Complete switching in a three-terminal Sagnac switch

Abstract

A three-terminal all-optical fiber switch based on a fiber Sagnac interferometer is described. The use of polarization components allows the construction of a switch in which the control beam and signal beam are isolated (i.e. the device is three terminal) and which is cascadable (the device output can drive its inputs). The interaction length need not be limited by the walkoff length in the fiber, as cross-splices can be made in the birefringent fiber to permit multiple passes. Contrast ratios as high as 40:1 have been demonstrated in a switch driven by an amplified laser diode.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>