At&t Bell Laboratories

Lucent Technologies Inc.

At+t Corp.

American Telephone & Telegraph Co., At&t Bell Laboratories

Other

Bell Telephone Laboratories

Agere Systems Guardian Corp.

American Telephone and Telegraph, Co.

Charles H Henry

Rudolf F Kazarinov

Yuan P Li

Henry H Yaffe

Edward J Laskowski

Leonard G Cohen

Michele A Milbrodt

Yosi Shani

Nils A Olsson

Renen Adar

Kenneth J Orlowsky

Greg E Blonder

Herman M Presby

Thomas Andrew Strasser

Christi Kay Madsen

Ralph A Logan

Ronald Edward Scotti

Rodney C Kistler

Corrado Pietro Dragone

Yiu-Huen Wong

Rodney C Alferness

Raymond Wolfe

Gadi Lenz

Daryl Inniss

Raymond A Cirelli

Roland A Levy

Yan Wang

Raymond Dingle

Weyl-Kuo Wang

Cecilia Y Mak

Morton I Schwartz

Aasmund S Sudbo

Mark E Kuznetsov

Glenn E Kohnke

Carl E Soccolich

Rudolf Feodor Kazarinov

Thomas Patrick Aherne

The invention is an apparatus including a semiconductor laser device emitting light at least at a certain wavelength, and at least two reflectors external to the laser device and positioned to reflect the light to stabilize the wavelength.

Wavelength stabilized laser modules

The present invention teaches a novel technique for reducing the temperature-related spectrum shifts in optical devices, particularly waveguide grating routers (WGR). In general, the present invention modifies a portion of the length of at least one waveguide within an optical device in a manner that stabilizes the wavelength spectrum passing therethough even when exposed to temperature variations. More specifically, by knowing how the refractive index of a certain material changes with temperature variations as compared to that of common waveguide materials, such a silica, one may employ the teachings of the present invention to precisely modify the nature of the optical path through which a signal travels to fully compensate for any temperature-related wavelength spectrum shift. In other words, be able to produce an optical device with a plurality of waveguides each of which is appropriately modified so that any optical signal passing therethrough has the same wavelength at any two given temperatures.

Method and apparatus for reducing temperature-related spectrum shifts in

In accordance with the invention, an optical multiplexer includes at least one reconfigurable add-drop unit that can add-drop one channel out of a large set by switching the light path through one of a set of fixed add-drop filters. Reconfiguration is done by switching from the add-drop filter path to a bypass path, changing to a different add-drop filter and then switching back. The phase delay of the bypass path is adjusted to maintain nearly maximum transmission during switching. The selection among add-drop filters is done by sliding an integrated optic chip with the set of add-drop filters between input and output waveguides. The reconfigurable add-drop multiplexer unit is latchable, passive between reconfigurations, and has low intrinsic insertion loss. Plural units in series can add/drop plural channels.

Reconfigurable add-drop multiplexer for optical communications systems

A computer system and method provide a CAD tool by which a mask for an application specific optical integrated circuit, chip, or wafer may be generated both easily and quickly. The method involves the step of receiving the design for an optical circuit with the circuit design including at least one optical component. Each optical component in the optical circuit is defined by one or more geometric shapes, such as a trapezoid, rectangle, or an arcuate polygon. The method further includes the step of retrieving parameters which define the manufacturing standard by which the optical circuit will be fabricated as well as parameters which define the optical components in the optical circuit. Based on the parameters and the geometric shapes, a plot is generated which forms a mask layout for the optical circuit. The mask layout can then be viewed by a graphical editor whereby a designer can receive visual confirmation that the mask layout accurately portrays the desired optical circuit, chip, or wafer.

Method and system for generating a mask layout of an optical integrated

A Brag reflective Mach-Zehnder filter has arms that introduce a .pi. phase difference in transmission but not in reflection. In one embodiment a .pi. phase difference is introduced in one of the two arms between the Bragg grating and one of the couplers. In another embodiment, a phase difference of .pi./2 is introduced in one arm both before and after the grating and the location of the grating in the other arm is shifted. The transmission of the resulting filter is substantially independent of the degree of coupling at the input and the output. WDM systems employing the new filters are also disclosed.

Article comprising a Bragg reflective Mach-Zehnder filter of reduced

In accordance with the invention, arrays optical sources are combined in a multilevel planar optical waveguide structure for insertion into an optical fiber laser. The basic element of the combiner is a planar array of multiple waveguides which converge and are gradually tapered to a single output waveguide. A plurality of such elements integrally formed on successive cladding layers provides a high power stack of vertically aligned outputs. An arrangement is described for using such apparatus in the amplification of optical communications signals.

Apparatus for pumping an optical fiber laser

A mechanically stable self-aligned M.times.N optical switch having a low insertion loss is achieved by employing three cleaved silica optical structures containing a plurality of waveguides. A monolithic silica optical structure is cleaved into the three corresponding structures. Each of the first and third structures has a cleaved edge and a respective set of waveguides extending parallel to a corresponding structure surface. The second structure has two substantially parallel cleaved edges and a plurality of sets of waveguides extending parallel to a corresponding structure surface. The corresponding surfaces of the first, second and third structures are positioned on, for example, surfaces of respective first, second and third bases aligned in a common plane. The structures are further positioned with the cleaved edges of the second structure arranged adjacent to and facing respective ones of the cleaved edges of the first and third structures. In operation, the second structure is moveable in a direction along the cleaved edges relative to the first and third structures to selectively align different waveguide sets with the waveguides of the first and third structures to provide various different optical connections between the waveguide sets of the first and third structures.

