Seagate Technology Incorporated

Terastor Corporation

Capella Photonics, Inc.

Other

Sperry Rand Corporation

Nortel Networks Corporation

Prysm, Inc.

Brian Tremaine

Roger A Hajjar

Joseph Eugene Davis

Alan Claude Burroughs

Amit Jain

Guolin Ma

Brian T Bonn

Gordon R Knight

Warren Dalziel

James N Krause

David Blankenbeckler

John Al-Samarrie

Litko R Chan

Vlad Joseph Novotny

John F Heanue

Armand P Neukermans

Yung-Chieh Hsieh

Rajiv R Ramaswami

Mark H Garrett

Andrew M Rose

Bernard W Bell

Marc R Schuman

Charles E Mendenhall

Raymond G Gauthier

Michael J Darling

Hossein Moghadam

Chris Butler

Michael Darling

A laser-based display device includes a plurality of ultraviolet lasers configured to excite a phosphor-containing display screen in order to produce visible light. The laser-based display device also includes a reference laser used for calibration operations. A control system within the laser-based display device causes the reference laser beam to scan across one or more calibration features, and adjusts optical components of the laser-based display device, including activation timing of the ultraviolet lasers, based on feedback patterns generated by the calibration features, to compensate for drift effects. The calibration features may be disposed off-screen or on-screen.

Optical component calibration system for laser-based display device

Methods and apparatus for dither control of a micromirror using a servo control loop in an optical switching apparatus, an optical switching apparatus and optical network are disclosed. A servo control loop may use dither tone having two or more frequency components to dither an output driver that controls the position of a micromirror in an optical switch. The two components may be demodulated from an optical signal deflected by the micromirror. The optical signal may be fed into two band-pass filters. Each band-pass filter may have a pass band centered on a different one of the two frequency components. The envelope detector may compare the envelopes of the band-pass filter outputs. If the envelopes differ by more than a set threshold the output of the envelope detector may be forced to zero. Otherwise, the output of the envelope detector may be the sum of the two band-pass filter outputs.

Exogenous tone dither rejection in optical switching

Methods for adjusting dither amplitude for MEMS mirrors in optical switches and optical switches employing such a method are disclosed. A dither amplitude of one or more MEMS mirrors may be adjusted in an optical switch having an input port, and an array of one or more MEMS mirrors that can be selectively optically coupled to one or more of N&#x2267;3 optical input/output (I/O) ports. The MEMS mirrors are aligned mirrors to achieve nominal peak coupling at each of the N collimators. Digital-to-analog (DAC) settings for positioning mirrors in an open control loop as a function of the selected collimator are stored to a non-volatile memory. The DAC settings are used to determine a dither amplitude DITHER(x) for one of the MEMS mirrors positioned to couple optical signals to an output port at a position x. The optical switch apparatus may comprise N&#x2267;3 optical input/output (I/O) ports, an array of one or more MEMS mirrors that can selectively reflect one or more spectral channels to one or more of the N ports, and a servo-control assembly in communication with said one or more of the MEMS mirrors. The servo control assembly includes memory containing digital-to-analog converter (DAC) settings for positioning each mirror in an open control loop as a function of a port position x. The servo control assembly is programmed to adjust dither amplitude of one or more of the MEMS mirrors using the stored DAC settings.

Method of automatic adjustment of dither amplitude of MEMS mirror arrays

Effects of diffraction of a spectral beam from an edge of the micromirrors are reduced in order to optimize the passband in a wavelength selective switch. The effects of diffraction on the pass band may be reduced by using rotation of the micromirror about both the attenuation axis and the switching axis to achieve the desired level of attenuation. Peak coupling can be attained by dithering the micromirror about a dither axis that is tangent to a contour of constant attenuation using simultaneous rotation about the switching and attenuation axes. A power level of a spectral channel may be attenuated by rotating the channel micromirror with respect to an effective attenuation axis that is non-orthogonal to the dither axis through a combination of rotations about the switching axis and the attenuation axis.

Reduction of MEMS mirror edge diffraction in a wavelength selective switch using servo-based rotation about multiple non-orthogonal axes

Effects of diffraction of a spectral beam from an edge of the micromirrors are reduced in order to optimize the passband in a wavelength selective switch. The effects of diffraction on the pass band may be reduced by using rotation of the micromirror about both the attenuation axis and the switching axis to achieve the desired level of attenuation. Peak coupling can be attained by dithering the micromirror about an axis tangent to a contour of constant attenuation using simultaneous rotation about the switching and attenuation axes.

