Abstract

Theoretical and experimental studies of a novel wavelength-division multiplexing (WDM) design employing a single fiber array, on-axial transmission focusing and collimating optics, and a Littrow reflective volume holographic grating are presented. This WDM configuration has the potential to achieve less than −1-dB insertion loss and −35-dB crosstalk for up to six channels and less than −2dB insertion loss and a − 20-dB crosstalk for up to twelve channels. A four-channel prototype in a compact geometry has been constructed utilizing a volume holographic grating with >85% efficiency and laser diodes with 3-nm nominal linewidth. Experimental results are presented. This first-of-the kind WDM is expected to have an insertion loss of less than −2 dB and crosstalk of less than −30 dB. Using multiple exposure techniques, several independent gratings can be superimposed on the same volume hologram. Utilizing this multiple exposure hologram and multiple fiber arrays, and only one single surface aspheric lens, the proposed configuration can readily be expanded to accommodate multiple wavelength windows with many channels in each window.

© 1988 Optical Society of America