Patent ID: 6163396
Filing Date: 2000-12-19
Classification: H01S

Abstract:
A wavelength converter comprising:(A) a first loop of optical fiber having an entry end and an exit end, the entry end of said first loop forming an input for a pump wavelength and the exit end of said first loop forming an outlet for a converted signal, said first loop arranged to produce Stokes shifted wavelength components from a pump wavelength by Raman effect; and(B) a first wavelength selective coupler between the entry and exit ends of said first loop, said first coupler permitting exit of a first predetermined wanted Stokes shifted wavelength component and causing coupling of lower order Stokes shifted wavelength(s) to the entry end of said first loop for recirculation in the loop to enhance generation of the first predetermined wanted wavelength component;(C) said optical fiber extending from the entry and exit ends of said first loop to form a second loop of optical fiber having an entry end which forms a loop input for the pump wavelength and an exit end forming a loop output for a converted signal; and(D) a second single wavelength selective coupler provided between the entry and exit ends of the second loop, said second coupler permitting exit of a second predetermined Stokes shifted wavelength component and causing coupling of the other wavelength components to the entry end of the second loop for recirculation through the first and second loops to enhance generation of the second predetermined wavelength component.