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).

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 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).

Abstract: A method is desribed for controlling the pass band of an optical device wherein a phase mask is introduced to modify the shaped of an image produced by the photonic device.

Abstract: The method consists of creating a compensating region within the slab waveguide region, with effective TE and TM mode refractive indices of the compensating region higher than those of the original slab waveguide. Such change in refractive indices is achieved by deposition of an over-layer on the compensating region.

Abstract: Disclosed is an optical double pass equalizer for equalizing a wavelength division multiplexed (WDM) signal. The equalizer comprises a multiplexer/demultiplexer and multiple variable optical attenuators (VOAs) integrated on a single monolithic chip. The WDM signal is demultiplexed into individual wavelength channels by the multiplexer/demultiplexer and each wavelength channel is equalized by a corresponding VOA. The equalized wavelength channels are then multiplexed into an equalized WDM signal by the multiplexer/demultiplexer. This provides several advantages, including a reduction in required assembly and assembly cost, as well as an improved dynamic range in attenuation level or alternatively a reduction in power consumption for a fix attenuation level compared to a single pass VOA unit.

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: 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 porous semiconductor is created by electrochemical etching. Selected regions of a semiconductor are first treated to reduce the threshold potential at which pore formation occurs, and then an electrochemical etch is carried out on the semicnoductor at a potential at least equal to the reduced threshold potential for the selected regions and less than the threshold potential for untreated regions. The selective treatment preferably involves implantation with the same ions as the semiconductor, i.e. Si ions for silicon. The treatment results in the formation of highly defined etch patterns or patterns of porous material depending on the process conditions.

Abstract: A porous semiconductor is created by electrochemical etching. Selected regions of a semiconductor are first treated to reduce the threshold potential at which pore formation occurs, and then an electrochemical etch is carried out on the semiconductor at a potential at least equal to the reduced threshold potential for the selected regions and less than the threshold potential for untreated regions. The selective treatment preferably involves implantation with the same ions as the semiconductor, i.e. Si ions for silicon. The treatment results in the formation of highly defined etch patterns or patterns of porous material depending on the process conditions.