Fabry-perot polarization laser beam modulator

Claim 1

Apparatus for generating a polarization modulated laser beam of coherent wave energy; said apparatus comprising: a. first and second spaced mirrors, at least said second mirror being partially reflecting and partially transmissive, said first and second mirrors being positioned with respect to each other to define therebetween an optical resonant cavity at the wavelength of said coherent wave energy; b. means including an active laser medium situated within said optical resonant cavity for generating said coherent wave energy in response to a pump source being coupled to said active lasing medium; c. polarizer means situated within said optical resonant cavity for retaining within said optical resonant cavity only that component of said coherent wave energy incident thereon which has a given polarization and for ejecting from said optical resonant cavity that component of said coherent wave energy incident thereon which as a polarization in quadrature with said given polarization; d. a third mirror situated outside of said optical resonant cavity in spaced relationship with said second mirror to define therebetween a Fabry-Perot cavity at the wavelength of said coherent wave energy, with said optical resonant cavity and said Fabry-Perot cavity being optically aligned to permit coherent wave energy partially transmitted by said second mirror to move in either direction between said cavities, and e. polarization-rotating means situated in said Fabry-Perot cavity for rotating the polarization of coherent wave energy incident thereon in accordance with a modulating signal applied to said polarization-rotating means.