Abstract: A control system is designed to control an optical cross-connect having a switch core defined by first and second independently movable beam deflectors capable of selectively defining an optical path between a pair of ports of the optical cross-connect. An optical element having optical power is arranged in a propagation path of light beams between the first and second beam deflectors. The control system includes a pilot light source, an optical sensor associated with each beam deflector, and a feedback path. The a pilot light source inserts a pilot light into the switch core colinearly with live traffic. The optical sensor detects a predetermined geometric property of the pilot light emerging from the switch core. This predetermined geometric property is unambiguously associated with an angular position of the associated beam deflector. The feedback path actively controls a position of the associated beam deflector based on the detected geometric property.

Abstract: Described are various optical devices having at least two optical waveguides for inputting and outputting optical beams coupled thereto by a single collimating lens. Located proximate to the lens is a polarization dependent beam directing device that deflects orthogonally polarized optical beams in opposite directions by a first and second angle, respectively, when the beams are propagating in the same direction. The polarization dependent beam director compensates for an angle between a first beam input via a first of the two waveguides and a second beam input via a second of the two waveguides. The polarization dependent beam director also deflects a first beam propagating towards the waveguides in a first direction so that it is output via the first of the two waveguides and deflects a second beam propagating towards the waveguides in a second direction opposite the first so that it is output via the second of the two waveguides. Disclosed are three and four port interleavers and a four port circulator.

Abstract: Bi-directional wavelength interleaving optical isolators provide the ability to pass a first set of optical signals (e.g., ITU even channels) from a first port to a second port, while preventing a second set of optical signals from passing thereto. The bi-directional wavelength interleaving optical isolators also pass the second set of optical signals (e.g., ITU odd channels) from the second port to the first port, while preventing the first set of optical signals from passing thereto. Thus, the bi-directional wavelength interleaving optical isolator can provide bi-directional communications by passing a first set of signals in a first direction and a second set of signals in a second direction.

Abstract: In an effort to greatly decrease the insertion losses inherent in larger sized M×N optical switches, the present invention deals with minimizing the variation in the optical path lengths of optical beams passing through the switch. To accomplish this goal, the present invention relates to a segmented optical switch comprising four segments, two segments having input ports and two segments having output ports. The segments having output ports are separated from each other, and positioned on adjacent sides of the segments with input ports. Accordingly, the very short optical paths as well as the very long optical paths in the switch are eliminated, thereby minimizing the variation in the optical path lengths. Preferably, the switch is comprised of four identical segments, making manufacturing and supply costs less.

Abstract: A wavelength blocker including an input port for launching an input beam of light, first dispersing means for dispersing the input beam of light according to wavelength, an array of independently addressable elements for selectively blocking a portion of the dispersed beam of light, second dispersing means for receiving the passed dispersed beam of light and for producing a single multiplexed beam of light therefrom, and an output port for transmitting a modified output beam of light. The array of independently addressable elements are designed such that the wavelength blocker is capable of blocking a variable number of non-consecutive channels without significantly affecting the unblocked channels.

Abstract: A resonant optical cavity is disclosed that has a first partially reflective input end face and a second partially reflective end spaced a predetermined distance apart. The cavity is substantially angle insensitive to a beam of light launched into the cavity at a non-normal angle of incidence to the first input end face along a first line lying on a first plane orthogonal to the first input end face. The second end includes a retroreflector having at two or more partially reflective facts for redirecting light. An optical element having optical power such as a curved mirror or a lens for focusing light is disposed between the retroreflector and the other of the first and second ends. If the optical element having optical power is rotationally symmetrical the optical resonant cavity can be angle insensitive to all input angles. This device is particularly suited for use in the fabrication of an GT or MGT optical device.

Abstract: Optic switches manipulate an optical signal that has been expanded by a collimating lens. Switching is effected by introducing a prism between collimating lenses to redirect the optical signal to an alternative lens. The prism preferably has a cross-section defining a parallelogram, so that the optical signal is reflected twice within the prism to minimize cross-sectional distortion and avoid spectral effects. A circuit provides feedback on the actual position of the relay and prism for fault detection and diagnosis.

