Abstract: The invention provides a method of generating an alignment feature (200, 300) in an optoelectronic assembly (10, 700) which enables another part, for example an optical fibre (80), external to the assembly to be aligned to a device (40, 400) within the assembly (10, 700) but without needing to be attached to the device (40, 400). The method involves using the device (40, 400) to define a position for its own alignment feature to which the part can register, thereby aligning the part (80) to the device (40, 400). When the device (40) is an emissive device, radiation emitted therefrom is used to delineate a position for the alignment feature. When the device (400) is a detecting device, the feature is defined with assistance of an apparatus (500) whose beam is guided in response to output from the device (400) to delineate a position for the alignment feature.

Abstract: An optical circuit device (1; 1′) has a substrate (6; 5′) with a surface (7; 7′) and a structural discontinuity (17; 17′) in the surface. The surface is provided with a light source (13: 13′) to emit light and a circuit element (15; 15′) whose performance is adversely affected by the incidence thereon of stray light emifted by the light source. To reduce optical cross-talk, the optical circuit device is provided with a barrier element (21; 21′) which is adapted to absorb light emitted by the light source. The barrier element is located in the structural discontinuity and is so positioned as to be able to absorb stray light embted by the light source The optical circuit device may be an optical transceiver having a laser diode and a photodiods.

Abstract: A dispersive optical waveguide device comprising an array of curved silicon rib waveguides providing optical paths in parallel between a first optical coupler at one end of the array and a second optical coupler at an opposite end of the array. The ends of the array waveguides adjacent to the second coupler are distributed around a first arcuate edge of the second coupler forming part of a first circle. A plurality of connecting waveguides terminating at a second arcuate edge of the second coupler face the first arcuate edge of the second coupler. The second arcuate edge forms part of a second circle having a radius of curvature which is half the radius of curvature of the first circle and has its perimeter coincident with the perimeter of the first circle adjacent the ends of the array waveguides.

Abstract: An integrated optical circuit is formed in a silicon layer and supported on a substrate, and a portion of the silicon layer is substantially thermally isolated from the substrate by extending over a recess in the substrate, e.g. in the form of a bridge. Temperature control means are provided to control the temperature of the portion of the silicon layer or of a device provided thereon. A thermal expansion gap may be provided in the portion to accommodate thermal expansion of the portion relative to the substrate.

Abstract: A method of providing a point to point connection between two electrical circuit boards (23, 23′) in which a plurality of pairs of optical transceivers are provided, one transceiver of each pair being formed on a first silicon-on-insulator chip (2) in electrical contact with a first electrical circuit board (23), and the other transceiver of each pair being formed on a second silicon-on-insulator chip (2′) in electrical contact with a second electrical circuit board (23′). Each optical transceiver comprises a branched rib waveguide comprising a common stem (10, 26) and first and second branches (14, 12) extending from the common stem (10, 26); a fiber connector (20) for receiving an optical fiber (22) in communication with the stem (10, 26) of the branched rib waveguide; a light source (4) in communication with the first branch (14) of the branched rib waveguide; and a light receiver (6) in communication with the second branch (12) of the branched rib waveguide.

Abstract: An integrated optical package comprises an integrated optical device in a substantially planar form and a supporting structure, the device being held by the supporting structure in a plurality of fixing regions, the fixing regions being elongate and serving to secure the device in each of the two dimensions of the planar form, at least one edge of the planar form being unfixed. Thus, either two or three edges of the planar form are unfixed, assuming that the device is rectangular. This ensures that one or two edges are free, allowing the device to accommodate stresses by slight relaxation. The device can be held by a heat curable composition, ideally adapted to cure at about the operating temperature of the device. Thus, when the device is operating, the adhesive is substantially at or near its cure temperature. The composition should cure at a temperature within 20° C. of the operating temperature of the device.

Abstract: An optical waveguide, such as a rib waveguide, having a first portion (7) to which a dopant (9) and/or a metal layer (10) is applied to enable an optical property of a second portion of the waveguide to be altered, the first portion (7) having a structure, e.g. being corrugated, the geometry of which is such as to prevent an optical wave being carried in the first portion (7). The dopant (9) and/or metal layer (10) can thus be positioned close to the second portion which carries the optical wave without causing perturbation, e.g. attenuation and/or polarization, of the optical wave.

Abstract: A method of making an optics package is described in which an exposed length of optical fiber is deliberately subject to a predetermined bend. The relationship between the exposed length of the optical fiber and a distance between a location at which it is supported and a fixing point on an optical device is determined taking into account the induced strain in the optical fiber. An optics package designed according to the method is also set forward.

