Abstract: A grating based optical de-interleaver useful over a wide wavelength range is presented. An echelle grating is used as dispersive element. The spectral response of the device is cyclic. The free spectral range of the grating is designed to separate wavelength channels to be de-interleaved. This device, being bi-directional will also operate as an interleaver.

Abstract: A waveguide optical monitor is disclosed. The device has an optical input port coupled through a switch to a plurality of input waveguides. A dispersive element disperses light within the input optical waveguides toward a plurality of output waveguides. There are a plurality of photodetectors each optically coupled to an output waveguide. The photodectors are for sensing an intensity of light within the waveguide with which it is optically coupled. An optical switch in optical communication with the optical input port and for switching light received at the optical input port to one of the plurality of input waveguides.

Abstract: In a digital optical switch, an input waveguide and two output waveguides form a Y-shaped splitter or switch. Electrodes are positioned on each output waveguide at the junction with the input waveguide. The electrodes extend as narrow strips across the waveguides. The inner edges of the electrodes are curved to form a smooth continuation profile to the signal paths to reduce losses.

Abstract: A homogeneous semiconductor waveguide structure having an undoped core layer and doped cladding layers on both sides of the core layer is proposed wherein the waveguide core is substantially thick providing polarization independence. Because of the cladding layers having low refractive index contrast with respect to the core and being on opposing sides resulting in a substantially symmetrical structure, the waveguide, can be made single-mode with low polarization sensitivity, thus improving characteristics for conducting light therein. Furthermore, the enlarged mode size increases coupling efficiency. Also, since the waveguide is grown from a single semiconductor composition lattice matched to the substrate, wafer uniformity and reproducibility are enhanced. The three layer structure reduces birefringence sufficiently that a yield enhancing etch stop layer can be added to the structure without substantially adverse effects.

Abstract: A grating based optical wavelength demultiplexer that can be used for multiple wavelength bands over a wide wavelength range is presented. The spectral response of the device is cyclic. The free spectral range of the grating is designed to be large enough to contain all the wavelength channels to be demultiplexed within a band but small compared to the overall wavelength window of the network application so that a multiplexed signal within any one of the wavelength bands within the application window can be demultiplexed by the same device. This device, being bidirectional will also operate as a multiplexer. By using such a cyclic design, an organization will not need to stock different parts for each band and thus significantly reduce the inventory cost.

Abstract: In a digital optical switch, an input waveguide and two output waveguides form a Y-shaped splitter or switch. Electrodes are positioned on each output waveguide at the junction with the input waveguide. The electrodes extend as narrow strips across the waveguides. The inner edges of the electrodes are curved to form a smooth continuation profile to the signal paths to reduce losses.

Abstract: A waveguide optical monitor is disclosed. The device has an optical input port coupled through a switch to a plurality of input waveguides. A dispersive element disperses light within the input optical waveguides toward a plurality of output waveguides. There are a plurality of photodetectors each optically coupled to an output waveguide. The photodectors are for sensing an intensity of light within the waveguide with which it is optically coupled. An optical switch in optical communication with the optical input port and for switching light received at the optical input port to one of the plurality of input waveguides.

Abstract: A variable optical attenuator is disclosed having a waveguide modification. Light coupling from an input waveguide to an output waveguide is electrically controllable through an electrically variable refractive index region, wherein attenuation of the device is dependent upon the applied voltage to the electrically variable refractive index region.

Abstract: A grating based optical wavelength demultiplexer that can be used for multiple wavelength bands over a wide wavelength range is presented. The spectral response of the device is cyclic. The free spectral range of the grating is designed to be large enough to contain all the wavelength channels to be demulitiplexed within a hand but small compared to the overall wavelength window of the network application so that a multiplexed signal within any one of the wavelength bands within the application window can be demultiplexed by the same device. This device, being bi-directional will also operate as a multiplexer. By using such a cyclic design, an organization will not need to stock different parts for each band and thus significantly reduce the inventory cost.

Abstract: A grating based optical de-interleaver useful over a wide wavelength range is presented. An echelle grating is used as dispersive element. The spectral response of the device is cyclic. The free spectral range of the grating is designed to separate wavelength channels to be de-interleaved. This device, being bi-directional will also operate as an interleaver.

