Patent ID: 6870973

Claim:
A depolarizer for converting a linearly polarized laser output having multiple longitudinal modes into light in which the intensity is substantially equally divided between orthogonal polarization states comprising: a first segment L 1 of polarization maintaining optical fiber optically coupled to receive the linearly polarized laser output, said first segment having orthogonal birefringent axes, one of said orthogonal birefringent axes being oriented at substantially zero degrees relative to a plane of polarization of the laser output, said first segment having a length L 1 equal to about: λ 2 /(4.Δλ.Δn 1 ); a second segment L 2 of polarization maintaining optical fiber optically coupled to the first segment of polarization maintaining fiber, said second segment having orthogonal birefringent axes oriented at substantially 45 degrees to the orthogonal birefringent axes of the first segment, said second segment having a length L 2 equal to about: λ 2 /(2.Δλ.Δn 2 ); where λ is the laser diode wavelength, Δλ is the laser longitudinal mode spacing, and Δn 1 is the birefringence of the polarization maintaining fiber of the first segment of polarization maintaining fiber, and Δn 2 is the birefringence of the polarization maintaining fiber of the second segment of polarization maintaining optical fiber.