Patent ID: 6169830
Filing Date: 2001-01-02
Classification: G02B

Abstract:
The method of providing a wavelength selective optical coupler having a narrow bandwidth drop wavelength and high grating strength comprising the steps of: elongating a portion of one optical fiber pair each having a core and cladding to a narrow waist region in which the fibers are longitudinally merged and the core is vestigial; tapering optical fiber transitions to and from the waist region adiabatically to a dimension such that the optical modes of original fibers evolve adiabatically into orthogonal modes within the waist region;modifying the polarization dependence of the propagation constants of the orthogonal modes to establish substantial polarization independence of the drop wavelength in the operation of the coupler; photosensitizing the waist region; writing an apodized reflection grating having a periodicity adapted for the drop wavelength in the waist region while maintaining the photosensitization.