Abstract: An optical switch using a Michelson interferometer and differential onset of optical nonlinearity. Modulation of optical signals can occur at speeds that exceed that of electronic devices.

Abstract: A method and device for re-writing data on a holographic storage device is disclosed. First and second electro-optic modulators may phase shift the reference and data beams used to store data on the photorefractive crystal. When the reference beam is shifted 180° out of phase with respect to the data beam, the photorefractive crystal is erased.

Abstract: A directly modulated spatial light modulator (DM-SLM) may be formed using a semiconductor optical amplifier. The directly modulated spatial light modulator may also be formed with a vertical cavity surface emitting laser having an output side; and an anti-reflection coating located on the output side.

Abstract: A method and system for bulk erasing in a holographic storage system is disclosed. The method may involve illuminating the entire volume storage region of a photorefractive crystal with a laser to achieve bulk erasure, or may involve selective erasure of a portion of a single written page. For bulk erasure of the entire photorefractive crystal the use of a separate laser or an incoherent light source is used.

Abstract: A system and method for providing eye-safety protection during operation of a lumped optical amplifier. The method is based on monitoring of continuous out-of-band Raman amplified spontaneous scattering (ASS) created by the amplified signal in an optical communication network span coupled to an output port of the lumped optical amplifier. The system includes at least one gain stage for providing an amplified signal introduced into the span, a monitoring unit for performing the continuous Raman ASS monitoring, and a control unit operative to detect and analyze in real-time changes in the ASS power, and upon determination that such changes indicate an open span, to reduce the power of the amplified signal or shut down the gain stage.

Abstract: Efficient wavelength calibration in a WDM optical amplifier that includes an optical channel monitor (OCM) is obtained by introducing a notch into the amplified spontaneous emission (ASE) noise spectrum of the amplifier outside a WDM transmission band, and having the OCM detect the notch and use the notch as a reference to calibrate the wavelength measurement. The notch is introduced into the ASE noise spectrum using a notch filter, which is preferably incorporated in a gain flattening filter (GFF).

Abstract: An embodiment of the invention comprises an optical element capable of motion in at least one degree of freedom wherein the motion in at least one degree of freedom is enabled by serpentine hinges configured to enable the optical element to move in at least one degree of freedom. The embodiment further includes driving elements configured to deflect the optical element in said at least one degree of freedom to controllably induce deflection in the optical element and a damping element to reduce magnitude of resonances. Another embodiment includes a MEMS optical apparatus comprising an optical element capable of motion in two degrees of freedom. The two degrees of freedom are enabled by two pairs of serpentine hinges. A first pair of serpentine hinges is configured to enable the optical element to move in one degree of freedom and a second pair of serpentine hinges is configured to enable the optical element to move in a second degree of freedom.

Abstract: Described are MEMS mirror arrays monolithically integrated with CMOS control electronics. The MEMS arrays include polysilicon or polysilicon-germanium components that are mechanically superior to metals used in other MEMS applications, but that require process temperatures not compatible with conventional CMOS technologies. CMOS circuits used with the polysilicon or polysilicon-germanium MEMS structures use interconnect materials that can withstand the high temperatures used during MEMS fabrication. These interconnect materials include doped polysilicon, polycides, and tungsten metal.

Abstract: Described are methods for fabricating Micro-Electro-Mechanical Systems (MEMS) actuators with hidden combs and hinges. The ability to hide the combs renders the actuators useful in digital micro-mirror devices. Comb actuators provide increased torque, which facilitates the use of stiffer, less fragile hinge structures. Also important, comb actuators do not require mechanical stops to define stable states, and thus avoid problems associated with physical contact. The actuators are infinitely variable through a range of angles.

Abstract: Described are various optical, opto-electrical and electrical components and subsystems. Some embodiments include input and output waveguides supporting opposing facets separated by a gap. The degree to which the opposing facets are aligned with respect to one another controls the light intensity in the output waveguide. An active closed-loop control mechanism dynamically controls the extent of waveguide alignment to maintain a desired output intensity. In other embodiments, the path between opposing facets can be selectively blocked by a micro blade. Still other embodiments combine switching with optical power equalization for ease of integration.

Abstract: Described are MEMS mirror arrays monolithically integrated with CMOS control electronics. The MEMS arrays include polysilicon or polysilicon-germanium components that are mechanically superior to metals used in other MEMS applications, but that require process temperatures not compatible with conventional CMOS technologies. CMOS circuits used with the polysilicon or polysilicon-germanium MEMS structures use interconnect materials that can withstand the high temperatures used during MEMS fabrication. These interconnect materials include doped polysilicon, polycides, and tungsten metal.

