Lucent Technologies Inc.

At&t Bell Laboratories

Other

At+t Corp.

Bell Telephone Laboratories

American Telephone and Telegraph, Co.

Agere Systems Optoelectronics Guardian Corp.

Uziel Koren

Thomas L Koch

Kang-Yih Liou

Rodney C Alferness

Rafael Ben-Michael

Charles H Joyner

Herwig Werner Kogelnik

Chih-Hsiao Chen

Christopher Richard Doerr

Norman Roger Lampert

Nagesh R Basavanhally

Per Bang Hansen

Barry Irwin Miller

Daniel A Fishman

Lawrence Warren Stulz

Henry H Yaffe

Jay Martin Wiesenfeld

Leonard Jan-Peter Ketelsen

John Evan Johnson

Ping K Tien

Jane E Zucker

Dirk Joachim Muehlner

Matthew S Whalen

Gadi Eisenstein

Gerard Edmond Henein

Rodney S Tucker

Lawrence L Buhl

Anat Sneh

Stephen Cason Shunk

Leonard Henri Spiekman

Robert Ewing Behringer

Jane Elisa Zucker

Rudolph Conrad Schweizer

Kevin F Dreyer

Mingdeh Chien

Michael A Newkirk

A hybrid integrated optical transmitter comprising a wavelength selectable laser (WSL) source coupled to an optical amplifier/modulator has been realized. Disposed between the optical combiner and the optical amplifier/modulator is an &ldquo;optical isolator.&rdquo; The optical isolator includes at least a Faraday rotator and, either solely or in combination with a single polarizer and/or half-wave plate is used to selectively rotate and pass polarized light egressing from the wavelength selectable laser source. Optical isolation is achieved by the egressing radiation from and back reflections incident on the laser source being at two mutually exclusive orthogonal polarization states or by the reflections being totally extinguished. Advantageously, the laser source is unresponsive to orthogonally polarized light, and hence any unwanted back reflections do not substantially affect the operating characteristics of the laser(s). Optical isolation may be further improved, however, with the use of an additional polarizer positioned in front of the Faraday rotator to totally extinguish the polarized back reflections. Preferably, a latching Faraday rotator is used. As such, permanent magnets are not needed to maintain the latching Faraday rotator in its saturated state, and substantially reduces cost, size and complexity of the transmitter package. The wavelength selectable laser source is integrated on a single substrate with an optical combiner that directs the radiation to the optical amplifier/modulator, which is integrated on a second substrate. Alternatively, the laser source and optical combiner may be integrated on different substrates.

Hybrid integration of a wavelength selectable laser source and optical amplifier/modulator

A wavelength converter incorporating an on-chip integrated laser for use in an optical system. The converter includes a first port for receiving an optical input signal such as a WDM signal and providing it to an interferometer, and an output port for outputting a signal which is a wavelength-converted version of the input signal. An optical source or laser is fabricated on the chip substrate on which the interferometer is formed for providing operating power to the interferometer. Power levels of the input signal are maintained by adjusting an on-chip semiconductor optical amplifier that receives the optical input signal and provides the amplified signal to the interferometer. In an alternative embodiment, the on-chip optical source is replaced by an on-chip pre-amplifier for an external laser source.

All-optical mach-zehnder wavelength converter with monolithically integrated laser

A unitary two-section semiconductor optical amplifier including a first active region, a second active region, and a passive region integrally connected between the first and second active regions to minimize optical loss therebetween. The arrangement of the two-section semiconductor optical amplifier is advantageous in that the gain in the first active region may be increased in order to maintain a substantially constant input power level to the second active region over a relatively wide dynamic range of input power levels to the first active region.

Two-section semiconductor optical amplifier

A stable single-mode wavelength selectable ring laser operates at a single wavelength which is selectable from any channel passband of a multiple-channel wavelength multiplex/demultiplexer element (e.g., an arrayed waveguide grating router (AWGR)). A Fabry-Perot semiconductor optical amplifier (FP-SOA) is connected together with the AWGR to form a ring laser structure where the FP-SOA is used as an intra-cavity narrow-band mode-selecting filter to stabilize ring laser oscillation to a single axial mode. This is the first time that a FP-SOA is used in a fiber ring laser as a mode-selecting interferometer with gain.

