by frequency-modulated optical carriers having different wavelengths, multiplexes n lights of phase-modulated signal lights, and then output to an optical fiber 12. A separation device 30 separates the lights input from the optical fiber 12 into light signals having different wavelengths. Each light detector 32-1-n converts each of the light signals having different wavelengths to electrical signals. Each clock extraction device 34-1-n extracts clock components of the data D1-Dn from outputs corresponding to the light detector 32-1-n. Each data reproduce device 36-1-n reproduces the data D1-Dn from outputs of the light detector 32-1-n. A phase locked loop (PLL) circuit comprising oscillators 38-1-n, multipliers 40-1-n, and loop filters 42-1-n extracts FM modulate components from outputs of the circuits 34-1-n. FM component measuring devices 44-1-n measure amplitudes and frequencies of the FM modulate components, and calculation devices 46-1-n calculate wavelength dispersion values for each wavelength.

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