Patent ID: 6041151
Filing Date: 2000-03-21
Classification: G02B,G02F

Abstract:
An optical switch for switching first and second input beams linearly polarized in the same direction, comprising:a first half wave plate optically coupled to the second input beam, said first half wave plate for rotating the polarization of light incident thereto 90 degrees:a first polarizing beam displacer optically coupled to the first input beam and the output of said first half wave plate, said first polarizing beam displacer for refracting the first input beam and the output of said first half wave plate to produce a combined beam, the first input beam and the output of said first half wave plate incident to said first polarizing beam displacer displaced from each other a predetermined distance;a controllable half wave gate having a gate input port, a gate output port, a control input, a passive state and an active state, said controllable half wave gate in said passive state passing said combined beam incident to said gate input port through to said gate output port whereby the polarization of said combined beam is unchanged, said controllable half wave gate in said active state passing said combined beam incident through to said gate input port through to said gate output port whereby the polarization of said combined beam is rotated 90 degrees, a control signal present at said control input causing said controllable half wave gate to switch between said passive and said active states, said gate including a ferroelectric liquid crystal shutter,a second polarization beam displacer optically coupled to said gate output port, said second polarization beam displacer for refracting light incident thereto into first and second refracted output beams displaced from each other a predetermined distance upon exiting said second polarization beam displacer; anda second half wave plate optically coupled to said second refracted out beam, said second refracted output beam, said second half wave plate for rotating the polarization of light incident thereto 90 degrees.