Self-aligned mechanical M.times.N optical switch

An optimized waveguide structure enables the functional integration of various passive optic components on a single substrate. The optimized waveguide structure is characterized by a thicker core layer than used for square core waveguides and a core width that changes according to different functional regions of the optic circuit within which it is incorporated. The height (H) of the waveguide core is determined by the thickness of the core layer defined during the fabrication process and is ideally uniform across the circuit. The width (W) of the core, however, is changed between functional regions by the photo-lithographic mask and the chemical etching during the fabrication process. By way of example, an optimized waveguide structure for a P-doped silica planar waveguide with a .DELTA. approximately 0.6% for wavelength .lambda.=1.2-1.7 .mu.m, has a single uniform height of H=6.7 .mu.m and a width that changes between W=4 .mu.m in a coupler region, W=5.5 .mu.m in a bend region, W=9 .mu.m in a fiber coupling region, and W=10 .mu.m in a phase grating region of a Dragone router. Adiabatic tapers are used as transition regions between regions of different core widths.

Optimized waveguide structure

The disclosed Mach-Zehnder (MZ)-type devices are planar waveguide devices, with interferometer arms of essentially equal length, with a maximum spacing between the arms (e.g., between the waveguide core centers) selected to make possible simultaneous exposure of both arms to refractive index-altering radiation. Exemplarily the maximum spacing is in the range 20-100 .mu.m. The simultaneous exposure of both waveguides makes it possible to form gratings of essential equal strength, such that typically no individual trimming is required. The resulting devices (typically add-drop filters) are substantially less sensitive to environmental changes (e.g., temperature gradients, mechanical vibrations) than prior art fiber-based devices, and are advantageously used in, for instance, WDM optical communication systems.

Article comprising a planar optical waveguide mach-zehnder

The present invention relates to a waveguide taper. The waveguide taper has a first end and a second end for being coupled with a fiber. The core has an overall width that progressively increases from the waveguide end toward the fiber end such that the width of the fiber end of the taper corresponds to the diameter of the core of the fiber. Side-gaps are disposed in the sides of the core and extend into the core but not across the entire width of the core. The depth of the side-gaps progressively increases from the waveguide end to the fiber end of the taper. In one embodiment, the side-gaps may be aperiodically and/or randomly disposed along the length of the taper and the side-gaps can be disposed at different angles to a direction of light propagation along a length of the core.

Side-gap mode tapering for integrated optic waveguides

In accordance with the invention, a new type of monolithic optical waveguide filter comprises a chain of optical couplers of different effective lengths linked by differential delays of different lengths. The transfer of the chain of couplers and delays is the sum of contributions from all possible optical paths, each contribution forming a term in a Fourier series whose sum forms the optical output. A desired frequency response is obtained by optimizing the lengths of the couplers and the delay paths so that the Fourier series best approximates the desired response. The filter is advantageously optimized so that it is insensitive to uncontrolled fabrication errors and is short in length. The wavelength dependence of practical waveguide properties is advantageously incorporated in the optimization. Consequently, the filter is highly manufacturable by mass production. Such filters have been shown to meet the requirements for separating the 1.3 and 1.551 .mu.m telecommunications channels and for flattening the gain of Er amplifiers.

Monolithic optical waveguide filters based on Fourier expansion

An integrated optical device for tapping signal power provides a tap which is substantially independent of wavelength and polarization. The optical device includes a first tap consisting of a first optical waveguide carrying an input signal S disposed in coupling relation with a second optical waveguide for providing an output cross-state transmission T.sub.1. The cross-state transmission T.sub.1 is polarization and wavelength dependent. The optical device further includes a second tap consisting of a third optical waveguide disposed in coupling relation with and in series with the second optical waveguide carrying the output cross-state transmission T.sub.1 for providing an output bar-state transmission T.sub.2. The bar-state transmission T.sub.2 has an opposite dependency on waveguide coupling than that of the cross-state transmission T.sub.1 and, thus, compensates for wavelength and polarization dependencies of the cross-state transmission signal T.sub.1, thereby providing an overall tap transmission T which is equal to T.sub.1 T.sub.2 and is substantially independent of polarization and wavelength.

Polarization and wavelength independent optical waveguide tap

A waveguide Bragg reflector is made by forming periodic grooves in either the undercladding or the core, applying a high index coating on the grooved surface and selectively removing the coating from the horizontal surfaces while leaving the coating on the vertical surfaces. The waveguide is then completed.

Method for making Bragg reflectors for waveguides

An optical communication network includes a novel, passive optical component. This component combines the function of a splitter with the function of a wavelength-division multiplexer. These functions are performed in distinct wavelength bands. In one embodiment, the inventive component is made using silicon optical bench technology.

Optical network comprising a compact wavelength-dividing component

An optically switches relatively low power requirements and a relatively broad operating bandwidth. This switch includes a Mach-Zehnder interferometer (MZI) optically coupled at respective ends to an input coupler and an output coupler. One arm of the MZI includes a thermo-optic phase shifter. The output coupler is an adiabatic 3-dB coupler. In one embodiment, the input coupler is a Y-branch coupler having one input port. In a second embodiment, the input coupler is an adiabatic 3-dB coupler having two input ports.

Thermally activated optical switch

Growing community of inventors

Skillman, NJ, United States of America

Charles H Henry