A 4: 1 electro-optic multiplexer/demultiplexer, which is compatible with relatively large-NA (0.25), low-loss fibers, has been constructed and tested. The device incorporates four switches on one crystal, employs collimation of the fiber emission by butt coupling, and uses a new electrode guiding structure that eliminates the need for a polarizer. The entire unit, including the 0.25-NA fibers, exhibits 15-dB total throughput loss and a 10-dB signal-to-crosstalk ratio.