Sdl Inc.

Jds Uniphase Corporation

Julian S Osinski

Robert J Lang

David F Welch

Robert G Waarts

Donald R Scifres

John G Endriz

Edmund L Wolak

Randall S Geels

David G Mehuys

Stephen A O'Brien

Kenneth M Dzurko

Mats A Hagberg

A light emitting device, such as semiconductor laser diodes, superluminescent devices, semiconductor amplifiers and polymer-based light emitting devices, is provided with a coating that will increase the thermal conductivity at one or more facets of the device to provide for lowering the facet temperature during device operation to suppress the occurrence of temperature dependent facet degrading mechanisms and the catastrophic optical damage (COD) level of the light emitting device since these facet attributes are directly affected by temperature at the facet. In the preferred embodiment, the coating should have a thermal conductivity that is higher than the material of the light emitting device. The high thermal conductivity coating provides for an efficient transfer of heat away from the beam emission area of the front facet into regions adjacent to, i.e., above or below the active region of the device, such as layers of the device underlying the active region and the device substrate. If the coating material does not provide a sufficiently high level of thermal conductivity, then thermal resistance should be taken into consideration and the coating should be made thicker to achieve lower thermal resistance and, therefore, higher heat spreading toward lowering the facet temperature. In either case, the rate of heat transfer from the facet is enhanced so that the onset of higher temperature dependent facet degrading mechanisms and COD developing at the device facet are reduced or suppressed.

Thermally conductive coatings for light emitting devices

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

As to a first feature, a semiconductor optoelectronic device includes a resonator having an optical cavity between opposite end facets, a larger portion of a length of the resonator cavity comprising a single mode confining region for propagation of light and a smaller portion of a length of the resonator cavity comprising a tapered region for permitting propagation of light with a diverging phase front to a first of the end facets, which first facet is the light beam output. The tapered region provides a sufficiently large aperture to prevent catastrophic optical mirror damage (COD) at the first end facet while reducing the amount of required astigmatism correction while the single mode confining region provides spatial filtering to maintain diffraction-limited beam at the output. This structure therefore, more readily lends itself for incorporation into existing device packages designed for linear stripe laser diodes devices. As to a second feature, a semiconductor optoelectronic device includes a gain region having a region permitting propagation of light with a diverging phase front to a first end facet of the device, which is its output, and a single mode region is coupled to an inner end of the gain region extending from the inner end to a second end facet of the device permitting propagation of light with an adiabatic phase front to the second end. The significantly smaller taper of the single mode region permits retained maintenance of single mode operation while reducing optical density of the propagating beam at the second end facet.

Flared semiconductor optoelectronic device

A surface of a compound III-V semiconductor device is passivated and protected, respectively, by treatment with a sulfur-containing or selenium-containing passivation film on the surface followed by the deposit of a GaN, GaP, InGaP, GaAsP, ZnS or ZnSe protection layer. Prior to passivation and deposition of the protective layer, previously formed contact metalizations may be protected with a liftoff film or layer. A low temperature MOCVD process is used to deposit the protection layer so that the integrity of the previously deposited contact metalization is maintained. The preferred range for MOCVD deposition of the protection layer is in the range of about 300.degree. C. to about 450.degree. C. This processing temperature range is within a temperature range where stable contact metalization exists.

Passivation and protection of semiconductor surface

Passivation and protection of a semiconductor surface

A semiconductor light amplifying medium has reduced self-focusing and optical filamentation for providing higher power coherent outputs in broad-area laser and amplifier devices. In one embodiment, a longitudinally inhomogeneous active region has alternating segments of first gain portions and second compensating portions. The compensating portions have a negative self-focusing parameter [.differential.n/.differential.P] and may be light absorbing (negative gain) regions with negative antiguiding factor .alpha. or light amplifying (positive gain) regions with positive antiguiding factor .alpha.. The .alpha.-parameter is defined as the ratio of refractive index change per change in gain, as a function of carrier density. In a second embodiment, the medium may have longitudinally varying peak filament period so that filaments beginning to form in one portion of the active region are subsequently dispersed in a succeeding portion, slowing filament growth. In addition to self-focusing compensation, media with a lower .alpha.-parameter are provided by increasing the barrier height in quantum well active regions, straining or p-doping the active region, or a combination of these methods.

Semiconductor optical amplifying media with reduced self-focusing

A phased array of flared amplifiers fed by phase adjusters and a power splitter produces a single high power beam when the flared amplifier sections are aligned and closely spaced. In one embodiment the array is excited by a DBR laser integrated into the same substrate as the flared amplifiers. In another embodiment the array is self-excited and forms a laser between an edge of the substrate common to the power splitter and an edge of the substrate common to the flared amplifier.

Growing community of inventors

Palo Alto, CA, United States of America

Julian S Osinski