Sdl Inc.

Spectra Diode Laboratories, Inc.

Jds Uniphase Corporation

Eastman-Kodak Company

John G Endriz

David F Welch

Donald R Scifres

Steven Sanders

Edmund L Wolak

Dirk J Kuizenga

Richard R Craig

Robert J Lang

Robert G Waarts

Julian S Osinski

D Philip Worland

James M Haden

Michael P Staskus

Robert Lg Waarts

David D Kessler

William Streifer

Gary L Harnagel

William Streifer, Deceased

Alexander Schoenfelder

Robert L G Waarts

Gerald S Browder

Mitra Ahrabi

G Rainer Dohle

David D Dawson

Jose Chan

Laser modules that are operated intermittently are prone to stop operating after only a few thousand cycles or less. The laser modules sometimes experience a significant increase in operating temperature before they stop operating and, in some cases, manifest an opening of the electrical circuit that connects the laser diodes in the stack of laser subassemblies. In extreme cases, the laser module disintegrates into component subassemblies. These problems arise from structural failures in affixing agents like solder that are used to affix component parts to each other. The structural failures are caused by cyclical thermal expansion and contraction of component parts that exceed the elastic limit of the solder. Resistance to global plastic deformation (creep) and to local plastic deformation (fatigue) is improved by selecting materials to reduce mechanical strain and increase resistance to creep and fatigue, by altering the structural design of the laser module to reduce mechanical strain induced into the affixing agents, and by altering operational practices to reduce the range of temperatures imposed on laser module components. One design method improves resistance to creep and fatigue by controlling the thickness of the affixing agents used to affix component parts to each other.

Solder and material designs to improve resistance to cycling fatigue in laser diode stacks

A multistage optical amplifier pumping system with built-in redundant reliability for lightwave communication system provides plural levels of redundancy. A first level of redundancy deals with redundancy in the form of plural primary laser diode sources for pumping a single fiber laser pump source. A second level of redundancy deals with redundancy of a plurality of fiber laser pump sources for pumping a plurality of serially connected injection signal fiber amplifiers forming the multistage amplifier system. If one of fiber pump sources should fail, increased pumping power is available from the remaining fiber pump sources via their respectively connected amplifier stages. A third level of redundancy deals with redundancy in the employment of multiple single mode laser emitters on the same chip or bar sufficiently segmented and/or electrical isolated so as not to interfere with operation of or cause failure to adjacent or neighboring emitters on the same chip or bar.

High power, reliable optical fiber pumping system with high redundancy for use in lightwave communication system

A power system for a laser source comprises a plurality of semiconductor lasers or at least one laser array with plurality of independently, electrically addressable emitters. A power supply is independently connected to each of the laser emitters. A fuse device is associated with each of the laser emitters so that an electrical short of any one emitter of a laser will not cause a short to or change the power supplied to other emitters of the laser source.

High power, reliable optical fiber pumping system with high redundancy for use in lightwave communication systems

The invention relates to laser diode arrays having high beam quality and high beam brightness. In one approach, a laser diode array package includes a mount and first and second laser diode arrays disposed on the mount. Each of the laser diode arrays defines an optical axis and has an emitting surface lying in an emitting surface plane. The emitting surface plane of the first laser diode array is displaced relative to the emitting surface plane of the second laser diode array in a direction parallel to one of the optical axes. The optical axes of the first and second laser diode arrays are offset from each other in a direction perpendicular to one of the optical axes. First and second lenses are disposed relative to respective emitting surfaces to reduce divergence of light output from the emitting surfaces. In another approach, laser diode array bars are stacked and the individual output beam from each bar is collimated using a short focal length, low aberration lens. The resulting collimated beams are treated with reflectors to reduce, or remove, the dead spaces between adjacent collimated beams, thus permitting the use of low aberration lenses, which results in an improved divergence-size product for each beam produced by a bar. Additionally, the total beam output by the array of laser bars is condensed in size.

Laser diode array assemblies with optimized brightness conservation

Coherent light sources combining a semiconductor optical source with a light diverging region, such as a flared resonator type laser diode or flared amplifier type MOPA, with a single lens adapted to correct the astigmatism of the light beam emitted from the source is disclosed. The lens has an acircular cylindrical or toroidal first surface and an aspheric or binary diffractive second surface. The first surface has a curvature chosen to substantially equalize the lateral and transverse divergences of the astigmatic beam. Sources with an array of light diverging regions producing an array of astigmatic beams and a single astigmatism-correcting lens array aligned with the beams are also disclosed. The single beam source can be used in systems with frequency converting nonlinear optics. The array source can be stacked with other arrays to produce very high output powers with high brightness.

High brightness laser diode source

An optical amplifier pumping system with built-in redundant reliability for lightwave communication system provides plural levels of redundancy. A first level of redundancy deals with redundancy in the form of plural primary laser diode sources in the lightwave communication system. A second level of redundancy deals with redundancy of multiple single mode laser emitters on the same chip or bar sufficiently segmented so as not to interfere with operation of or cause failure to adjacent or neighboring emitters on the same chip or bar. A third level of redundancy deals with redundancy of a plurality of fiber pump sources for pumping a plurality of serially connected injection signal fiber amplifiers.

High power, reliable optical fiber pumping system with high redundancy

A system and method for operating a high power laser diode device with high efficiency coupling of a laser diode bar. The laser diode bar and a micro-cylinder lens are vertically oriented in a device package, such that the array axis of the laser bar and the longitudinal axis of the micro-cylinder lens are aligned substantially parallel to a gravity vector. In the two different embodiments disclosed, either initial collimation of the fast-axis divergence or, alternatively, initial collimation of both the fast-axis and slow-axis divergences take place before beam reformatting via a beam array turning mirror. Additionally, the vertical orientation of these components is combined with methods of compensating for the bending or 'smile' of the laser diode bar to provide for optimal output beam coupling, resulting in a uniform far field intensity distribution.

