OPTICAL WAVELENGTH CONVERTER

摘要

A wavelength converter comprises a loop of optical fibre having an entry end (14) and an exit end (16). The entry end of the loop forms an input for a pump wavelength and the exit end forms an outlet for a converted signal. The loop is arranged to produce Stokes shifted wavelength components from a pump wavelength by Raman effect. A wavelength selective coupler (18) is provided between the entry and exit end (14, 16) of the loop. The coupler permits exit of a predetermined wanted Stokes shifted wavelength component but causes coupling of lower order Stokes wavelengths to the entry for recirculating in the loop to enhance generation of the predetermined wavelength component.