| 摘要 |
<p>The present invention provides for improved add/drop WDM multiplexers in fiberoptic networks. One embodiment has two cascade-connected WDM couplers (34, 35) with each coupler having a filter at a selected wavelength μi. Light received from one fiber section is passed to one or the other fiber sections according to wavelength by operation of the wavelength-dependent filter. The two WDM couplers act as an add/drop WDM multiplexer provide improved crosstalk isolation because light is effectively filtered twice by reflection. Likewise, a compact add/drop WDM multiplexer can be created with a WDM coupler structure having two sets of aligned optical fiber sections separated by a first collimating lens (72), a wavelength-dependent filter (73) at a selected wavelength μi, and a second collimating lens (74).</p> |
