Abstract: A multimode laser beam depolarization and combining architecture integrates a combiner for polarized multimode light beams with a multimode beam depolarizer, that produces a composite depolarized output beam optimized for application to a Raman optical amplifier. A high-order depolarizing 45° waveplate is used to effectively depolarize multimode laser beams produced by a Fabry-Perot (FP) laser. The high-order 45° waveplate has a length that achieves multi mode dispersion-dependent depolarization of the beam over its travel path through the crystal, and may comprise a birefringent material such as YVO4 having a large difference between its extraordinary and ordinary indices of refraction.

Abstract: The invention relates to replaceable modules for use in optical fiber distribution racks. The modules according to the present invention are mounted in the distribution rack at a slight angle, which enables a simple and effective latching mechanism to connect and disconnect the module therefrom using one hand. Moreover, a preferred embodiment of the present invention minimizes the required size of the module by positioning the input ports at an angle to the remainder of the module body, which has the added benefit of directing the attached cables away from the latching mechanism providing enfettered access thereto. The optical fiber distribution rack according to the present invention includes a sliding lower tray with a sliding upper frame member, whereby full access to both the tray and the frame member are provided.

Abstract: The invention provides polarization state changer and a phase shifter for shifting a phase of an optical signal including a waveguide having a waveguiding region for guiding the optical signal therethrough, a substrate for supporting said waveguide, and means for inducing stress on the waveguiding region for shifting the phase of the optical signal. The stress is induced by MEMS means. The MEMS means are monolithically formed on the substrate and can be actuated by electrostatical force, mechanical force, or tiltable flaps.

Abstract: An optical beam path directing system has a field-flattening optically transmissive wedge installed in spatially dispersed beam paths upstream of the planar surface of a micro electro-mechanical switch (MEMS) or liquid crystal array. The parameters of the field-flattening wedge and its location in the diffracted beam paths are defined such that the wedge effectively rotates a ‘best fit’ planar surface approximation of the curvilinear focal plane of a concave reflector into coplanar coincidence with the optical signal-receiving surface of the MEMS. As a result, loss variation is essentially flat and minimized across the optical signal transmission band.

Abstract: Optical waveplates made of polyethylene naphthalate (PEN) exhibit good optical properties comparable to or exceeding the respective properties of prior art waveplates made of polyimides (PI). PEN waveplates are a technically and commercially reasonable alternative to PI waveplates.

Abstract: The filtering of optical signals, and in particular the interleaving/de-interleaving of optical signals is becoming a necessary step in Dense-Wavelength Division Multiplexing (D-WDM), because of a requirement for smaller channel spacing due to higher levels of traffic. Finite Impulse Response (FIR) filters, including lattice and birefringent waveplate versions, are a particular type of optical filter used for interleavering/de-interleavering optical channels, which can be defined by their transfer function H(f). To ensure dispersion free filtering, the present invention provides a cascaded optical filter, comprising two optical filters, wherein the transfer function of the second filter is the complex conjugate of the first filter, i.e. H2(f)=H1*(f), or the complex conjugate of the first filter H1*(f) multiplied by the transfer function of a dispersion free optical filter G(f).

Abstract: This invention relates to elements such as birefringent crystals, which are used to separate a non-collimated input beam into two orthogonally polarized sub-beams or to combine two orthogonally polarized beams into a single beam. The optical device lessens or obviates the optical path length difference encountered in prior art devices and provides a polarization beam splitter/combiner that has substantially same optical path lengths for two split or combined beams propagating therethrough. Alternatively, the device is designed to provide a selected path length difference to compensate for polarization mode dispersion in other optical devices.

Abstract: An optical cross-connect having an input port for launching a beam of light into the optical cross-connect, at least two output ports, each output port for selectively receiving a beam of light, a dispersive element for dispersing the beam of light into separate wavelength channels, and a switch core for independently switching at least one individual wavelength channel between ports. The switch core includes a cylindrical ATO element, two cylindrical relay lenses, and two opposing deflector arrays. Conveniently, the deflector arrays are either liquid crystal phase arrays or reflective MEMS arrays.

Abstract: A fiber optic wavelength switch that includes a front-end unit having optical ports for receiving and transmitting optical signals; a wavelength dispersion element (e.g., diffraction grating, prism, etc.) for defining a dispersion plane; a light redirecting element (e.g., spherical reflector) associated with the wavelength dispersion element; and an actuation array (e.g., MEMS) operative with the light redirecting element for tilting an optical signal substantially perpendicular to the dispersion plane defined by the wavelength dispersion element. The wavelength switch can be implemented as a one input/output port and several add/drop ports type device, which can add/drop wavelengths from/to the in/out port. The front-end unit having a fiber array coupled to a micro-lens array with optical signals from the micro-lens being directed by a further lens.

Abstract: The present invention relates to an arrayed waveguide grating having a reflective input that permits variable coupling to adjust the center wavelength. The present invention has found that by providing an arrayed waveguide grating having one or more precisely positioned input waveguides coupled through a reflective lens assembly, for providing a lateral offset to a signal propagating from the input waveguide to the planar waveguide, and for focusing a reflected input signal at a selected input point of the input planar waveguide, alignment and tuning of an input and assembly can be improved and simplified. Advantageously, variable coupling parameters can be incorporated into the reflective coupling including input position, waveguide taper and planar waveguide length increment to provide relatively simple tuning in an integrated device. Compensation for polarization effects and thermal effects can also be provided in the reflective coupling.

