Abstract: Integration of laser sources into optoelectronic integrated circuits requires that the laser do not operate using two cleaved end facets. Unfortunately, replacing of one of the end facets results by either a dry etched mirror or by a corner reflectors results in undesirable performance of the laser source since a gain coefficient for the laser source is lower than that for a dual cleaved end facet laser source. A modified waveguide is thus proposed which serves to reduce the undesirable effects found when a corner reflector is used by providing an improved waveguide region between the cleaved end facet and the corner reflector that facilitates excitation of a single optical mode within a laser cavity formed between the corner reflector and the cleaved end facet.

Abstract: Integration of laser sources into optoelectronic integrated circuits requires that the laser do not operate using two cleaved end facets. Unfortunately, replacing of one of the end facets results by either a dry etched mirror or by a corner reflectors results in undesirable performance of the laser source since a gain coefficient for the laser source is lower than that for a dual cleaved end facet laser source. A modified waveguide is thus proposed which serves to reduce the undesirable effects found when a corner reflector is used by providing an improved waveguide region between the cleaved end facet and the corner reflector that facilitates excitation of a single optical mode within a laser cavity formed between the corner reflector and the cleaved end facet.

Abstract: The invention discloses a method for monolithic integration of active devices within passive semiconductor waveguides and the application of this method for use in InP-based planar wavelength division multiplexing components of optical communication systems. The epitaxial device is grown in a single run and comprises a number of layers, such that the lower part of the structure acts as a single mode passive waveguide while the upper part of the structure contains a planar PIN diode. The PIN structure is present only in the active waveguide portion and absent in all the passive waveguide portions. The active and passive waveguide portions have substantially similar guiding properties with the exception of a mode tail above a top surface of the passive waveguide portion within the active waveguide portion.

Abstract: Integration of laser sources into optoelectronic integrated circuits requires that the laser do not operate using two cleaved end facets. Unfortunately, replacing of one of the end facets results by either a dry etched mirror or by a corner reflectors results in undesirable performance of the laser source since a gain coefficient for the laser source is lower than that for a dual cleaved end facet laser source. A modified waveguide is thus proposed which serves to reduce the undesirable effects found when a corner reflector is used by providing an improved waveguide region between the cleaved end facet and the corner reflector that facilitates excitation of a single optical mode within a laser cavity formed between the corner reflector and the cleaved end facet.

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 design for a polarization independent ridge waveguide structure is shown. The inventive waveguide structure features discontinuous trenches formed on either side of the waveguide in which the waveguide has a first polarization characteristic absent the trenches and a second polarization characteristic when the trenches are present. The length of the trenches and the distance between the trenches are chosen to provide a desired amount of attenuation to each of the TE and TM modes. Additionally, this method is used to cause a predetermined polarization in order to compensate for the polarization of another optical component.

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: 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: An optical wavelength multiplexing device for use in an optical networking environment is presented. The device features optically dispersive elements combined with an array of reflectors that permit both realization of flat-top filter characteristics together with noise reduction, and in some embodiments wavelength routing, blocking or add-drop functionality. Additionally, the design of the device is easily modified to dissipate light having a wavelength that does not correspond to any predetermined wavelength channel.

Abstract: A design for controlling optical modes in a closely spaced weakly confined waveguide array is described wherein the crosstalk between individual waveguides is suppressed by segmented deep etched trenches. One exemplary embodiment of the invention incorporates a shallow etched ridge waveguide array at the output coupler of a semiconductor optical demultiplexer. In this situation, all higher order modes and supermodes are filtered by a sequence of deep etched trenches located between the shallow etched ridge waveguides. The trenches have a minimal effect on the single fundamental mode of the individual shallow etched waveguides because the trenches are located far enough from the ridge waveguides where an evanescent tail of the fundamental mode approaches a minimal power level. The trenches affect and suppress all other modes including higher order leaky modes and array supermodes leaving the single fundamental mode propagating in the arrayed waveguides.

Abstract: An optical echelle grating for use with a switching fabric to provide different wavelength switching assemblies such as an optical cross connect. The single grating receives a plurality of multiplexed input optical signals and provides optical signals corresponding to the individual wavelength channels to a switching fabric. The switching fabric routes the signals corresponding to the wavelength channels appropriately and the signals then propagate to the grating once more and are wavelength multiplexed.

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 technique for hermetically sealing an optical component in a metal package is described. Variations of the technique are described in which optical communication between the optical component and the outside environment is achieved with a ribbon fibre.

Abstract: The present invention relates to a semiconductor optical amplifier system integrated within a semiconductor waveguide structure. The semiconductor optical amplifier system comprises a first semiconductor optical amplifier having a first spectral response and a second semiconductor optical amplifier having a second other spectral response. The second semiconductor optical amplifier is coupled to the first semiconductor optical amplifier for optically receiving an amplified optical signal from the first semiconductor optical amplifier.

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 accordance with the present invention a multifrequency Raman pump laser cavity is disclosed comprising of an angularly dispersive element optically coupled to a shared waveguide terminated in a partially reflecting facet; a plurality of laser diode sources for radiating at frequencies for Raman amplification each for providing laser light at a different frequency and spatially oriented in relation to the angular dispersive element such that light emitted from each source is reflected from the angularly dispersive element toward a same output port; at least two partially reflecting coating for forming a laser cavity therebetween wherein the grating is within the laser cavity or defines a boundary thereto.

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: 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.