Packaged laser diode array system and method with reduced asymmetry

A high-power two-dimensional edge-emitting diode laser array comprises mounting modules, laser bars mounted on the modules, and protective caps mounted on the bars opposite the modules. The lasers are electrically connected in series through the modules and caps. The caps serve as laser bar protectors during the bar burn-in. The caps have grooves which compensate for tolerances in the thicknesses of the lasers, modules, and caps. The array is mounted on a base plate, and is in thermal communication with a heat sink. The caps and/or modules are thermal-expansion-matched to the laser bars. Eliminating the need for a wire bond plate allows shortening the modules.

No wire bond plate (NWBP) packaging architecture for two dimensional

A diode laser source including a laser diode whose emitting element array or elements or subarray is divided into a plurality of concurrently driven laser segments. Beam filling and focusing optics are disposed in front of the segments so that light from the segments in each element or subarray converges to a single overlapping spot. The optics include a beam filling lens array collimating the light from the segments and either a single focusing lens or a second lens array focusing the collimated light to corresponding spots. In the case of a element laser diode array, each multi-segment element or subarray of the array is individually addressable so as to be driven independently from the other multi-elements array elements. The segmentation of laser elements improves laser life by reducing thermal gradients and isolating any local failures to a single segment, while separately focusing of the segments of each subarray to overlapping light spots increases the tolerance of the source to local failures. Two or more segments in a given element or subarray must fail before the source is considered to fail.

Diode laser source with concurrently driven light emitting segments

A method of producing a high power and brightness beam from diode laser source that either has a single emitting element or array with a plurality of segments or emitters that are concurrently addressable, or has a plurality of elements or subarrays each having a plurality of laser segments or emitters, which elements or subarrays are independently addressable relative to one another. Beam filling and focusing optics are disposed in front of the emitters so that light from the individual emitters from each subarray converge to from a single overlapping spot. Segmentation of laser subarrays and emitters improves laser life by reducing thermal gradients and isolating any local failures to a single segment emitters, while the focusing of the segments or emitters to overlapping light spots increases the tolerance of the source to local failures. Two or more emitters in a given element must fail before the source is considered to have failed.

Method for producing a highpower beam from a diode laser source having

An optical amplifier pumping system with built-in redundant reliability for lightwave communication system provides plural levels of redundancy. A first level of redundancy deals with redundancy in the form of plural primary laser diode sources in the lightwave communication system. A second level of redundancy deals with redundancy of multiple single mode laser emitters on the same chip or bar sufficiently segmented so as not to interfere with operation of or cause failure to adjacent or neighboring emitters on the same chip or bar. A third level of deals with redundancy of a plurality of fiber pump sources for pumping a plurality of serially connected injection signal fiber amplifiers.

A laser multibeam printer or recorder includes a laser diode array generating multiple modulated parallel and diverging light beams with predetermined light intensities at any instant of time. Optical means reduce the divergence of the parallel light beams from the laser diode array by a predetermined amount, do not focus the light beams in a first cross-section direction along a width of the laser diode array, and focus the light beams onto a plane of an entrance pupil of a printing lens in a second cross-sectional direction normal to the first cross-sectional direction. A separate lenslet of a lenslet array directs a corresponding light beam from the laser diode array towards a predetermined area on a plane in front of the printing lens (e.g., the entrance pupil) in the first cross-sectional direction, and focuses the light beam onto the plane of the entrance pupil in a second cross-sectional direction. The printing lens images the light beams at the entrance pupil onto a light sensitive media as a corresponding array of closely-spaced spots of data with predetermined intensities. Various other arrangements using a field lens in combination with the lenslet array with or without a micro lenslet array can be used to process light beams and form an image of closely-spaced spots of light on the light sensitive media.

Optical means for using diode laser arrays in laser multibeam printers

In an optical transmission medium, such as a fiber amplifier, two optically distinguishable signals with complementary modulation are both inputted into the amplifying medium for encoding information, particularly a serial stream of digital data, or alternatively, redundant encoding of pulses. The gain profile in the medium is preferably maintained approximately constant at all times, so that whichever amplified signal is used as the primary information carrier, its output intensity will be substantially stable from pulse to pulse, independent of recent pulse history. The two complementary signals may have different orthogonal linear polarizations or wavelengths with the same stimulated emission cross-section, so that the population inversion profile stays constant, whichever signal happens to be on at a given moment. The two signals may be derived from separate intensity modulated laser diode signal sources, from a single laser diode signal source switched between two emission wavelengths, or from a single laser diode with constant emission coupled to a directional coupler directing two complementary polarized light signals into the fiber amplifying medium.

Optical amplifier with complementary modulation signal inputs

A diode laser source including a laser diode whose emitting element or elements is divided into a plurality of concurrently driven laser segments. Beam filling and focusing optics are disposed in front of the segments so that light from the segments in each element converges to a single overlapping spot. The optics include a beam filling lens array collimating the light from the segments and either a single focusing lens or a second lens array focusing the collimated light to corresponding spots. In the case of a multi-element laser diode array, each multi-segment element of the array is individually addressable so as to be driven independently from the other array elements. The segmentation of laser elements improves laser life by reducing thermal gradients and isolating any local failures to a single segment, while the focusing of the segments to overlapping light spots increases the tolerance of the source to local failures. Two or more segments in a given element must fail before the source is considered to fail.

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Belmont, CA, United States of America

John G Endriz