Abstract: A conventional interleaver, based on a stack of waveplates, relies on the orientation and the birefringence of the waveplates to differentiate the polarizations of one set of channels from another, so that the one set of channels can be separated from the other. The present invention relates to a virtual waveplate that is used to replace a birefringent waveplate. A virtual waveplate imposes a phase delay between the extraordinary ray and the ordinary ray by separating one from the other and differentiating the actual path lengths taken thereby, before recombining them. An interleaver constructed with the virtual waveplates of the present invention can be substantially a-thermal and potentially chromatic dispersion free.

Abstract: The present invention relates to a multi-stage non-blocking optical switch matrix having failure protection. The optical switch includes failure protection in the form of a capacity to provide an alternative route for any connection, including rearrangeable protection to provide alternative routes for multiple connections, as required, and to permit replacement of any failed submatrix module without service interruption. The present invention provides both internal and external protection from system failure in a multi-stage optical switch matrix by providing interconnected modules in a first external stage. The modules are interconnected by rerouting ports for redirecting signals from an input/output port on one external switch module to another external switch module. Protection is further provided through a center stage having a number of center stage switch modules, fully connected to the external modules, equal to twice the number of input/output ports and rerouting ports on an external module.

Abstract: An electrooptic waveplate for changing the state of polarization of light passing therethrough is disclosed. The waveplate provides a substantially constant birefringence when the principle birefringent axes of the electrooptic waveplate are rotated. The waveplate is an electro-optical material having two principle orthogonal birefringent axes that are rotable when suitable voltages are applied. Two related different voltages are applied along sequential or contiguous regions along the length L of the electo-optical waveplate for providing a controllable and varying electric field along the length L, such that retardance of the waveplate of the length L remains substantially constant while the birefringent axes of the elecrooptic waveplate are rotated by varying the voltages. The two different voltages have a phase relationship or a phase and magnitude relationship therebetween.

Abstract: An optical device comprises a dispersion element, a reflector, and an angle-to-offset (ATO) element. The angle-to-offset (ATO) element has optical power. The dispersion element is positioned in or near a focal plane of the ATO element and adapted to separate an input wavelength division multiplexed (WDM) light beam received from an input port of the optical device into two or more channel light beams. The reflector is positioned in or near a focal plane of the ATO element and arranged to receive the channel light beams from the dispersion element via the ATO element. The reflector is designed to reflect at least one of the channel light beams toward a respective output port of the optical device. With this arrangement, the dispersion element, reflector and ATO element cooperate to optically demultiplex the input WDM light beam.

Abstract: A system for wavelength locking i.e. for maintaining a frequency of an optical signal to within predetermined limits has means for splitting part of the controlled optical signal into at least three sub-beams of which one is a reference beam and two others are provided to an optical element having a periodic output response and to a filter having a monotonic output response. The three detected outputs are analyzed and processed to determine accurately the wavelength of the optical signal and to produce a correcting signal if it is not within the predetermined limits.

Abstract: The invention relates to a pigtailing method, i.e., the invention provides an optical device comprising a substrate on which are integrated a layered optical waveguide component (3) and optical fiber ends (13). The optical fiber ends are positioned in grooves (10). The method involves providing a substrate (7) comprising grooves (10), notably V-shaped grooves, with a separately made optical waveguide component (3). The component (3) is made on separate flat substrate (1), and released by virtue of a releasable layer (2) present on the flat substrate (1). An advantageous releasable layer is made of a water-soluble salt. The invention also pertains to flexible waveguide sheets such (3) as can be used in the above method or, if provided with waveguide channels (12), as a flexible waveguide component themselves.