Wavelength-selectable fiber ring laser

An apparatus and method pulses a broadband optical source such as an LED, and generates multiple optical wavelength signals channels which are time division multiplexed onto a single optical channel. The multiple optical wavelength signals may subsequently be modulated by low frequency data signals and then transmitted to a receiver as corresponding multiple independent optical wavelength channels over a single optical fiber. Both spectral slicing and time division multiplexing are accomplished by a wavelength channel defining assembly including a wavelength grating router (WGR) and optical delay lines by using the periodic routing characteristics of the WGR. The WGR separates the broadband optical signal appearing at one input port of the WGR into discrete wavelength bands constituting respective pulses defining the optical wavelength channels by spectrally slicing the broadband optical source frequency spectrum with a multiple channel filter. The WGR then routes each of the wavelength signals to corresponding output ports. Optical delay lines then loop-back the separate wavelength signals from the output ports to other WGR input ports determined according to the routing characteristics of the WGR to multiplex the channels onto a single output port, while also inserting the delay to separate the wavelength signals in time.

WDM transmitter for optical networks using a loop-back spectrally sliced

The invention is directed to an optical transmission system employing an electro-absorption modulator operative that absorbs energy from light received from a source of light and modulates the received light with information signals received from a source of information and outputs the modulated light signal to an optical transmission line, and employing apparatus that controls the level of light signals provided by the source as a function of a control signal having a level proportional to the level of the absorbed energy.

Automatic power control for a wavelength selective EML module

An optical coupling system couples an optical fiber to an optical semiconductor device. A beam expander is disposed within the optical semiconductor so as to receive light from or transmit light into the optical fiber. The coupling is accomplished by disposing a layer of an index matching gel or epoxy on either surface of the semiconductor optical device or the end portion of the optical fiber and another layer of an antireflective material adjacent to the index matching gel or epoxy. The semiconductor device may include an array of optical devices, each coupled to a corresponding optical fiber via the arrangement that comprises the index matching gel and the antireflective material. The semiconductor device may also include an array of waveguides, each configured to receive light from a corresponding optical fiber.

Semiconductor optical waveguide devices with integrated beam expander

Methods and apparatus for performing optical signal switching or other optical routing functions in an optical device or system, in which crosstalk induced by modal interference is suppressed by providing appropriate loss, gain and/or refractive index changes in different parts of a switch structure. An exemplary optical signal switch includes first and second branches each having a refraction-controlled section and an absorption-controlled section. An optical signal path over which an optical signal propagates in passing through the switch is selected to include a portion of at least one of the first and second branches, such that one of the first and second branches is a selected branch and the other branch is a non-selected branch. The refraction-controlled section of the selected branch is configured in a high effective refractive index state which allows the optical signal to propagate along at least a portion of the selected branch, while the refraction-controlled section of the non-selected branch is configured in a low effective refractive index state. The absorption-controlled section of the selected branch is configured in a low absorption state, while the absorption-controlled section of the non-selected branch is configured in a high absorption state to reduce crosstalk within the optical switch. An effective refractive index in a given refraction-controlled section may be provided using electro-refractive techniques such as the quantum-confined Stark effect (QCSE) or the Franz-Keldysh effect, or by carrier-induced effects such as carrier injection or carrier depletion. An absorption change in a given absorption-controlled section may be provided using electro-absorptive techniques or a gain-switching technique. The switch may be configured as a Y-branch switch, a directional coupler, or in other suitable configurations, and may be interconnected with other similar switches to construct 1.times.N, N.times.1, N.times.M and N.times.N switch arrays.

Crosstalk-reduced integrated digital optical switch

The specification describes photonic integrated circuit structures, and methods for making structures in which the active and passive waveguides are coplanar, and further in which all the layers of both the active and passive device regions are essentially coplanar, resulting in a planar surface and design flexibility for contact pad and metallization placement. The fabrication strategy eliminates the deep etch used in conventional processing to form laser devices, and thereby eliminates the step between the laser mesa and the passive waveguide sections.

