Patent ID: 6262822
Filing Date: 2001-07-17
Classification: H04B,H04J

Abstract:
A monitor for monitoring a plurality of optical input channels and for monitoring energy between adjacent channels, each channel being spaced apart from an adjacent channel by predetermined inter-channel spacing, each of the plurality of channels having a different central wavelength, said monitor comprising:a tunable bandpass filter having an input end and an output end, the filter having a passband selected to pass a bandwidth less than the predetermined channel spacing while substantially blocking wavelengths outside the passband, the filter being tunable to sequentially pass wavelengths corresponding to each of the plurality of channels, and the wavelengths in the inter-channel spaces;an output terminal optically coupled to the output end of the tunable filter for receiving light that has propagated through the tunable filter;first detector means for detecting a characteristic of the light at the output terminal;a second filter having a periodic response optically coupled to the output end of the tunable filter for receiving light that has propagated through the tunable filter, the second filter being dimensioned, in accordance with the predetermined channel spacing, to pass central wavelengths in the inter-channel spaces and to substantially block central wavelengths of light corresponding to the plurality of channels; andsecond detector means, for detecting a characteristic of light that passes through the second filter.