Nortel Networks Corporation

Northern Telecom Limited

Keith D Anderson

Richard P Hughes

Douglas S Burbidge

Paul S Ertl

Herman W Willemsen

Sean Sebastian O'Keefe

Kenneth N Grimble

Neil K Balston

An apparatus is disclosed for the aligning of ceramic carrier substrates on base substrates. The apparatus is a gripper having angled faces lined with soft metallic pads embedded with diamonds that engage in a vertical direction with microfeatures in the ceramic carrier of a semiconductor, providing a secure grip throughout alignment and bonding to a base substrate and providing a gentle release upon disengagement. The gripper is typically detachably affixed to a micromanipulator to provide controlled motion and is spring mounted to provide self adjustment to variations in ceramic carrier substrate thickness and angle.

Apparatus for gripping ceramic substrates

To mount two semiconductor optical devices together such that a coupling face of one is aligned with and close to the coupling face of the other the devices are mounted on two different carriers. One of the carriers is flat and has a vertical edge and carries the optical device such that its coupling face is flush with the vertical edge. The other carrier is wedge-shaped and has a vertical edge and carries the other optical device such that its coupling face is flush with that vertical edge. A flat baseplate supports the flat carrier. The wedged carrier is supported on an inclined plane which may be formed on a separate wedge supported on the baseplate or which may be formed as an inclined surface portion on the baseplate. By sliding the flat carrier relative to the wedged carrier and sliding the wedged carrier up or down the inclined plane the coupling faces may be aligned. The application of liquid adhesive facilitates the sliding action and permits easy securing after alignment by curing the adhesive.

Alignment method for semiconductor optical devices upon carriers

The invention relates to a variable optical attenuator having a profiled blade. It includes a mounting base with an actuator formed on the base, the actuator carrying the blade which is moveable across a light beam. The blade is profiled so as to provide a predetermined attenuation of the beam as a function of the displacement of the blade, the function being preferably substantially linear. As a way of example, first and second embodiments of the invention describe an electrostatic comb attenuator made of a semiconductor material and forming a monolithic structure. The embodiments relate to different blade profiles, having a protrusion and a notch at the front edge of the blade respectively. The attenuator device additionally includes light input and output lenses for receiving and directing light along a predetermined optical path. Other known type of attenuators having profiled blades, e.g. thermal, electromagnetic, microgears and piezo-electric, may also be used in modifications to the preferred embodiments described above. If required, the attenuator may be integrated into a package.

Variable optical attenuator with profiled blade

A thermoelectric cooler (TEC) is used to maintain an electronic component, for example, a laser diode, at a set temperature. A thermistor senses the temperature of the laser and through a first control loop causes current to be passed through the TEC so as to adjust the laser temperature. As the temperature of the hot side of the TEC increases above the temperature of the cold side of the TEC, the TEC's cooling efficiency gradually decreases. This is compensated for by adding a second control loop which senses the TEC current and provides an additional gain proportional to the TEC current in the cooling sense. This additional gain is added to the gain provided by the first control loop. The result is a stable, highly responsive temperature controller at all points of the TEC operating range.

Thermoelectric cooler control circuit

Broadband ATM switches for switching ATM packetized data in timeslots are disclosed. In one embodiment, the switch includes input buffer, a space switch for connecting input ports and output ports at successive timeslots and a system scheduler. The timeslot utilization processing is carried out by using a content addressable memory. A bit map is provided for registering the timeslot utilization of the input ports and the output ports. An encoder determines the earliest commonly available timeslot for connecting input ports and their requested output ports. There is further disclosed an architecture in which groups of input ports share common buffer memories and in which the system scheduler processes grouped inputs, thus taking advantage of the architecture's similar characteristics and advantages to those of the common memory switch.

Broadband input buffered ATM switch

A multiple path electro-optic transducer comprises a plurality of electro-optic elements arranged in an array in a device package with electrical connections thereto. A lens tube having a lens, such as a graded index (GRIN) lens, therein is supported so that an axis of the lens is perpendicular to and aligned with the array and so that the array is imaged by the lens in a plane of an outer end of the lens tube. An optical fiber connector comprises a ferrule having a bore therein and a plurality of optical fibers extending through the bore in an array corresponding to the array of electro-optic elements, the ferrule and fibers being positioned, by a cylindrical sleeve over the lens tube and ferrule, so that ends of the fibers lie in the plane of the outer end of the lens tube whereby light emitted by each of the electro-optic element is focused by the lens onto a respective one of the fibers. A mechanical coupling is provided by a bayonet connection between the optical fiber connector and the device package.

Multi-path optical fiber and electro-optic transducer connector

An optical disc assembly has an optical disc and a protective cover. The optical disc has a surface adapted to have optically recorded thereon data consisting of a series of laser ablated pits recorded as a series of concentric data tracks. The pits have small size and high surface density. The protective cover has a permanent optical recording at one surface thereof consisting of a series of visible marks. The marks are an order of magnitude larger than the pits and have a much lower surface density. Memory data is recorded on the optical disc and positional data, comprising a map of the memory data surface, is recorded on the cover. This allows the use of separate positional data and memory data monitoring channels which facilitates the recording of a blank optical disc and subsequent memory data access.

Optical disc having protective cover

In dual wavelength equipment such as a combined read/write unit for an optical disc system, read light of wavelength .lambda..sub.1 is directed through an isolator and a combiner, is reflected from a target back through the combiner and, at the isolator is directed out of the incident beam path to photodetectors. Write light of wavelength .lambda..sub.2 is directed from a position off the read beam path to the combiner where it is re-directed into the read beam path and onto the target. The isolator has a linear polarizer, a polarizing beam splitter, and a retarder functioning together to ensure that at the polarizing beam splitter reflected light is linearly polarized in a direction perpendicular to the incident light. The combiner is typically an interference filter inclined both to the read and write beam path, which transmits .lambda..sub.1 and reflects .lambda..sub.2. Since the filter strongly alters the polarization state of obliquely incident light, a second interference filter located between the polarizing beam splitter and the first filter is used to compensate for the change in polarization state caused by the first filter and by other elements of the optical system.

Growing community of inventors

Nepean, Canada

Keith D Anderson