Abstract: An embodiment of the invention comprises an optical element capable of motion in at least one degree of freedom wherein the motion in at least one degree of freedom is enabled by serpentine hinges configured to enable the optical element to move in at least one degree of freedom. The embodiment further includes driving elements configured to deflect the optical element in said at least one degree of freedom to controllably induce deflection in the optical element and a damping element to reduce magnitude of resonances. Another embodiment includes a MEMS optical apparatus comprising an optical element capable of motion in two degrees of freedom. The two degrees of freedom are enabled by two pairs of serpentine hinges. A first pair of serpentine hinges is configured to enable the optical element to move in one degree of freedom and a second pair of serpentine hinges is configured to enable the optical element to move in a second degree of freedom.

Abstract: Fiber, lens and sensor arrays and their precision alignment for optical devices with free space light propagation is disclosed Fabrication methods of arrays and their assembly are also proposed. In one implementation, a device includes a fiber alignment module holding fibers in parallel to form a fiber array. The fiber alignment module includes first and second alignment plates, and a spacer plate engaged between the first and the second alignment plates. Each alignment plate includes an array of through holes to respectively hold the fibers. A lens array can be engaged to the fiber alignment module to align lenses to their corresponding fibers. Passive alignment features may be formed at interfacing surfaces of different layers to assist the alignment. Applications of these integrated fiber, lens and sensor arrays to optical cross connect switches and reconfigurable add drop multiplexers are also disclosed.

Abstract: A Micro-Electro-Mechanical Systems (MEMS) actuator employs electrostatic comb electrodes to position optical elements along multiple axes. In one embodiment, an actuator assembly includes an actuator support, typically a silicon wafer, supporting a fixed comb with a plurality of teeth. A frame flexibly connected to the actuator support includes a complementary set of movable comb electrodes, the teeth of which are arranged interdigitally with the teeth of the fixed combs. The frame can be tilted with respect to the actuator support along a first fulcrum axis by applying a potential difference between the fixed and movable combs. Each actuator assembly also includes an actuated member, a mirror mount in one embodiment, flexibly connected to the frame. The actuated member and the frame include electrical isolated, interdigitated, combs. The actuated member can be moved relative to the frame along a second fulcrum axis by applying a potential between these interdigitated combs.

Abstract: Described are Micro-Electro-Mechanical Systems (MEMS) actuators with hidden combs and hinges. The ability to hide the combs renders the actuators useful in digital micro-mirror devices. Comb actuators provide increased torque, which facilitates the use of stiffer, less fragile hinge structures. Also important, comb actuators do not require mechanical stops to define stable states, and thus avoid problems associated with physical contact. The actuators are infinitely variable through a range of angles.

Abstract: Described is a photolithography “pattern transfer” process for forming Micro-Electro-Mechanical Systems (MEMS) structures. A first material layer is patterned so that raised portions of the layer define features of a MEMS structure to be formed. The resulting pattern is then “transferred” to the surface of a second material layer by etching the top surface of the first material layer, including the raised portions and the valleys defined between the raised portions, until the second layer is exposed between the raised portions.

Abstract: A method of defect detection and repair of micro-electro-mechanical systems (MEMS) devices comprising the steps of (A) detecting at least one defect in the MEMS device, wherein each defect is an object that prevents the MEMS device from functioning substantially properly; (B) performing repair of each detected defect; (C) checking whether the MEMS device is functioning substantially properly after each detected defect is repaired; and (D) if the MEMS device is not functioning substantially properly after each detected defect is repaired, repeating steps (A-C).

Abstract: Described is a photolithography “deep-well lithography” process for forming Micro-Electro-Mechanical Systems (MEMS) structures. The process differs from conventional lithography in that the surface being patterned is not the uppermost surface, but is instead the bottom of a “well” defined beneath the uppermost surface. The focal plane of the photolithography equipment is offset from the uppermost surface as appropriate to account for the depth of the well in which the pattern is to be formed. The bottom of the well is then patterned to produce a desired structure.

Abstract: Variable optical attenuators that use a blade in a gap between two fibers to control the optical attenuation without having coupling optics in the gap, where the blade has at least one blade surface at an angle with respect to an end facet of one fiber.

Abstract: Controllable optical switches in response to feedback signals from optical position sensors that measure switch orientations. The optical position sensors may include local sensors that monitor and measure orientations of individual switches and global sensors that monitor and measure overall alignment of signal beams. Such switches may be used to form non-blocking switching arrays.