OPTICAL CHANNEL MONITOR

摘要

An optical channel monitor is provided that sequentially or selectively filters an optical channel(s) (11) of light from a (WDM) optical input signa l (12) and senses predetermined parameters of the each filtered optical signal (e.g., channel power, channel presence, signal-noise-ratio). The OCM (200) i s a free-space optical device that includes a collimator assembly (224), a diffraction grating (214) and a mirror (202). A launch pigtail (220) emits into free space the input signal through the collimator assembly (224) and onto the diffraction grating (214), which separates spatially each of the optical channels (11) of the collimated light, and reflects the sep arated channels of light onto the mirror (202). The mirror reflects the separated light back to the diffraction grating (214), which reflects the channels of light back through the collimating lens. The lens focuses each separated channel of light (.lambda.1 - .lambda.N) at a different focal point in space . One of the optical channels (11) is focused onto a receive pigtail (204), which then propagates to a photodetector (206). A pivoting mechanism (201) pivots the mirror about a pivot point (203) to sequentially or selectively focus each optical channel (11) to the receive pigtail (204). A position sensor detects the displacement ofthe mirror. The position sensor comprises additional mirror (210, 212) mounted adjacently the grating (214). These mirrors deflect light reflected from the scanning mirror (202) into the pigtail (242) and provide there by start and stop reference signals for a sc an cycle of the OCM.