Abstract:
A method is disclosed for polarization birefringence compensation in a photonic device with a slab waveguide having a core. A compensator region is formed in the slab waveguide to minimize the wavelength shift between light of different polarizations. A thin capping layer, typically of silicon nitride, having a higher refractive index than the core, is formed on the compensator region to increase the birefringence contrast between the compensator region and the planar waveguide.
Abstract:
An optical performance monitor for measuring the performance of optical networks has an echelle grating for demultiplexing an input beam into a plurality of wavelengths that are focused onto an array of divided output waveguides. Each divided output waveguide is positioned to receive a corresponding demultiplexed wavelength from the echelle grating or other waveguide multiplexer device. The divided output waveguides laterally separate the corresponding demultiplexed wavelength into a first and second portions. A detector array is positioned to receive the respective portions of the demultiplexed wavelengths and by comparing their relative intensity it is possible to detect any drift in the nominal wavelengths of the channels.
Abstract:
A method of measuring birefringence in an optical waveguide is described wherein light is propagated through the waveguide in both TE and TM modes. The birefringence of the waveguide is computed from the interference between scattered light originating from the respective TE and TM modes of propagation.
Abstract:
An optical performance monitor for measuring the performance of optical networks has an echelle grating for demultiplexing an input beam into a plurality of wavelengths that are focused onto an array of divided output waveguides. Each divided output waveguide is positioned to receive a corresponding demultiplexed wavelength from the echelle grating or other waveguide multiplexer device. The divided output waveguides laterally separate the corresponding demultiplexed wavelength into a first and second portions. A detector array is positioned to receive the respective portions of the demultiplexed wavelengths and by comparing their relative intensity it is possible to detect any drift in the nominal wavelengths of the channels.
Abstract:
An echelle grating includes is located on the edge of an integrated waveguide. The waveguide includes a buffer layer (7)and a core layer (6). The grating is etched through the core layer into the buffer layer. The grating is covered by a dielectric layer (8). The dielectric coating is covered by a metal layer (5). The dielectric layer inserted between the core layer and the metal reflecting layer reduces the polarization dependence of the grating.
Abstract:
An Echelle grating has alternate first (1a) and second (1b) sets of facets (1). The first set of facets (1a) is operative to reflect incident light (4) for diffraction and the second set of facets (1b) extends between adjacent facets of the first set (1a). Only the first set of facets (1a) is metallized to enhance reflection. The second set of facets (1b) is left unmetallized. This configuration reduces polarization dependent loss (PDL).