Abstract: Apparatus connecting electrical circuit boards (1, 2, 3, . . . N) so each board can communicate with each other. Each board has an optical circuit, which in turn has a transmitter module (T) and a receiver module (R). The transmitter module (T) has electrical to optical converters (11B) for converting electrical signals into optical signals, a wavelength multiplexer (12) for multiplexing the optical signals into a single optical waveguide (12A), and an optical splitter (13) for dividing the multiplexed signal into a plurality of identical signals for transmission to each of the receiver modules (R). The receiver module (R) has an optical selector (14) for selecting signals from the transmission modules (T), a wavelength demultiplexer (21) for demultiplexing the selected signal into signals each of a different wavelength (&lgr;1 . . . &lgr;n), and optical to electrical converters (22B) for converting each of the signals of different wavelengths into an electrical signal.

Abstract: The application describes the addition of serrations to the edge of the light transmissive layer of an integrated optical device. This enables scattered background light to be coupled out of the device, improving the signal-to-noise ratio.

Abstract: An optical phase modulator comprises a semiconductor rib wave guide having P and N doped regions forming a PN junction along the path of the rib with terminals for applying a reverse bias to the junction to extend a carrier depletion zone to alter the refractive index, the PN junction is offset from the central axis of the rib but on application of the reverse bias the depletion zone extends over a central axis of the waveguide.

Abstract: An integrated optical circuit formed on an optically conductive substrate having light absorbing means comprising one or more doped areas (1) of the substrate where the doping concentration is greater than that of areas of the substrate forming the optical circuit (2) to absorb stray light in the substrate which is not guided by components of the optical circuit.

Abstract: An optoelectronic device is mounted on a planar substrate in electrical connection with solder bumps adjacent an edge of the substrate and connection to a lead frame is made by loading the edge of the substrate on a lead frame support with lead frame conductors in engagement with the solder bumps and applying heat to melt the solder.

Abstract: A thermo-optic semiconductor device has one semiconductor region providing an optical waveguide and an adjacent semiconductor region providing a resistive heater between two doped regions, current may be passed through the resistive heater within the adjacent semiconductor region to heat it and thereby vary the optical characteristics of the waveguide.

Abstract: The device comprises an upper silicon layer (10) including two optically connected rib waveguides (3,4) formed in the upper silicon layer (10); a pair of dissimilar materials (6,7) each positioned between the two waveguides (3,4); and an electrical circuit (8,9,13) through the pair of dissimilar materials (6,7), so that an electrical current can be passed through the dissimilar materials (6,7) in both forward and reverse directions, so as to simultaneously heat one waveguide and cool the other waveguide by virtue of the Peltier effect.

Abstract: An integrated optical waveguide with an end face, the end face being provided on an end portion with a greater width than the waveguide, e.g. in the form of a T-bar provided at the end of the waveguide, whereby the rounding effect produced by the manufacturing process, e.g. etching, used to form the end face does not affect the flatness of the portion of the end face through which light is transmitted. The T-bar is preferably inclined so the normal of the end face is inclined to the optical axis of the waveguide to reduce back reflection therefrom. A plurality of waveguides may terminate in a common T-bar.

Abstract: An optical system comprises two optical paths P1, P2, and an optical path changer for changing the optical length of the two optical paths. The optical path changer includes two phase modulators M1, M2 one coupled to each of the paths. A driving system is configured to apply power to the phase modulators to drive them in the same direction and to change the power applied to the phase modulators in opposite directions so as to change the length of each optical path in a different direction. As a result, the relationship between the changes in the power applied to the phase modulators and the resulting changes in the phase of light beams passing through the optical system becomes substantially linear.

Abstract: A process for treating a waveguide structure which comprises a silicon substrate with an integrally formed rib waveguide is described. The waveguide has an end portion with a facet, the end portion overhanging the silicon substrate and having an oxide layer on its underside protruding from the facet of the waveguide. A nitride layer extends over the upper surface of the waveguide and the facet. The treatment process involves etching the oxide layer from the underside, growing a new oxide layer, etching the nitride layer and then depositing a new nitride layer.

Abstract: A hermetically sealed structure, particularly for use in an optoelectronic device is described. The structure comprises an outer sleeve of a material resistant to moisture ingress with an insert located in the sleeve at one end portion thereof and having a bore therethrough. An optical fibre extends through the bore and beyond the end portion of the sleeve with adhesive films respectively securing the insert to the sleeve and the optical fibre to the insert. A method of assembly for such a package is also described.

Abstract: The present invention is a temperature stable integrated optical device which is substantially insensitive to temperature variations. The device, such as an interferometer, includes sub-sections of a different light transmissive material within the optical pathways. The relative lengths of the two different material waveguides can be selected so as to achieve temperature insensitivity. A suitable balance is to ensure that the ratio of the difference in sub-path lengths of the first and second materials is equal to the ratio of the refractive index gradient with temperature of the second material to the refractive index gradient with temperature of the first material. Preferable materials are silicon and silicon nitride.