Abstract: A compression-tuned fiber Bragg grating based reconfigurable wavelength add/drop module has a compression force assembly and an all-glass Bragg grating compression unit having gratings spaced along an axis of compression. The compression force assembly responds to a control electronics signal containing information about a selected wavelength of a channel to be added to or dropped from an optical traffic signal, for providing a compression force applied along the axis of compression. The compression unit responds to the optical traffic signal and the compression force, for providing an all-glass Bragg grating compression unit optical signal having the selected wavelength of the channel to be added to or dropped from the optical traffic signal. The compression unit optical signal may include either the traffic with an added reflected channel(s), or a dropped reflected channel(s).

Abstract: A reconfigurable optical blocking filter deletes a desired optical channel(s) from an optical WDM input signal, and includes a spatial light modulator having a micro-mirror device with a two-dimensional array of micro-mirrors that tilt between first and second positions in a “digital” fashion in response to a control signal provided by a controller in accordance with a switching algorithm and an input command. A collimators, diffraction grating, and Fourier lens, collectively collimate, separate and focus the optical input channels onto the array of micro-mirrors. The optical channel is focused on the micro-mirrors onto a plurality of micro-mirrors of the micro-mirror device, which effectively pixelates the optical channels. To delete an input channel of the optical input signal, micro-mirrors associated with each desired input channel are tilted to reflect the desired input channel away from the return path.

Abstract: A chromatic dispersion compensation device selectively delays a respective portion of spectral sections of each respective optical channel of an optical WDM input signal to compensate each optical channel for dispersion compensation, and includes a spatial light modulator having a micromirror device with a two-dimensional array of micromirrors. The micromirrors tilt or flip between first and second positions in a “digital” fashion in response to a control signal provided by a controller in accordance with a switching algorithm and an input command. A collimator, diffraction gratings, and Fourier lens collectively collimate, disperse and focus the optical input channels onto the array of micromirrors. Each optical channel is focused onto micromirrors of the micromirror device, which effectively pixelates the optical channels.

Abstract: A temperature compensated optical device includes a compression-tuned glass element 10 having a Bragg grating 12 therein, a compensating material spacer 26 and an end cap 28 all held within an outer shell 30. The element 10, end cap 28 and shell 30 are made of a material having a low coefficient of thermal expansion (CTE), e.g., silica, quartz, etc. and the spacer 26 is made of a material having a higher CTE, e.g., metal, Pyrex®, ceramic, etc. The material and length L5 of the spacer 26 is selected to offset the upward grating wavelength shift due to temperature. As temperature rises, the spacer 26 expands faster than the silica structure causing a compressive strain to be exerted on the element 10, which shifts the wavelength of the grating 12 down to balance the intrinsic temperature induces wavelength shift up. As a result, the grating 12 wavelength is substantially unchanged over a wide temperature range.

Abstract: The present invention provides a method for annealing an optical waveguide, including an optical fiber or large-diameter waveguide structure, having along some length an induced refractive index difference that decays over time and so causes drift in the wavelength of reflected light when broadband light is inserted into the optical waveguide. The method uses an assumed decay formula for the induced refractive index difference indicating how the induced refractive index difference decays over time, the assumed decay formula having parameters that depend on temperature. The method includes the steps of: determining the (temperature dependent) parameters in the assumed decay formula for both an operating temperature and an annealing temperature, the annealing temperature being higher than the operating temperature, by fitting the observed decay over a measuring time at the two temperatures; and determining an anneal time at the annealing temperature based on a maximum allowed drift at the operating temperature.

Abstract: A compression-tuned Bragg grating-based laser 800 includes a pair of optical grating elements 802,804 wherein at least one of the grating elements is tunable by a compression device 812,814. The grating elements may include either an optical fiber 10 having at least one Bragg grating 12 impressed therein encased within and fused to at least a portion of a glass capillary tube 20 or a large diameter waveguide grating element 600 having a core and a wide cladding. The tunable grating element(s) 802,804 are axially compressed, which causes a shift in the reflection wavelength of the gratings 807,809 without buckling the element. The shape of the element may be other geometries (e.g., a “dogbone” shape) and/or more than one grating or pair of gratings may be used and more than one fiber 10 or core 612 may be used. A gain element, such as Erbium doped fiber, is optical disposed between the grating elements to provide the lasing cavity.

