Patent ID: 8351117

Claim:
An optical device consisting essentially of: a first polarizer having a first polarization plane, said first polarizer receiving an input light beam and generating an output beam polarized along the first polarization plane; a Faraday rotator that rotates the polarized output beam of the first polarizer to generate a first rotated beam, said rotated beam being rotated by an angle of 45 degrees relative to the first polarization plane; a Pockels cell that receives the first rotated beam from the Faraday rotator and an external input voltage to generate a second rotated beam, said second rotated beam being rotated by an angle between 0 degrees and 90 degrees relative to the first rotated beam depending on the input voltage; and a second polarizer having a second polarization plane with an angle that is 45 degrees relative to the first polarization plane, said second polarizer receiving the second rotated beam to generate a device output beam having a maximum intensity when the Pockels cell rotates the beam by 0 degrees, zero or close to zero intensity when the Pockels cell rotates the beam by 90 degrees, and variable intensity when the Pockels cell rotates the beam in a range between 0 degrees and 90 degrees, wherein said device has an isolation function that varies with the intensity of the device output beam, the isolation being a maximum when the intensity of the device output beam is a maximum.