Abstract: The invention provides a micro-electro-mechanical-system (MEMS) mirror device, comprising: a mirror having a 2-dimensional rotational articulated hinge at a first end, and having a 1-dimensional rotational articulated hinge at a second end opposite the first end; a movable cantilever connected to the mirror through the 1-dimensional rotational articulated hinge; a support structure connected to the mirror through the 2-dimensional rotational articulated hinge and connected to the movable cantilever; whereby movement of said movable cantilever causes rotation of the mirror in a first axis of rotation, and the mirror is also rotatable about a second torsional axis of rotation perpendicular to said first axis of rotation.

Abstract: The invention provides an optical switch having a pair of opposed optical arrays, each optical array including a fixed mirror and a plurality of independently tiltable mirrors, at least one input port for launching a beam of light into the optical switch, said input port being disposed within a respective optical array, at least two output ports for selectively receiving a beam of light from an optical path between the at least one input port and a selected one of the at least two output ports, said at least two output ports being disposed within a respective opposed optical array, and an ATO element having optical power disposed between the pair of opposed optical arrays. The pair of opposed optical arrays is disposed in respective focal planes of the ATO element. Preferably, the ATO element has a focal length equal to a Rayleigh range of a beam of light incident thereon.

Abstract: Interleavers, based on a Michelson interferometer with a Gires-Tournois (GT) etalon in each arm, are becoming popular in the filtering of light in the fiber optics telecommunications industry. As the channel spacing becomes closer together, e.g. 50 GHz or 25 GHz, dispersion compensation becomes an important factor in the choice and design of a system. The present invention solves the problem of increased chromatic dispersion by utilizing multi-cavity Gires-Tournois (MCGT) etalons, wherein the dispersion from one MCGT is used to compensate or cancel the dispersion from the other MCGT. In an optimum design for a dual cavity GT etalon, the dispersion profile of the first MCGT will have a similar amplitude and frequency as the dispersion profile of the second MCGT, only shifted by half the period so that the positive slopes of one profile are aligned with the negative slopes of the other profile.

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: 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 interferometer useful in the interleaving and de-interleaving of optical wavelength channels. Typically the invention comprises a beamsplitter and two resonators, e.g. GT etalons or ring resonators. The beamsplitter splits an input beam of light into a first sub-beam directed to follow a first path and a second sub-beam directed to follow a second path. The first resonator has a first effective cavity length and receives the first sub-beam. The second resonator has a second effective cavity length and receives the second sub-beam. The first path and the second path have an effective optical path difference approximately equal to one-half the first effective cavity length. In one embodiment, the front plates of the GT etalons each have a different reflectivity, and are selected to provide a desired spectral response.

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: 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: 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 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: 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: 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: 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: 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: 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: The invention provides a cylindrical polarization diversity circuit for narrowing the numerical aperture of an incoming beam of light in a direction perpendicular to the dispersion direction and without affecting the numerical aperture of the incoming beam of light in the direction of dispersion. A cylindrical lens is employed to provide an output beam having an elliptical cross-section. The output beam is collimated in one direction and diverging in a direction perpendicular thereto. A birefringent element having its walk-off direction oriented such that it coincides with the collimated beam direction separates the output beam into two orthogonally polarized sub-beams having an elliptical cross-section. The sub-beams are substantially non-overlapping. Advantageously, a halfwave plate is provided so as to make the polarization states of both sub-beams substantially parallel.

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: An optical device for rerouting and modifying an optical signal that is capable of operating as a dynamic gain equalizer (DGE) and/or a configurable optical add/drop multiplexer (COADM) is disclosed. The optical design includes a front-end unit for providing a collimated beam of light, an element having optical power for providing collimating/focusing effects, a diffraction element for providing spatial dispersion, and modifying means which in a preferred embodiment includes one of a MEMS array and a liquid crystal array for reflecting and modifying at least a portion of a beam of light. The modifying means functions as an attenuator when the optical device operates as a DGE and as a switching array when the optical device operates as a COADM.