Abstract: A group of diode lasers emitting beams at a first wavelength is positioned above and below a stack of laser diodes emitting beams at a second wavelength. The first wavelength beams are directed to a dichroic portion of a compound prism and are reflected outwardly. The second wavelength beams are directed to the opposite surface of the dichroic portion but pass through without reflection and so are directed into substantially the same outward plane as the first wavelength beams. The compound prism combines beams of two different wavelengths to achieve a greater power density in the given plane than can be obtained with beams of either wavelength alone.

Abstract: A wafer supporting a semiconductor structure having a material gain function that would preferentially support an F-P laser mode at an unwanted wavelength &lgr;2 is provided with a second order dielectric grating located sufficiently remotely from the high intensity optical field of the quantum well and the waveguide to receive just enough transverse mode energy to provide feedback to reduce the gain at &lgr;2 and support oscillation at a desired wavelength &lgr;1. More particularly, by providing a gain discrimination factor &agr;≈0.1 cm−1, the fraction of power lost to transverse mode radiation can be held to about 1% which is sufficient to provide stabilizing feedback without sapping too much energy from the longitudinal beam.

Abstract: A printed circuit board is made of a light transmitting material and is used as a waveguide for light. The board may be coated on both surfaces with a light-reflecting material to improve waveguiding properties. Such a board is operative to replace the microlens and optical fiber common in laser diode packages to form an optical path to deliver optical energy to some sensor position. A sensor of optical energy need only be coupled to a window in one of the coatings or positioned at the edge of the board.

Abstract: Laser diodes are formed using composite material systems which result in the decoupling of the refractive index and band gap profiles of the structures formed with such systems. Laser diodes with composite material systems are described which produce desirable large diameter laser beams and low beam divergence through independent control of the two profiles.

Abstract: A GaInAsP/AR GaInP laser diode is provided with an AlGaAs type II carrier blocking layer in the waveguide of the diode. The resulting diode exhibits a relatively low threshold current, an increased slope efficiency and characteristic T0 and T1, for the diodes are less limited by carrier leakage.

Abstract: A substrate comprising, for example, a copper-beryllium oxide ceramic-copper sandwich permits a laser diode along with cooperative components to be soldered in place using a high temperature solder. The sandwich structure is operative to move the effective thermal properties of the copper more towards that of the beryllium oxide thus reducing, for example, any stress which might occur between the solder, the substrate, and the laser diode. The use of high temperature solder provides for significantly improved operation.

Abstract: Semiconductor laser diodes or diode bars are assembled into stacks by a method which permits testing of an entire stack at once and which uses only high temperature solder. The stack includes a plurality of submounts which resemble elongated bars which are square in cross section. Laser diodes (or diode bars) are sandwiched between adjacent submounts. Each submount has an elongated mesa and the mesas are so shaped and positioned in the stack to form a set of ridges which fit into a set of grooves in a substrate. The diodes are bonded to adjacent submounts in a stack simultaneously by reflowing solder preforms (high temperature) in a reflow oven. The stack is secured in place in the grooves of the substrate by reflowing solder placed at the bottom of the grooves.

Abstract: Diffusion bonding techniques are extended to the simultaneous bonding of an array of multilevel piece parts. The problems of uneven expansion and contraction of different levels of different piece parts in the array are obviated by positioning each level of the array within a frame. The stack of frames is pinned in one corner. The opposite corner of the array has a slot at a 45° angle with respect to the x and y axes of the array. The slot engages a pin and allows the entire array to expand and contract along the slot in a manner to maintain the registration of features between respective levels of each piece part.

Abstract: Multi-layer, semiconductor devices are configured to reduce stress by the removal of much of the structure which does not actually contribute to device performance. In one embodiment, trough between mesas which define light emitting facets in a laser diode bar are etched well into the substrate to remove all layers of different compositions there. In another embodiment, troughs are also etched in the backside of the substrate of a laser diode structure where the troughs are aligned along axes perpendicular to the axes of the mesas. The removal of stress permits more accurate alignment of the multiple facets along a single axis when the laser bar is bonded to a heat sink. The accurate alignment minimizes the placement constraints on the position of a microlens for achieving maximum power output and coupling efficiency for optical fibers coupled to the microlens.

