Patent ID: 6341024
Filing Date: 2002-01-22
Classification: H04B,H04J

Abstract:
A channel monitoring apparatus in a wavelength division multiplexing (WDM) system, the apparatus comprising:a plurality of diode means for transmitting optical signals having different unique wavelengths used in the WDM system; multiplexing means for multiplexing the optical signals received from said plurality of diode means; at least one amplifying means for amplifying a multiplexed signal received from said multiplexing means; demultiplexing means for demultiplexing a signal amplified by said at least one amplifying means; and channel monitoring means for extracting signals at channel monitoring points disposed between said plural amplifying means and hen monitoring existence/non-existence of each channel and detecting gains of said amplifying means with respect to each channel using arrayed waveguide grating (AWG) module, wherein said channel monitoring means comprises: a plurality of tapping coupler means each for tapping the multiplexed optical signal at a predetermined percent at said each monitoring point; optical switching means for selecting one of said monitoring points and optically switching an optical signal tapped by a relevant one of said tap coupler means; AWG means for dividing the optical signal switched by said optical switching means by channels of the WDM system; a plurality of trans-impedance circuit means for converting the electric signals converted by said detecting means into voltage values proportional to current values of said signals; channel multiplexing means for selecting one of signals converted by said trans-impedance circuit means; fourth amplifying means for amplifying the signal selected by said channel multiplexing means; analog/digital converting means for converting the signal amplified by said fourth amplifying means into a digital signal before applying it to microprocessing means; and microprocessing means for checking existence/non-existence of each channel and computing gains of said amplifying means with respect to each channel.