Dichroic filter for wavelength separation

摘要

An optical coupler and method of making an optical filter is disclosed wherein a compound lens having two separate movable lenses are disposed between input/output ports and a filter element, such as a dichroic filter element. The filter is tuned during assembly by varying the gap between the movable lenses. Once it is established that optimum coupling is achieved and a desired wavelength response is achieved, the two lenses are fixed in place. <IMAGE>