Abstract: A waveguide structure for use with a pump laser is disclosed that is designed to counteract the decrease in pump power density. The waveguide structure may comprise an erbium-doped waveguide amplifier, a nonlinear waveguide wavelength converter device, or an optical fiber. The waveguide structure has a waveguide region that is tapered over a pump propagation distance, said distance being defined as a predetermined distance between a first pump site and a second pump site over which the pump light is propagated for signal amplification or conversion. The taper reduces the depletion in pump power as compared with prior art systems and may be kept substantially constant over the pump propagation length, thereby counteracting pump depletion.

Abstract: An optical device that is a waveguide with a heating element thereon that is formed on a silicon substrate is disclosed. The waveguide is formed on a region of porous silicon formed in the silicon substrate. The porous silicon region provides greater resistance to the flow of heat than the silicon substrate on which the device is formed. Optionally, the porous silicon region also provides greater resistance to the flow of heat than the waveguide.

Abstract: A process for fabricating a silica-based optical device on a silicon substrate is disclosed. The device has a cladding formed in a silicon substrate. The device also has an active region, and that active region is formed on the cladding. The cladding is fabricated by forming a region of porous silicon in the silicon substrate. The porous silicon is then oxidized and densified. After densification, the active region of the device is formed on the cladding.

Abstract: In accordance with the invention, an optical all-pass filter comprises a substrate-supported multilayer waveguiding structure comprising a first layer including a waveguiding optical ring resonator, a second layer including an optical grating optically coupled to the ring resonator, and a third layer including a relatively straight waveguide optically coupled to the grating. The waveguide can be made with standard index material matched to an optical communication system, and the ring can be made of higher index material. The grating sandwiched between them provides phase matching between these two index mismatched structures, facilitating efficient power transfer between them.

Abstract: In a time-division-multiplex system, a relatively high-rate optical signal stream comprising multiple interleaved signal sequences is applied to one end of an elongated waveguide that includes multiple photodetectors disposed along the longitudinal extent of the waveguide. Probe pulses at a relatively low rate are applied to the other end of the waveguide in a synchronized fashion to cause two-photon non-linear absorption in successive respective photodetectors as each propagating probe pulse overlaps successive different signals of each sequence. In that way, electrical output signals are provided from each photodetector at the relatively low probe-pulse rate.

Abstract: The specification describes wafer fabrication cleaning processes for silicon optical bench technology. The cleaning processes are designed to remove debris in situ after dicing silicon wafers mounted on a tape carrier. They were also developed specifically to avoid staining and residues that often result from using standard dicing approaches in silicon optical bench integrated circuit manufacture.

Abstract: An improved waveguide optical amplifier having an optically transparent first cladding layer, an optically transparent film doped with an optically active material, disposed over the first cladding layer, at least one undoped optically transparent film disposed over the doped film and coating etched walls of the doped film, and an optically transparent second cladding layer disposed over the undoped film. At least a portion of the undoped film disposed immediately adjacent the doped film has an index of refraction which is closer to the index of refraction of the doped film, than to the index of refraction of the second cladding layer and preferably equal thereto. The undoped film covers surface imperfections in the etched walls of the doped film, effectively moving them from the doped film/undoped film interface to the undoped film/cladding layer interface thereby reducing scattering of the high-intensity mode field.

Abstract: The thermo-optically controlled optical couplers wherein the coupling region between the waveguides in the coupling section is filled with a material having a high dependence of refractive index on temperature thus making the thermo-optic control means more efficient and allowing a greater range of adjustment in the coupling coefficient for a given temperature change.

Abstract: In accordance with a specific deposition/etching sequence, a multi-layer metallization system is formed on the non-planar top surface of a semiconductor wafer. In an electrophoretic deposition step, a conformal uniform-thickness layer of a resist material is then formed on the top surface of the metallization system. In turn, the layer of resist material is lithographically patterned to provide an etch-mask for defining features in the underlying metallization system.

Abstract: Thermal expansion mismatch between solder and substrate can result in substrate cracking, especially in the case of brittle substrates, e.g., Si or glass. This problem can be substantially eliminated through use of a novel bonding pad structure that comprises a sacrificial layer and a confinement layer disposed on the former, with a window through the latter. The confinement layer (e.g., Ti or Cr) is selected to be substantially inert with respect to the solder (e.g, AuSn) at the soldering temperature, and the sacrificial layer (e.g., Au) is selected to interact with the solder at that temperature, such that the molten solder consumes at least some of the sacrificial material, with the interface between the molten material moving laterally underneath the confinement layer. After re-solidification of the molten material the structure effectively has a distributed interface between the resolidified material and the substrate, with attendant decrease of stress in the substrate.

