| 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 signal 12 and senses predetermined parameters of the each filtered optical signal (e.g., channel power, channel presence, signal-noise-ratio). The OCM 10 is a free-space optical device that includes a collimator assembly 15, a diffraction grating 20 and a mirror 22. A launch pigtail emits into free space the input signal through the collimator assembly 15 and onto the diffraction grating 20, which separates spatially each of the optical channels 11 of the collimated light, and reflects the separated channels of light onto the mirror 22. A lambd/4 plate 26 is disposed between the mirror 22 and the diffraction grating 20. The mirror reflects the separated light back through the lambd/4 plate 26 to the diffraction grating 20, which reflects the channels of light back through the collimating lens 18. The lens 18 focuses each separated channel of light (lambd1-lambdN) at a different focal point in space. One of the optical channels 11 is focused onto a receive pigtail 28, which then propagates to a photodetector 30. A pivoting mechanism 34 pivots the diffraction grating 20 or mirror 22 about a pivot point 36 to sequentially or selectively focus each optical channel 11 to the receive pigtail 28. A position sensor 42 detects the displacement of the diffraction grating 24 or mirror.
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