Abstract: A tunable optical filter filters is provided that has a pair of tunable Bragg grating units optically coupled to respective ports of a 4-port circulator for filtering a selected wavelength band or channel of light from a DWDM input light. Each grating unit includes an array of Bragg gratings written or embedded within a respective tunable optical element to provide a tunable optical filter that functions over a wide spectral range greater than the tunable range of each grating element. The reflection wavelengths of the array of gratings of each respective grating element is spaced at a predetermined spacing, such that when a pair of complementary gratings of the grating elements are aligned, the other complementary gratings are misaligned. Both of the optical elements may be tuned to selectively align each complementary grating over each corresponding spectral range.

Abstract: A tunable Raman laser and amplifier include a pair of tunable optical units optically connected by a length of optical fiber having an associated Raman gain. The tunable optical units tune respective optical waveguides, each of which includes an inner core disposed within an outer cladding. A plurality of Bragg gratings is written in each core of the waveguides. The reflection wavelengths of each Bragg grating of the input waveguide is the same as the reflection wavelength of a matched grating of the output waveguide, to thereby form a plurality of cascaded resonance cavities. Each resonance cavity has a reflecting wavelength equal to the center wavelength of successive Stokes orders associated with optical fiber. The Bragg gratings of each waveguide are written into a corresponding stepped region ground into the outer cladding of the waveguides. The tuning (e.g.

Abstract: An actuator mechanism for a tunable optical filter unit that filters a selected wavelength band of the input light from a DWDM input light. The input light comprises a plurality of wavelength bands or optical channels of light, each of which are centered at a respective channel wavelength. The actuator mechanism exerts a substantially linear force to strain or stress a tunable optical filter element to a desire reflection wavelength(s). A controller, in accordance with a control algorithm, provides a drive signal to the actuator mechanism in response to a command signal and a feedback signal indicative of the center wavelength of the desired optical channel(s) to be filtered. The actuator mechanism includes a drive mechanism that translates linearly a slide in response to the drive signal.

Abstract: A reconfigurable optical add/drop multiplexer (ROADM) selectively drops and/or adds desired optical channel(s) from and/or to an optical WDM input signal. The ROADM includes a spatial light modulator having a micro-mirror device with an array of micro-mirrors, and a light dispersion element. The micro-mirrors tilt between two positions in response to a control signal provided by a controller in accordance with a switching algorithm and input command. Collimators, diffraction gratings and Fourier lens collectively collimate, separate and focus the optical input channels and optical add channels onto the array of micro-mirrors. Each optical channel is focused on micro-mirrors of the micro-mirror device, which effectively pixelates the optical channels. To drop and/or add an optical channel to the optical input signal, mirrors associated with each desired optical channel are tilted away from a return path to the second position.

Abstract: A reconfigurable optical channel monitor selects and determines a parameter of desired optical channel(s) from and/or to an optical WDM input signal. The OCM includes a spatial light modulator having a micro-mirror device with a two-dimensional array of micro-mirrors that tilt between first and second positions in response to a control signal from a controller in accordance with a switching algorithm and an input command. A collimator, diffraction grating, and Fourier lens collectively converge the optical input channels onto the micro-mirrors array. The optical channel is focused onto a plurality of micro-mirrors. To select each input channel, a group of micro-mirrors associated with each desired input channel is tilted to reflect the desired input channel back along the return path to a photodetector and processing unit to determine a parameter of the selected input signal.

Abstract: A tunable optical device has a compression tuned optical structure and a displacement sensor. The compression tuned optical structure responds to an optical signal, and further responds to a displacement sensor signal, for providing a compression tuned optical structure signal containing information about a change in an optical characteristic of the compression tuned optical structure, and for also further providing an excitation caused by a change in a displacement of the compression tuned optical structure. The displacement sensor responds to the excitation, for providing a displacement sensor signal containing information about the change in the displacement of the compression tuned optical structure. The compression tuned optical structure may be in the form of a dogbone structure that is an all-glass compression unit having wider end portions separated by a narrower intermediate portion.

Abstract: A reconfigurable optical interleaver/deinterleaver device combines/separates a pair of optical input signals from and/or to an optical WDM input signal. The interleaver device includes a spatial light modulator having a micro-mirror device with a two-dimensional array of micro-mirrors that flip between first and second positions in a “digital” fashion in response to a control signal provided by a controller in accordance with a switching algorithm and an input command. A pair of collimators, diffraction gratings and Fourier lens collectively collimate, separate and focus the optical input channels and optical add channels onto the array of micro-mirrors. Each optical channel is focused on a plurality of micro-mirrors of the micro-mirror device, which effectively pixelates the optical channels.