Abstract: Automated manufacturing in the fiber optics industry has introduced a series of new problems due to the small size of the parts being assembled and the precise optical alignments required. However, processes requiring the manual assembly of parts using glue are slowly being replaced by automated processes involving the laser welding of metallically encased optical parts. Unfortunately, almost every step in the process causes a small degree of misalignment, which may cause the device to fall below transmission standards. The present invention provides a method of assembling an optical device which includes special steps that involve re-aligning the elements in the optical device after other steps in the method have caused a misalignment. In particular, the method of the present invention includes testing the alignment of the optical elements at several stages throughout the assembly process, and applying addition asymmetric welds to the finished product to improve the transmission results.

Abstract: A method of controlling a response function of a pixelated dynamic gain controller involving structuring the problem as a set of linear equations that are used to efficiently and accurately determine an initial set of pixel settings and further can be iterated to determine optimum pixel settings for a desired response function. In particular, the gain controller is comprised of an array of individually controllable pixels such as an array of liquid crystals. Adjusting drive conditions to each pixel controls the relative transmission of a narrow band of wavelengths through each pixel. The target response function is achieved by structuring the control conditions as a set of linear equations with which it is possible to accurately determine an initial set of pixel settings. The settings can be iterated to determine an optimum setting for a desired response function or change in response function. Additionally, compensating pixels at the edges of the array are used to compensate for edge effects.

Abstract: The present invention relates to an optical coupling between an end of an optical fibre and an end of a lens, which provides a reliable joint with a determined spacing and angular orientation. The optical coupling permits movement of the end of the optical fibre relative to the lens in at least two alignment directions. Advantageously, the present invention permits movement of the end of the optical fibre relative to the end of the lens in a direction perpendicular to the optical axis of the lens, before the optical coupling is secured. The optical fibre within an optical fibre tube/ferrule and the lens are secured within separate sleeves and the sleeves bonded together. The end of the optical fibre and the end of the lens are optically aligned before being secured in place relative to each other. Alternatively, the invention provides similar advantages in coupling two lenses to one another via separate sleeves they are contained within.

Abstract: The present invention relates to a micro-electromechanical optical attenuator and a method of operating the same. In prior art attenuators, the attenuation obtained from a deflection angle does not change uniformly over a range of interest. In addition, over a range of interest the required voltage to obtain a desired deflection changes as a nonlinear function. The cause of the poor control of prior art attenuators can be viewed graphically by examining the attenuation as a function of deflection, and the angle of deflection as a function of voltage. These functions combine to produce a very unstable voltage to attenuation response function. The present invention has found that by operating an electrostatic drive of a reflective optical attenuator in order to attain a low loss state with the mirror in a fully deflected position, the drive voltage can be reduced to increase attenuation in a very stable nearly linear attenuation vs. drive voltage response. The non-linearity of the attenuation vs.

Abstract: An optical waveguide device has a hybrid core and a cladding. A first waveguide having a glass core is coupled to a polymer waveguide disposed adjacent and parallel to the first waveguide such that the respective cores are contiguous in a coupling region. The polymer is a thermo-optically active polymer. A heater is provided over the coupling region and the refractive index of the polymer is varied by applying heat to the region. By application of sufficient heat, the refractive index of the polymer can be changed to approach the refractive index of the cladding whereby the device acts as a simple glass waveguide. In the absence of heat, the device acts as a MMI coupler.

Abstract: A method and system is disclosed of characterizing an optical amplifier for operation with a required tilt or curvature within predetermined limits. As the temperature of the erbium-doped optical amplifier is varied while a test signal is launched into the amplifier accompanied by a pump signal the output spectrum is compared with a desired spectrum. At different temperatures different measures of tilt or curvature are present at the output port of the amplifier in the presence of an input signal at the input port. Feedback related to the measure of tilt or curvature of at least one of the plurality of different temperatures is provided in the form of a feedback signal or an information signal.

Abstract: A hermetically sealed package for an electro-optical device has a two-part casing with a fiber feedthrough. The feedthrough defines a gap and is assembled using fastening means, typically bolts or screws, that are placed such that the walls of the feedthrough are prestressed before a molten solder is injected into the feedthrough to seal the casing. The material of the bolts has a greater coefficient of thermal expansion (CTE) than the CTE of the casing, whereby the mismatching between the CTE of the casing and the solder is at least partly compensated.