Patent ID: 7518786

Claim:
An optical harmonic frequency conversion module comprising: a semiconductor fiber laser generating a substantially linearly polarized light output; a non-linear crystal waveguide device for converting the light output from the semiconductor fiber laser having a first frequency into an output light having a second frequency; and an optical fiber link for coupling the substantially linearly polarized light output from the semiconductor fiber laser into the non-linear crystal waveguide device, the optical fiber link comprising a birefringent optical fiber having a fast axis and a slow axis orthogonal thereto, the optical fiber link further comprising a first segment L 1 optically coupled to a second segment L 2 such that a fast axis of L 1 is coupled to a slow axis of L 2 , and wherein 2 ⁢ π × L × Δ ⁢ ⁢ n ⁡ ( T ) λ < 2 ⁢ π where L is the difference L 1 −L 2 , T is the operating temperature range, λ is the wavelength, and Δn(T) is the PM fiber birefringence which is temperature dependent, such that an output of the non-linear crystal has less than one power oscillation within a selected operational temperature range.