Abstract: During formation of solder bumps on the bonding pads of a component, a two-layer dam structure is utilized to block solder from flowing from the pads to adjacent portions of a metallization pattern. After the solder bumps are formed, the top dam layer is dissolved, whereby any solder debris present on the top dam layer is also removed from the structure. The bottom dam layer, which remains intact during the removal step, serves to confine solder movement during a subsequent bonding operation in which the solder bumps are reflowed to cause them to adhere to aligned pads on another component.

Abstract: An active optical device comprises a glass, waveguiding structure disposed on a substantially planar principal surface of a substrate. The structure includes a silica-based, erbium-doped active core. The active core has an absolute erbium concentration of at least about 0.5.times.10.sup.20 atoms per cubic centimeter, and a radiative lifetime of the erbium lasing level of at least about 5 milliseconds. The active core does not contain significant amounts of alkali metals or alkaline earth metals but does contain at least two modifier metals. Also disclosed is a method for forming an active optical device, including the step of depositing an erbium-doped active core by sputtering.

Abstract: Plural planar optical devices are simultaneously pumped by a single pumping source. Various arrangements for accomplishing such pumping are disclosed. By utilizing these arrangements, the topology and routing of integrated arrays including optical devices are simplified.

Abstract: Plural planar optical devices are simultaneously pumped by a single pumping source. Various arrangements for accomplishing such pumping are disclosed. By utilizing these arrangements, the topology and routing of integrated arrays including optical devices are simplified.

Abstract: Tapered optical waveguides (33') can be easily made by using photolithographic masking and etching to define on a substrate (21) a first polymer structure (22) having a substantially uniform thickness and a tapered width. The first polymer structure is heated sufficiently to form a meniscus along its entire length. The fluidity causes the material to redistribute itself such that, rather than being of uniform thickness, it has a thickness that varies with its width; consequently, the thickness as well as the width of the first polymer structure becomes tapered. The first polymer is cooled and hardened to form a second polymer structure (22') that has a tapered width and a tapered thickness as is desirable for a tapered optical waveguide. The second polymer structure itself can be used as a tapered optical waveguide, or it can be used to control the reactive ion etching of the underlying substrate.

Abstract: We have found that etching of a body that comprises exposed Si as well as a Ti-comprising metal layer (e.g., a patterned Ti/Pt layer) in an amine-based anisotropic etchant for Si (e.g., 100.degree. C. EDP) frequently results in undesirable changes in the Ti-comprising metal layer. We have also found that the changes can be substantially reduced or eliminated by electrolytic means, namely, by making the metal layer the anode in an electrolytic cell that contains the etchant.

Abstract: An active optical device comprises a glass, waveguiding structure disposed on a substantially planar principal surface of a substrate. The structure includes a silica-based, erbium-doped active core. The active core has an erbium-to-silicon atomic ratio of at least about 0.01, an absolute erbium concentration of at least about 1.4.times.10.sup.20 atoms per cubic centimeter, and a radiative lifetime of the erbium lasing level of at least about 7 milliseconds. Also disclosed is a method for forming an active optical device, including the step of depositing an erbium-doped active core by sputtering.

Abstract: The present applicant has discovered that gold can be patterned by masking and reactively ion etching in a CF.sub.4 /O.sub.2 plasma. In accordance with the invention, a layer of gold is patterned by the steps of a) forming a layer of gold on a substrate, b) masking the gold layer to selectively expose a pattern to be etched, c) exposing the masked layer to a CF.sub.4 /O.sub.2 plasma. In preferred practice, the substrate comprises a gallium arsenide substrate having an interface layer comprising titanium to promote adhesion of the gold layer, and the gold layer is formed by sputtering onto the interface layer. The gold layer is masked by photoresist, and the masked layer is exposed to a CF.sub.4 /O.sub.2 plasma with the molar percent of O.sub.2 in excess of about 8%. Advantageously, the exposed intermediate layer can be plasma etched away.

Abstract: An active optical device comprises a glass, waveguiding structure disposed on a substantially planar principal surface of a substrate. The structure includes a silica-based, erbium-doped active core. The active core has an erbium-to-silicon atomic ratio of at least about 0.01, an absolute erbium concentration of at least about 1.4.times.10.sup.20 atoms per cubic centimeter, and a radiative lifetime of the erbium lasing level of at least about 7 milliseconds. Also disclosed is a method for forming an active optical device, including the step of depositing an erbium-doped active core by sputtering.

Abstract: A sol-gel procedure is described for making display devices with luminescent films. The procedure typically involves hydrolysis and polymerization of an organometallic compound together with selected luminescent ions, and coating of a substrate and then heat treatment to form a polycrystalline layer. The procedure is particularly useful for making cathode ray tubes, expecially those for high power operation because of the excellent luminescence characteristics obtained, good thermal contact from the luminescent layer to faceplate and low cost of the procedure. Also described are the devices obtained which exhibit a layer of complex oxide with network structure much like the corresponding bulk compound.