Abstract: A dynamic gain equalizer using amplification instead of attenuation is disclosed. The device relies on integrated semiconductor optical amplifiers in line with a demultiplexer on a single integrated substrate for performing equalization of signals within each of a plurality of channels.

Abstract: A bidirectional multiplexer and demultiplexer based on a single waveguide grating is presented. In one embodiment of the invention, the device contains a multi/demultiplexer having an echelle grating disposed between a plurality of input channels and a plurality of output channel arrays. The input and output channels are assigned in a particular order, such that the multiplex and demultiplex functions have the same wavelength channels and such that the blaze angle of the grating facets are optimized simultaneously for both the multiplex and demultiplex function. Because the optical signals are multiplexed and demultiplexed by the same dispersive element, problems of mismatching performance introduced by using different optical components are obviated. The input/output waveguides of the dual-function device can be coupled to a single fiber array, thus reducing the packaging cost.

Abstract: An optical device for demultiplexing a plurality of interleaved sets of wavelength channels is described. The device supports at least two input ports in which each input port receives a plurality of optical channels corresponding to the normal output of an optical frequency interleaver. These signals are separated by the device in dependence of wavelength. This device, being bidirectional will also operate as a multiplexer.

Abstract: In a digital optical switch, an input waveguide and two output waveguides form a Y-shaped splitter or switch. Electrodes are positioned on each output waveguide at the junction with the input waveguide. The electrodes extend as narrow strips across the waveguides. The inner edges of the electrodes are curved to form a smooth continuation profile to the signal paths to reduce losses.

Abstract: A waveguide structure having a homogeneous core material and opposing cladding layers is proposed wherein the waveguide core is substantially thick providing polarization independence and wherein a coupling port of the waveguide core is characterized in that it has an expanded mode for better coupling to fibre. A method is presented for producing such an expanded core.

Abstract: A planar waveguide optical device whose wavelengths are stabilized by temperature, has an input channel, a series of output data channels, and a dispersive element, such as a diffraction grating or phase array, for directing component wavelengths of incoming light into the respective output data channels. A pair of monitor channels have a separation less than, and a width greater than, the data channels. A differential feedback arrangement controls the temperature of the demultiplexer according a differential signal received from the pair of monitor channels.

Abstract: A passband flattened waveguide grating device and a method of designing the same are disclosed wherein the resulting spectral response has a wide flat passband and steep transitions. The method involves adjusting the phases of grating elements forming the grating to achieve the desired spectral response. The phase variation between adjacent grating elements comprises of, in addition to a multiple of 2&pgr;, a slow-varying central phase variation and an oscillatory phase variation. The resulting spectral response of the waveguide device accounts for the effect of convolution of the field distribution profiles of the input port and of the output ports of the device.

Abstract: A device for compensating the temperature sensitivity normally associated with an integrated optical waveguide grating device has a temperature compensating slab waveguide region. This compensating region is provided within the slab waveguide region normally present in the grating device by modifying a sub-region of a predetermined shape and dimension to change its temperature coefficient of refractive index. This method and device can be applied to reflective and transmissive diffraction gratings and to phased array waveguide gratings.

Abstract: A device for compensating the birefringence normally associated with an integrated optical waveguide grating device has a polarization compensating slab waveguide region. This compensating region can be provided within the slab waveguide region normally present in the grating device by etching, doping, ion implanting a sub-region of a predetermined shape and dimension to change its birefringence. Alternatively, or in combination with changing the birefringence in this sub-region, electrodes can be provided for electro-optically changing the birefringence dynamically as required. This device can be applied to reflective and transmissive diffraction gratings and to phased array waveguide gratings.

Abstract: An active semiconductor device that performs in a substantially polarization independent manner. A quantum well waveguide is intermixed by intermixing atoms across an interface between well and barrier layers. The atoms include at least 2 groups wherein intermixing of one group is at a substantially greater rate than another group. Cations are interdiffused at a greater rate than said anions across interfaces between well and barrier layers. The intermixing must be sufficient to provide strain within layers of the waveguide and sufficient to at least partially degenerate light hole and heavy hole bands of the structure. Preferably intermixing is sufficient to completely degenerate light hole and heavy hold bands to essentially produce a device that is completely polarization independent.