Patent ID: 6445851
Filing Date: 2002-09-03
Classification: G02B

Abstract:
An optical waveguide having an interior grating with a periodicity for backreflecting a selected wavelength signal that is within a wavelength band including signals at other wavelengths, comprising:a tapered waveguide section having a narrow waist region of core and cladding including a doped photosensitive region, the waist region being less than 10 microns in diameter, the waist region including an index of refraction grating of a periodicity chosen for reflecting the selected wavelength, wherein the waist region has a substantially uniform diameter and the cross sectional area of the doped photosensitive region is in excess of 20% of the cross sectional area of the waist region, and wherein the diameter of the waist region is set such that higher order lossy mode reflections are shifted in wavelength below the band of the signals.