Manufacture of planar photonic integrated circuits

An apparatus and method provides optical multiple wavelength signals using a single, broadband optical source such, for example, as an LED, to generate many independent optical wavelength channels. An optical transmitter includes a wavelength channel defining assembly which resolves the broad spectrum pulses output by the source into discrete wavelength bands constituting respective pulses (i.e., wavelength channels) and which inserts a delay between the bands to define a sequence of individually addressable channels. In accordance with one embodiment of the invention, spectral splicing is achieved by a multiple channel filter, and insertion of the respective delays is achieved by individual fiber sections, each section having a length selected to introduce a particular delay, coupled to the output ports of the router. The inserted delays can be conveniently selected to separate adjacent wavelength channels and thereby minimize the likelihood of crosstalk. Pulses of the thus-resolved channels arrive at different times to a multiplexer which may be configured, for example, as a passive WDM multiplexer or as a star combiner. The resulting sequence of addressable wavelength channels may be supplied to one or more high-speed, broadband modulators, with each modulator being operable to modulate some or all of the channels.

Optical communication system employing spectrally sliced optical source

An integrated light-emitting device has a laser section and a detector section. The laser section and the detector section have an active layer that is integrated along an in-line waveguide. The detector section also has a bulk layer adjacent to the active layer, where the bulk layer has a band gap energy lower than the band gap energy of the active layer. In one embodiment, the active layer is an multiple quantum well (MQW) layer, the waveguide has two quaternary layers, and the bulk layer is a bulk quaternary layer. The device, which has uncooled modes of operation for both transmitting and receiving, may be used as a transceiver in a ping-pong optical data link configuration. The device may also have a beam expander section, with the laser, detector, and beam expander sections inside a Fabry-Perot cavity, along the single in-line waveguide. In one embodiment having a 1.3 .mu.m lasing wavelength, the addition of a 1.4 .mu.m bulk quaternary layer provides the detector with a broad spectral responsivity range extending 33 nm higher than the lasing wavelength of the device. This permits uncooled operation of the device with sufficient response even in the most severe temperature scenarios that would typically occur. The transmitter can provide 8 dBm inside a single mode fiber, and the beam expander relaxes the alignment tolerance, using a cleaved rather than a lensed single mode fiber.

Detector for photonic integrated transceivers

A laser mounting configuration and method that enables a laser to be mounted onto a substrate in an orientation that passively aligns the laser with and adjacent optical fiber or optical waveguide. In an application with an optical fiber, a structure is formed in the substrate to retain the optical fiber at a fixed position. Ridges are formed in the substrate at a known orientation with respect to where the optical fiber is held. When the laser is applied to the substrate, the ridges on the substrate engage grooves formed on the bottom of the laser, thereby orienting the laser. In an application with an optical waveguide, a trench is formed in the substrate. The optical waveguide is formed partially within the trench so that the core of the waveguide is at the same height as the active layer of the laser when the laser lays flush on the substrate. Alignment stops are formed on the substrate at predetermined positions with respect to the waveguide. When the laser is brought into abutment with the alignment stops, the laser becomes properly aligned with the core of the optical waveguide.

Apparatus and method for mounting a laser to a substrate and aligning

The present invention is directed to a semiconductor waveguiding structure which includes a) a first semiconductor waveguiding layer formed on a substrate, b) a barrier layer that is formed on the first semiconductor waveguiding layer, and that is resistant to a selected etchant, and c) a second semiconductor waveguiding layer that is etched using the selected etchant such that its width is tapered along its length to a pointed edge. A separate etching of the first semiconductor layer is performed to form each sidewall of the first semiconductor layer. The intersection of those sidewalls defines the pointed edge which has a radius of curvature of less than 500 Angstroms.

Tapered beam expander waveguide integrated with a diode lasesr

A connector assembly for coupling an optical fiber to an active optical device has a metal sleeve and an L-shaped alignment block having perpendicularly disposed reference surfaces. A resilient member on the sleeve biases an optical fiber terminating plug against the reference surfaces. The active optical device is attached to a ceramic sub-mount and the sub-mount is placed on one of the reference surfaces. The sub-mount is sized so that an optical port for the active optical device will become aligned with the central axis of the plug. To couple the optical fiber with the active optical device, the plug is slid into contact with the active optical device and is rotated until the fiber is substantially registered with the optical port. The sleeve may have a second resilient member for receiving another plug from the opposite end of the sleeve with a fiber in the other plug being coupled to a second optical port. The active optical device can comprise a variety of devices, such as a laser or an optical modulator with mode field beam expanders.

Fiber and active optical device interconnection assembly

Tapered beam expander waveguide integrated with a diode laser

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Fair Haven, NJ, United States of America

Uziel Koren