Thin-film filter-based wavelength division multiplexers/demultiplexers in an angle-multiplexed architecture

Abstract

This paper shows how an angle multiplexing concept permits one thin-film filter (TF) to multiplex or demultiplex N wavelength optical beams, leading to cost-effective wavelength division multiplexers/demultiplexers (MUXs/DeMUXs). Our first TF-based wavelength MUX/DeMUX structure is arranged in a reflective design in which only the λ N wavelength optical beam cannot be recombined into the main channel. Fully multiplexing and demultiplexing operations can be accomplished by using our transmissive TF-based wavelength MUX/DeMUX architecture. Experimental proof of concept for our reflective TF-based wavelength MUX/DeMUX structure using one TF, a triple fiber-optic collimator, and an optical circulator separates two wavelength optical beams with their channel spacing of 0.8 nm from the main channel. In this case, measured optical losses of 0.67 dB, 1.66 dB, and 2.59 dB are obtained for the first, the second, and the remaining wavelength optical beams, respectively. Optical crosstalk and polarization dependent loss of < -18 dB and < 0.08 dB are also investigated, respectively.