Abstract: Optical communication systems include a central station that encodes data transmitted to multiplexing (mux) stations or user stations. The central station also decodes data received from the mux stations or user stations. Encoding and decoding are performed using codes, such as composite codes, that designate sources and destinations for data. The mux stations, user stations, and the central station have address encoders and decoders that use, for example, fiber Bragg gratings to encode or decode optical signals according to a code such as a composite code derived by combining codes from one or more sets of codes. A passive optical network comprises one or more levels of mux stations that use such address decoders and encoders to receive, decode, and encode data for transmission toward a central station or a user station.

Abstract: An optical phased array transmitter/receiver includes a plurality of waveguides each including an optical fiber and a light source coupled to the fibers in the waveguides. At least one grating is coupled to the fiber of each waveguide and at least one phase shifter coupled to the fiber of at least one waveguide. The phase shifter controls a phase profile of light passing through the fiber to control a profile of a laser beam reflected at the grating. The gratings reflect light passing through the fibers outside of the optical coder to form a laser beam shaped and directed by the grating and phase shifters. Further, a detector is coupled to the waveguides that is enabled to receive light reflected off the gratings.

Abstract: In some embodiments, an optical engine for a display system utilizes a wire grid clean-up polarizer for polarization cleanup. In some embodiments, a liquid crystal component, separate from the spatial light modulator, is utilized for gamma control. Other embodiments are disclosed and claimed.

Abstract: According to embodiments of the present invention, a retarder for a liquid crystal on silicon microdisplay cell may include a twisted nematic cell sandwiched between index of refraction matching layers, isotropic material (for example, glass) disposed on the top and bottom index matching layers and antireflective material disposed on the top and bottom isotropic layers. In one embodiment, the retarder includes a fast axis oriented substantially ninety degrees out of phase relative to a fast axis of the residual retardance of the liquid crystal on silicon microdisplay cell.

Abstract: Optical circuits having a flat wavelength response are disclosed. A disclosed apparatus includes a first optical coupler, first and second optical waveguides optically coupled to the first optical coupler and a second optical coupler optically coupled to the first and second optical waveguides. The first optical coupler couples input light into a first portion and a second portion. The first and second optical waveguides receive the first and second portions of input light from the first optical coupler, respectively the second optical coupler couples the first portion of input light from the first optical waveguide and the second portion of input light from the second optical waveguide. The second optical waveguide may effect a fixed phase difference of one-half wavelength relative to the input light. The first and second optical couplers may have first and second wavelength dependences, respectively, where the second wavelength dependence is opposite the first wavelength dependence.

Abstract: Multiple Bragg gratings are fabricated in a single planar lightwave circuit platform. The gratings have nominally identical grating spacing but different center wavelengths, which are produced using controlled photolithographic processes and/or controlled doping to control the effective refractive index of the gratings. The gratings may be spaced closer together than the height of the UV light pattern used to write the gratings.

Abstract: A system for fabricating Bragg gratings includes an optical waveguide (e.g., an optical fiber, a planar waveguide), an interference pattern generator (e.g., a transmission phase grating such as a phase mask or a diffraction grating), first motion equipment (e.g. a nanostage), a pulsed light source (e.g. an excimer laser), and second motion equipment (e.g. a stepper motor). A method for fabricating Bragg gratings using this system includes providing relative motion between the optical waveguide and the interference pattern using the nanostage, providing relative motion in discrete increments between the pulsed light source and the assemblage comprising the optical waveguide, nanostage, and interference pattern generator using the stepper motor, and successively exposing the optical waveguide to the pulsed light through the interference pattern generator when the optical waveguide and interference pattern are effectively stationary relative to the pulsed light.

Abstract: A mounting platform provides support and packaging for one or more fiber Bragg gratings and electronic circuitry (e.g., heaters, coolers, piezoelectric strain providers, temperature and strain sensors, feedback circuitry, control loops), which may be printed on or on the mounting platform, embedded in the mounting platform, or may be an “off-board” chip solution (e.g., the electronic circuitry may be attached to the mounting platform, but not formed on or defined on the mounting platform). The fiber Bragg gratings are held in close proximity to the electronic circuitry, which applies local and global temperature and/or strain variations to the fiber Bragg gratings to, for example, stabilize and/or tune spectral properties of the fiber Bragg gratings so that spatial variations in the fiber Bragg gratings that result from processing and manufacturing fluctuations and tolerances can be compensated for.

Abstract: A structure (i.e. a segmented grating) which applies a designated complex-valued spectral filtering function to the input optical field and emits a filtered version of the input field in an output direction and a method for making such a structure. The segmented gratings fabricated in accordance with the present invention consist of a series of spatially distinct subgratings arrayed end to end. Each subgrating possesses a periodic array of diffraction structures (lines or more general elements).

