Abstract: Broadband optical switches based on adiabatic couplers having a pair of asymmetric waveguides with variable curvature sections include in a 2×2 configuration based on a Mach-Zehnder interferometer two such adiabatic couplers, and in a 1×2 or 2×1 configuration an adiabatic coupler and an Y-splitter. Each adiabatic coupler includes two waveguide branches of different but constant widths having curved sections with varying radii, separated over a coupling length by a changing spacing therebetween and blending in an asymmetric intersection area, and two symmetric branches. In the 2×2 switch, the two adiabatic couplers face each other with their respective symmetric branches, and are connected by the two identical arms along a main propagation axis in a mirror image. The utilization of the variable curvature adiabatic couplers in silica MZI switches on a silicon substrate provides switches with an exceptional broadband range (1.2-1.

Abstract: Ultra fast, compact wavelength-selective 2×2 optical switches based on polarization splitters and preferably electro-optical polarization converters, and switch matrices based on such switches. The switches and switch matrices are preferably implemented on electro-optical substrates using planar light-wave circuit technology. Switch designs include switches comprised of two polarization splitters and two polarization converters, and a switch comprised of one polarization splitter and two polarization converters. In a preferred embodiment, a switch comprises a TE-barring polarization splitter, a TM-barring polarization splitter, and two electro-optical wavelength-selective polarization converters connected in parallel between the TE- and TM-barring polarization splitters, and is implemented on an electro-optical substrate such as InP, GaAs, LiNbO3 or LiTaO3 using planar lightwave circuit technology.

Abstract: A method and system of operating a variable optical attenuator to provide a required total attenuation in a planar lightwave circuit. The method comprises providing a first Mach-Zehnder interferometer having a first and a second arm carrying signals in an arbitrary polarization state, providing a second Mach-Zehnder interferometer having a third and a fourth arm carrying signals in an arbitrary polarization state, the second Mach-Zehnder interferometer concatenated in tandem with the first Mach-Zehnder interferometer, and cooperatively operating the concatenated first and second Mach-Zehnder interferometers to obtain the required total attenuation and an effectively nil polarization dependent loss.

Abstract: A method for operating a planar lightwave circuit at a constant power consumption, comprises providing a matrix of integrated active elements, heating independently each active element with a separate heating power, and cooperatively operating the heating powers of the active elements to keep a sum of the operating heating powers constant in time independently on the dynamic operation of the element. The active element has two connecting configurations and is operative to have a phase change in a light beam passing through each of the connecting configurations, both connecting configurations being constantly heated. The active element is operable in both analog and digital modes with a constant power consumption.

Abstract: A system for switching optical energy from a plurality of input waveguides to a plurality of output waveguides, while balancing power in the output waveguides, and a method for its use. The system is based on an optical switch matrix that includes, for each input waveguide and for each output waveguide, one or more attenuators that divert an adjustable portion of the optical energy, that enters via that input waveguide, to that output waveguide. Preferably, each input waveguide is coupled to each output waveguide via a pair of 2×2 mach-Zehnder interferometers, a first of which has an idle input port and a second of which has an idle output port. The system also includes a feedback mechanism that taps fixed portions of the power in either the input waveguides or the output waveguides, and adjusts the attenuators accordingly.

Abstract: A safety shutter module adapted to fit onto a standard fiber-optics connector which terminates a transmission line conveying light signals of high intensity to be received by an adapter when it is coupled to the connector. When decoupled, these light signals leak from the front end of the connector and are radiated therefrom. This radiation is hazardous to the eyes of individuals exposed thereto. The module is composed of a cap that fits onto the connector and is provided with a visor that projects beyond the front end, the visor having a hinged shutter plate that depends therefrom to block the radiation. But when the adapter is plugged into the connector, it then acts to swing the shutter plate upwardly against the visor to admit the adapter and unblock the connector.

Abstract: A system for switching optical energy from a plurality of input waveguides to a plurality of output waveguides, while balancing power in the output waveguides, and a method for its use. The system is based on an optical switch matrix that includes, for each input waveguide and for each output waveguide, one or more attenuators that divert an adjustable portion of the optical energy, that enters via that input waveguide, to that output waveguide. Preferably, each input waveguide is coupled to each output waveguide via a pair of 2×2 Mach-Zehnder interferometers, a first of which has an idle input port and a second of which has an idle output port. The system also includes a feedback mechanism that taps fixed portions of the power in either the input waveguides or the output waveguides, and adjusts the attenuators accordingly.

Abstract: An optical switch matrix connects N input waveguides to M output waveguides via M rows of switch sets. Each row of switch sets includes a first switch set that has one input port and two output ports, N−2 intermediate switch sets that have two input ports and two output ports, and a last switch set that has two input ports and one or two output ports. One output port of each first or intermediate switch set is optically coupled to an input port of a succeeding switch set in the same row, and the other output port is optically coupled to an input port of a respective switch set in a cyclically succeeding row, by intermediate waveguides that do not cross each other. The only exceptions are the intermediate waveguides that connect the last row to the first row. These intermediate waveguides may cross other waveguides.

Abstract: An optical switch array in which at least three input waveguides are coupled to at least three output waveguides. Each of the output waveguides is coupled in the same order to each of the input waveguides by a switching element such as a 1×2 switch, via an intermediate waveguide and a combining mechanism that includes a coupling element such as a y-junction combiner. For compactness, the switching elements that couple to the same output waveguide are mutually displaced along the input waveguides. Optionally, each of the input waveguides is coupled to an auxiliary waveguide, which in turn is coupled to further output waveguides.

Abstract: An optical switch network, for connecting P switch input waveguides to Q switch output waveguides. The switch input waveguides enter a branching subnetwork consisting of a plurality of branching cascades. In each branching cascade, an array of 1×2 splitters connects the input waveguides of the cascade to the output waveguides of the cascade, and the output waveguides of the cascade cross within the cascade so that output waveguides that connect to the same switch input waveguide emerge from the cascade P output waveguides apart. The output waveguides of the branching subnetwork connect directly to 2×1 combiners of a combining subnetwork that connects the output waveguides of the branching subnetwork to the Q switch output waveguides. The network architecture is reversible, by exchanging the roles of the input and output waveguides and the roles of the splitters and the combiners.

Abstract: An optical switch array in which a plurality of input waveguides is coupled to a plurality of output waveguides. All but one of the output waveguides is coupled to each of the input waveguides by a switching element such as a 1×2 switch. A combining mechanism couples all the input waveguides to each of the output waveguides. In one preferred embodiment, one of the input waveguides continues directly into the output waveguide that is not coupled to input waveguides by switching elements, and each combining mechanism includes, for each of the other input waveguides, a coupling element such as a y-junction combiner. The switching elements are connected to the corresponding combining mechanisms by intermediate waveguides. Intermediate waveguides intersect input waveguides as required to allow the array to be fabricated as a planar integrated device.