Patent ID: 6167066
Filing Date: 2000-12-26
Classification: H01S

Abstract:
A linearly-polarized, single frequency fiber laser, comprising:a pump laser that generates an optical pump signal;an optical fiber arranged to receive said optical pump signal, said optical fiber having a first transverse axis and a second transverse axis and at least a portion of said optical fiber doped with laser-active ions so that said optical fiber exhibits photon gain in response to said optical pump signal;a first grating in said optical fiber that is configured with a first period;a second grating in said optical fiber that is configured with a second period;a first segment of said optical fiber which has a first refractive index along said first transverse axis and a second refractive index along said second transverse axis, said first segment positioned to at least partially include said first grating; anda second segment of said optical fiber which has a third refractive index along said first transverse axis and a fourth refractive index along said second transverse axis, said second segment positioned to at least partially include said second grating;wherein:said first refractive index and said first period are chosen to generate a first optical signal reflectance at a first optical frequency;said second refractive index is chosen to generate, with said first period, a second optical signal reflectance at a second optical frequency;said third refractive index and said second period are chosen to generate a third optical signal reflectance substantially at said first optical frequency; andsaid fourth refractive index is chosen to generate, with said second period, a fourth optical signal reflectance at a fourth optical frequency that is different from said second optical frequency;said first and third signal reflectances providing feedback at said first optical frequency which cooperates with said photon gain to generate a laser signal having a polarization substantially aligned with said first transverse axis while said second and fourth signal reflectances fail to provide feedback that is necessary to generate a laser signal having a polarization substantially aligned with said second transverse axis.