Abstract: A structure (i.e. a segmented grating) which applies a designated complex-valued spectral filtering function to the input optical field and emits a filtered version of the input field in an output direction and a method for making such a structure. The segmented gratings fabricated in accordance with the present invention consist of a series of spatially distinct subgratings arrayed end to end. Each subgrating possesses a periodic array of diffraction structures (lines or more general elements).

Abstract: A structure (i.e. a segmented grating) which applies a designated complex-valued spectral filtering function to the input optical field and emits a filtered version of the input field in an output direction and a method for making such a structure. The segmented gratings fabricated in accordance with the present invention consist of a series of spatially distinct subgratings arrayed end to end. Each subgrating possesses a periodic array of diffraction structures (lines or more general elements).

Abstract: A variable-reflective tunable optical filter includes an interferometer adapted to control the powers of added or dropped signals and an optical waveguide grating to select the wavelength channels of the added or dropped signals. The waveguide grating is tunable to filter a dropped signal from an input data stream and filter an added signal into an output data stream. While a reflection band of the waveguide grating is being adjusted to tune a wavelength channel, the phase of at least one leg of the interferometer may be adjusted to direct signals of any wavelength channel selected by said waveguide from the input data stream to the output data stream, thereby providing hitless optical add-drop multiplexing.

Abstract: A mounting platform provides support and packaging for one or more fiber Bragg gratings and electronic circuitry (e.g., heaters, coolers, piezoelectric strain providers, temperature and strain sensors, feedback circuitry, control loops), which may be printed on or on the mounting platform, embedded in the mounting platform, or may be an “off-board” chip solution (e.g., the electronic circuitry may be attached to the mounting platform, but not formed on or defined on the mounting platform). The fiber Bragg gratings are held in close proximity to the electronic circuitry, which applies local and global temperature and/or strain variations to the fiber Bragg gratings to, for example, stabilize and/or tune spectral properties of the fiber Bragg gratings so that spatial variations in the fiber Bragg gratings that result from processing and manufacturing fluctuations and tolerances can be compensated for.

Abstract: A Bragg grating may be written at an arbitrary wavelength without extensive recalibration or reconfiguration of the writing equipment in some embodiments. A pair of writing beams may be used to expose a waveguide. The crossing angles of the writing beams may be adjusted. In one embodiment, circular wedges in each writing beam may be rotated about their axes to alter the crossing angle. In another embodiment, acousto-optic Bragg cells may be utilized to change the writing angle of the writing beams.

Abstract: A fiber Bragg grating may be written at an arbitrary wavelength without extensive recalibration or reconfiguration of the writing equipment in some embodiments. A pair of writing beams may be used to expose the fiber. The crossing angles of the writing beams may be adjusted.

Abstract: Communication systems and methods are disclosed that route, detect, and decode encoded optical signals at network nodes based on channel codes assigned to the network nodes. In an example communication system, a network hub includes a channel selector that encodes an optical signal with a channel code assigned to one or more network nodes. The channel selector is configured to encode based on a channel selection signal provided to the channel selector and can include one or more fiber Bragg coders. Code-switched communication systems can include one or more nodes configured in ring, tree, or bus architectures.

Abstract: In accordance with some embodiments of the present invention, while a Bragg grating is being written in a substrate, measurements may be taken to allow changes to be made in the writing process to reduce errors that may occur in the written grating. In one embodiment, multiple scans of the writing beam can be used. After a scan, measurements of the characteristics of the grating being written can be taken and corrections may be implemented on subsequent scans.

Abstract: Multiple Bragg gratings are fabricated in a single planar lightwave circuit platform. The gratings have nominally identical grating spacing but different center wavelengths, which are produced using controlled photolithographic processes and/or controlled doping to control the effective refractive index of the gratings. The gratings may be spaced closer together than the height of the UV light pattern used to write the gratings.

Abstract: Multiple Bragg gratings are fabricated in a single planar lightwave circuit platform. The gratings have nominally identical grating spacing but different center wavelengths, which are produced using controlled photolithographic processes and/or controlled doping to control the effective refractive index of the gratings. The gratings may be spaced closer together than the height of the UV light pattern used to write the gratings.

Abstract: The coupling properties of an optical device having at least two inputs and two outputs may be more accurately measured by simultaneously measuring the optical transmission through all outputs for light coupled to each input to the device. An optical switch may be used to selectively couple the light to each of the device inputs. This removes the need to remove the light source from one input and to reconnect it to another input. By proper processing of the measured optical transmission corresponding to each input, an accurate and precise value for the transfer function, including polarization properties, of the device may be obtained independent of the insertion losses in the system.