Abstract: The present invention relates to bi-directional circulators based on interleaver technology, e.g. birefringent crystal interleaver technology, that enables signals containing even number ITU channels to travel in one direction through the device, while signals containing odd number ITU channels travel in the opposite direction. Open and closed three and four port devices are disclosed, as well as several useful implementations of the three port device in combination with other optical components, which result in hybrid uni-directional and bi-directional devices.

Abstract: A method and device is disclosed for dispersion compensation of an optical signal. By providing two filters having a sloped dispersion and opposite in sign over a wavelength band wherein one filter is tunable, a controllable amount of dispersion can be introduced to offset or compensate dispersion. Preferably one of the filters is a tunable periodic device in the form of a multi-cavity GT etalon. In a preferred embodiment of the filters can be designed to provide various controllable but different constant amounts of dispersion.

Abstract: In order to calibrate an apparatus for measuring the polarization dependent loss of an optical device under test, a set of nominal polarization states of incident light are generated with a polarization generator. The incident light is then passed through a dot-product conserving polarization rotator at a first setting. A transmission characteristic is measured through a standard optical component with a known polarization dependent loss value for each polarization state. This step is repeated for a number of different settings of the polarization rotator. A polarization dependent loss value is calculated for the standard optical component based on the measured transmission characteristics at each polarization rotator setting. The calculated polarization dependent loss values are then processed to generate an aggregate error value.

Abstract: The invention provides a hermetic fiber-optic seal, such as in an optical fiber ferrule or feedthrough, having an optical fiber, a glass solder for encasing at least a portion of the optical fiber, a first glass sleeve for encasing at least a first portion of the glass solder, a second glass sleeve for encasing at least a second portion of the glass solder, and an outer sleeve for encasing at least a portion of the first glass sleeve and the second glass sleeve. A gap filled with glass solder may be provided between the first glass sleeve and the second glass sleeve. The hermetic fiber-optic seal is made by an extrusion process.

Abstract: A micro-optical delay element for a time-division multiplexing scheme is disclosed wherein two light beams are provided to a beam splitter/combiner (BS/C) in the absence of optical fibre. At least one beam exiting a modulator is collimated and reaches the (BS/C) unguided as a substantially collimated beam.

Abstract: An important consideration in making a fiber optic device (e.g., comprising fiber in a polished tube at a certain angle and GRIN lens) is to limit sense, maintain and/or measure the gap-width between these two polished surfaces before they are either fused or glued for optimum performance. In automating the configuration, the gap is sensed, apart from optimizing in the transverse plane to minimize the loss. In the present application, a limit sensing method and system is provided to improve the effectiveness in automated manufacturing systems, by exploiting the electromechanical properties of induced EMF (Electro-Magnetic Force) by an electrical coil in presence of a magnet at mechanical resonance. Once it is known when two optical surfaces to be glued are said to have zero gap (i.e., contact between the surfaces), the present system provides an annunciation from limit-sensing electronics.

Abstract: A high capacity cross-connect in which a 3D switch core includes express paths that facilitate cascading of cross-connect blocks. A light beam propagates from an input waveguide 18 to a first MEMS mirror, which deflects the light beam to either an express optical path or a switching optical path. In the express optical path, the light beam propagates from the first MEMS mirror to a predetermined output waveguide, which is determined by the design of the switch core. In the switching optical path, the light beam propagates from the first MEMS mirror to a second MEMS mirror, which deflects the light beam to a selected one of a set of two or more output waveguides associated with the second MEMS mirror.

Abstract: A chassis for fiber optics communication equipment, having a housing with first and second opposing sides, and a back panel cooperating with the housing to provide fore-and-aft slots for cassettes containing optical communication equipment. A remote user interface module for making connections to other items of equipment, and a local user interface module for display of conditions in the cassettes, are situated at opposite sides of the housing, and are both connected to the base by docking stations which allow these modules to be interchanged in position so that either of the first or second sides of the housing may become the front of the chassis; i.e. may be adjacent the local user interface module. This allows the chassis to be reversible so that the cassettes can be removed either from the front or from the rear of the chassis while the local user interface module remains at the front of the chassis.

Abstract: An optical coupler and method of making an optical filter is disclosed wherein a compound lens having two separate movable lenses are disposed between input/output ports and a filter element, such as a dichroic filter element. The filter is tuned during assembly by varying the gap between the movable lenses. Once it is established that optimum coupling is achieved and a desired wavelength response is achieved, the two lenses are fixed in place.

Abstract: A drive towards automation, particularly in the fiber optics industry, has necessitated the use of materials and methods better suited for use by machines. The present invention takes advantage of the magnetic properties of these materials to create a strong magnetic bond between separate elements while they are being connected. Two independently controllable chucks are used to align the elements in accordance with design requirements. After proper alignment, the elements are magnetically attracted together and then permanently fixed using any one of a variety of standards methods, such as welding. In the embodiment of the invention used specifically in the fiber optics industry, the alignment process includes measuring the light transmitted or reflected by the two elements.