Reduction of MEMS mirror edge diffraction in a wavelength selective switch using servo-based multi-axes rotation

A wavelength selective switch architecture for ROADMs for switching the spectral channels of a multi-channel, multi-wavelength optical signal between input and output ports employs a biaxial MEMS port mirror array for optimal coupling efficiency and ITU grid alignment, an anamorphic beam expander for expanding input optical signals to create an elongated beam profile, a diffraction grating for spatially separating the spectral channels, an anamorphic focusing lens system, an array of biaxial elongated channel MEMS micromirrors, a built-in Optical Channel Monitor, and an electronic feedback control system. The bi-axial channel micromirrors are rotatable about one axis to switch spectral channels between ports, and are rotatable about an orthogonal axis to vary the coupling of the spectral channel to an output port and control attenuation of the spectral signal for complete blocking or for a predetermined power level. The architecture affords hitless switching, near notchless operation, ITU channel alignment, high passband, stability over a broad temperature range, and minimum insertion loss through the optimal optical coupling efficiency enabled by the feedback control system.

Optimized reconfigurable optical add-drop multiplexer architecture with MEMS-based attenuation or power management

Described is a method for controlling the angular position of a mirror. The method includes sensing the angular position of the mirror, generating a first linear control signal in response to the angular position and generating a first non-linear control signal to position the mirror. The method can also include generating a second linear control signal in response to the angular position and generating a second non-linear control signal to position the mirror. Generation of the linear control signal is based on conventional linear systems techniques. The method can be applied to mirror arrays in which the generation of the non-linear control signal is adapted for mirror performance variations.

Non-linear method for micro-mirror control

One aspect is a method for controllably attenuating the beam of light () coupled between incoming and outgoing optical fibers () by misaligning minor surfaces () included of an optical switching module (). Misalignment of the mirror surfaces (and) causes only a portion of the beam of light () propagating along the incoming optical fiber (), which is less than when the light beam deflectors' mirror surfaces () are precisely aligned, to propagate along the outgoing optical fiber (). Thus, the optical switching module () controllably attenuates the beam of light () coupled between the incoming and the outgoing optical fibers (). Another aspect is a variable-optical-attenuator ('VOA') () that includes an optically reflective membrane () upon which the beam of light () impinges. Application of an electrostatic field between an adjacent electrode () and the membrane () deforms the membrane () thereby attenuating an impinging beam of light ().

Variable attenuation of free-space light beams

A system and method for canceling disturbance in a MEMS device. The systemincludes a MEMS device, which may include a substrateand a plurality of individually movable MEMS elements-through-N, and a control assembly. The optical systemmay be utilized in and/or form a portion of any optical apparatus employing an array of MEMS devices. The control assemblyuses feed-forward control signals to cancel disturbance in the MEMS device, and more particularly, to cancel disturbance in the non-switched or static mirrors of the MEMS devicecaused by switched or moving mirrors.

System and method for canceling disturbance MEMS devices

Structures of storage media for optical storage systems, especially for systems in the near-field configuration to couple radiation between the optical head and the media at least in part by evanescent fields.

Disk mastering based on near-field optical systems

Magneto-optical storage media designed for optical storage systems such as disk drives with optical flying heads. Dielectric layers are designed and implemented to maximize optical coupling between the flying optical head and the media and to reduce variations of signals with flight height of the flying optical head.

Storage media for optical storage systems

An optical position detector which has adjacent detector cells connected to each other in a zig-zag pattern offers a wider dynamic range than a detector with a vertical separation line during transition between a read laser power and a write laser power. This allows use of a fast response bi-cell in place of a slower position sensing device (PSD). The optical position detector has detector cells coupled to each other in a zig-zag pattern. Each detector cell produces a signal when a light beam is focused onto the cell to indicate a location of the light beam relative to the cell.

Zig-zag-patterned position sensor system

An optical disk drive having a thermal control mechanism on the optical head to control the spacing between the optical head and the surface of the storage medium.

Mechanism for controlling spacing between optical head and storage medium in optical storage systems

Optical storage systems based on air-bearing-suspended optical heads in a near-field configuration. Such a system comprises an optical head for reading and writing data and a head positioning system, an optics module including beam relay optics and signal detectors, and a medium holding and loading module to hold an optical medium. An electronic control system is also provided to control the system operation. The optical head includes a near-field lens with a high index of refraction and in a near-field configuration in which the near-field lens has a numerical aperture greater than unity when the spacing between an exit facet of the optical head and a recording layer in the optical medium is a fraction of one wavelength of optical beam.

Optical storage systems with flying optical heads for near-field recording and reading

In a disc drive, a position error signal (PES) can be generated that is insensitive to the read element's magnetic and physical geometry and micro-track profile, and that has a spatial domain periodic frequency that corresponds to a frequency region of the micro-track profile that facilitates a high magnitude response. The servo pattern for generating this PES includes a first servo burst pair (A,B) and a second servo burst pair (C,D) of servo burst members, each pair written as normal and quadrature channels.

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San Jose, CA, United States of America

Brian Tremaine