Abstract: An optical cross-connect is provided that selectively switches at least one desired optical channel between a pair of optical WDM input signals. The cross-connect includes a spatial light modulator having a micro-mirror device with a two-dimensional array of micro-mirrors. The micro-mirrors tilt or flip between a first and second position in a “digital” fashion in response to a control signal provided by a controller in accordance with a switching algorithm and an input command. A pair of collimators diffraction gratings and Fourier lens collectively collimate, separate and focus the optical input channels and optical add channels onto the array of micro-mirrors. Each optical channel is focused on the micro-mirrors onto a plurality of micro-mirrors of the micro-mirror device, which effectively pixelates the optical channels. The optical channels have a cross-section (e.g.

Abstract: A smart node is provided for use in an optical communications network wherein the smart node comprising dynamically reconfigurable optical signal manipulation devices in combination with sensing devices and processors to provide real time closed and open loop control of various channels of the network.

Abstract: Prior to performing a centroid calculation on a waveform signal that is discretely sampled at a limited number of sample points, the last sample point (VN, AN) is eliminated if the magnitude of the amplitude at the first sample point (A1) is greater than the last sample point (AN), and the difference in magnitude between the first and last sample points (A1−AN) is greater than the difference in magnitude between the second to last sample point and the first sample point (AN−1−A1). The first sample point (V1, A1) is eliminated prior to the centroid calculation if the magnitude of the amplitude at the last sample point (AN) is greater than the first sample point (A1), and the difference in magnitude between the last and first sample points (AN−A1) is greater than the difference in magnitude between the second sample point and the last sample point (A2−AN).

Abstract: A method and corresponding apparatus for determining the centroid (Vc) of a waveform signal being sampled at a set of parameter values (Vi, i=1, . . . , n) yielding a corresponding set of sampled amplitudes (Ai, i=1, . . . , n), each parameter value and corresponding amplitude forming a sampled point (Vi, Ai), the method including the steps of: selecting an amplitude at which to create an interpolated point; interpolating a first parameter value corresponding to the amplitude selected in the step of selecting an amplitude; and performing a centroid calculation using only the sampled points with an amplitude greater than a predetermined threshold. The waveform is sometimes sampled in the presence of background noise, and the method sometimes also includes: estimating the background (Bi) for each value in the set of parameter values at which sampling is performed; and reducing the amplitude (Ai) of each sampled amplitude by the background (Bi) so estimated.

Abstract: A tube-encased fiber grating includes an optical fiber 10 having at least one Bragg grating 12 impressed therein which is embedded within a glass capillary tube 20. Light 14 is incident on the grating 12 and light 16 is reflected at a reflection wavelength &lgr;1. The shape of the tube 20 may be other geometries (e.g., a “dogbone” shape) and/or more than one concentric tube may be used or more than one grating or pair of gratings may be used. The fiber 10 may be doped at least between a pair of gratings 150,152, encased in the tube 20 to form a tube-encased compression-tuned fiber laser or the grating 12 or gratings 150,152 may be constructed as a tunable DFB fiber laser encased in the tube 20. Also, the tube 20 may have an inner region 22 which is tapered away from the fiber 10 to provide strain relief for the fiber 10, or the tube 20 may have tapered (or fluted) sections 27 which have an outer geometry that decreases down to the fiber 10 and provides added fiber pull strength.

Abstract: A method of applying a metal coating to optical element, such as an optical waveguide, comprising the steps of partially depleting stabilizers in an electroless metallic solution and immersing an optical waveguide in the electroless metallic solution to deposit the metal coating to the optical waveguide. The step of partially depleting may include creating an electroless metallic solution having a sodium hypophoshite concentration of about 25 grams per liter. The electroless metallic solution may comprise a Fidelity solution 4865A, a Fidelity solution 4865B and de-ionized water in a ratio of 1:1:18; and sodium hypophosphite crystals. Alternatively, the step of partially depleting may include placing a dummy load into the electroless metallic solution. The dummy load may be a rectangular block of metal, formed of a low carbon steel, and may have a threaded cylindrical passage therein.

Abstract: A method and device for tuning an optical device including an optical fiber having a core, a cladding and a Bragg grating imparted in the core to partially reflect an optical signal at a reflection wavelength characteristic of the spacing of the Bragg grating. The cladding has two variation regions located on opposite sides of the Bragg grating to allow attachment mechanisms to be disposed against the optical fiber. The attachment mechanisms are mounted to a frame so as to allow the spacing of the Bragg grating to be changed by an actuator which tunes the reflection wavelength. In particular, the variation region has a diameter different from the cladding diameter, and the attachment mechanism comprises a ferrule including a front portion having a profile substantially corresponding to diameter of the variation region and a butting mechanism butting the ferrule against the optical fiber.