OPTICAL WAVELENGTH-DIVISION MULTIPLEXING AND DEMULITPLEXING BY USING A COMMON OPTICAL BANDPASS FILTER FOR ADDING, DROPPING, OR EXCHANGING ONE OR MROE CHANNELS

摘要

Techniques for using the same optical bandpass filter to add, drop or exchange a WDM channel in a WDM device. The device includes a first lens (150), a second lens (160) and an optical bandpass filter (170). The first lens (150) and the second lens (160) are spaced from each other and define a common optical axis. The optical bandpass filter (170) is located between the first and the second lenses (150, 160). There are first and second fiber ports (110, 140) located at a first focal plane (152) and symmetrically displaced from the common optical axis in a plane. The device further includes third and fourth fiber ports (130, 120) at a second focal plane (162) and symmetrically displaced from the common optical axis in the same plane.