4×4 Optical Switch with Polarization Selective Elements

The basic optical switch in optical interconnection networks is a 2times2 optical switch which provides two switching states: the "straight" state and the "swap" state. Several kinds of optical switch have been presented such as polarization selective elements combined with electro-optic halfwave plates. Using these basic optical switches to construct a 4times4 nonblocking interconnection network, such as Benes network and double-layer network, needs three stages of optical switches. In this presentation, a 4times4 optical switch with polarization selective elements and electro-optic halfwave plates will be proposed. In this switch, the control configurations of electro-optic halfwave plates have been changed to support all switching states of polarization selective elements. Compared with 4times4 nonblocking interconnection networks, this 4times4 optical switch has the lowest system insertion loss and the fewest required components. Its structure and connection path for different switching functions will be discussed in detail