Patent ID: 6310899
Filing Date: 2001-10-30
Classification: H01S,H04B

Abstract:
Apparatus for converting optical energy within an optical communications system including a source of optical energy having an input wavelength .lambda..sub.p, wherein the optical energy is converted to an output wavelength .lambda..sub.n that is greater than the input wavelength .lambda..sub.p, wherein said apparatus comprises:an optical transmission medium coupled to the source of optical energy and having an input region and an output region;at least one pair of gratings formed in said optical transmission medium that defines optical cavities for radiation of optical energy at said output wavelength .lambda..sub.n,a first reflective grating formed in the output region of said optical transmission medium at a wavelength that provides maximum reflection of optical energy at a first input wavelength .lambda..sub.p1.a second reflective grating formed in the output region of said optical transmission medium at a wavelength that provides maximum reflection of optical energy at a second input wavelength .lambda..sub.p2, wherein at least one of the first and second input wavelengths differs from the input wavelength .lambda..sub.p,wherein at least one pair of the gratings is written in said optical transmission medium at a wavelength that does not correspond to the maximum gain for the Raman-Stokes order shift, wherein the optical energy is converted with less efficiency than if the gratings were written at wavelengths that correspond to the maximum gain for the Raman-Stokes order shifts, wherein maximum reflection efficiency occurs at wavelengths that correspond to Raman-Stokes order shifts,wherein the gratings in the output region of said optical transmission medium are disposed in sequence according to center wavelength, with center wavelengths decreasing with increasing distance from the input region, andwherein the defined optical cavities convert optical energy of the input wavelength .lambda..sub.p to optical energy having the output wavelength .lambda..sub.n.