Abstract: A plate of metal is bonded to a plate of and electrical insulator and the metal is cut through into a plurality of parallel channels, or recesses, each of a dimension to receive a laser diode (bar). A laser diode is positioned in each of the channels and a solder preform, positioned on the top of the laser diode bars. Is heated to flow around each laser diode bar to secure it in place. A highly manufacturable laser diode assembly having a higher heat capacity results for bonding to a heat sink.

Abstract: Quantum well lasers are herein made with purposely-graded interfaces which control the interdiffusion of atoms during high temperature processing. The result is a predictably-graded, large interface between the quantum well and the waveguide layers to either side thereof. The process is highly controllable and produces unique structures which exhibit surprisingly high power in a repeatable manner.

Abstract: Square cross section optical fibers are accurately positioned for coupling light from laser diode emitting facets through a fiber lens. The fibers are placed in parallel channels formed in a photolithographic layer on a planar surface of a substrate and constrained in place by a retention plate. The fibers extend beyond the retention plate unrestrained by photoresist but overlying the exposed portion of the planar surface of the substrate. The fibers over the exposed portion are cemented in place and the photoresist layer is then removed leaving the constrained portion of the fibers in very accurately defined positions, and free of epoxy cement, for abutment to the familiar fiber lens.

Abstract: Protection from current and voltage spikes is provided for a laser array by attaching a reverse diode laser array to shared contact pads before the first laser array is bonded to those pads. The arrangement provides for surge protection even during fabrication of the laser package where device failure results from power surges before surge protection circuitry is in place. Surge protection is afforded by having a reverse diode of the reverse diode array electrically in parallel with a corresponding laser diode of the protected array when activated.

Abstract: An InGaAsP/AlGaAs/GaAs heterostructure laser diode includes an InGaAsP quantum well and at least a cladding region of AlGaAs while essentially avoiding the deleterious effects attributed to the presence of Al in heterostructure laser diodes. Embodiments with Al present in the cladding region and with Al present in both the waveguide and the cladding regions are described.

Abstract: Damaged automobile windshields are removed using an array of laser diodes. The diodes are chosen to provide light energy at a wavelength to be focused on and absorbed by the ceramic layer coating the windshield edge and to which is bonded the adhesive layer which holds the windshield in place. In practice, the diode array is moved along the windshield edge directing light through the windshield at the ceramic layer. The laser array comprises a linear array of diodes, having a length to span the width of the adhesive band.

Abstract: The cavity of a laser diode is made longer than that which would be dictated by consideration of maximizing the efficiency of the diode. The lateral divergence of the emitted light beam is decreased as the cavity length increases. The lower lateral divergence enables the emitted light beam being focused to produce a greater depth of field for coupling into an optical fiber. In another case, when the fiber size is fixed, lower lateral divergence enables the emitted light beam to being fed into a lower numerical aperture fiber, or enables the beam divergence after fiber to be lower.

Abstract: A laser diode structure includes a metallic gasket which is sandwiched between the laser diode submount and the backside electrode in the absence of solder interfaces. The gasket has mirror image, shallow recesses in the surfaces thereof with each surface having the general shape of a wing. The recesses are formed into sealed coolant conduits when the several layers are bonded together into an integrated structure. The narrow end of each recess communicates with an aperture through the adjacent layer to provide inlet and outlet ports for the coolant. The gasket has an aperture therethrough at the wide ends of the recesses for the coolant to circulate. The gasket can be formed from a single layer or from two layers each with a single recess.

Abstract: An assembly of simple, like laser diode submounts or laser diode bars lend themselves to volume manufacturing techniques. Individual diodes, or diode bars are supported on electrically-insulating submounts which have electrically-isolated metallizations applied thereto for mounting on a single insulating plate and to one another in a stack and for mounting to a common heat sink.

Abstract: A reduced, lateral mode laser diode is fabricated using a self-aligning process which produces a well controlled weakly index-guided waveguide with strong current confinement. The structure includes ion implants for controlling current injection into the active region from the top of the ridge. The number of modes may be reduced to unity, resulting in a single lateral mode laser. A laser diode array is fabricated in the same way.

Abstract: A laser package includes a housing and a subassembly to which the critical components of the laser package are mounted. The subassembly is structured to preserve component alignment even in the presence of thermal excursions by ensuring that any movement which might occur effects all the components in a way to preserve alignment. The subassembly is easily removable from the housing and thus permits replacement if a failure should occur. A reverse diode is included to provide a path for reverse currents which otherwise would be damaging to the active laser diode.