Electro-optical fiber modulation in a Sagnac interferometer

The linear electro-optical effect was induced in optical fibers by thermal poling. A Sagnac all-spliced fiber loop was constructed incorporating an electro-optical fiber used as a phase modulator at 1.5 μm and stable switching was obtained. A rise time of ∼40 ns was obtained, and signals <2 V generated a measurable optical response.