Oclaro Technology Limited

Meritor Heavy Vehicle Systems Limited

Lucas Industries Public Limited Company

Lumentum Technology UK Limited

Lucas Industries Limited

Arvinmeritor Gmbh

Bookham Technology Limited

Meritor Heavy Vehicle Braking Systems (uk) Limited

Oclaro Technology Limted

Arvinmeritor Heavy Vehicle Braking Systems (uk) Ltd.

Andrew John Ward

Denis John McCann

Douglas Charles John Reid

Andrew Cannon Carter

Neil David Whitbread

Samuel Davies

Sam Davies

David Charles Hurst

David James Robbins

Giacinto Busico

Franz Helmut Holl

Malcolm Brearley

Martin Pors Taylor

Robert Anthony Griffin

Wilfried T Giering

Dietmar Knoop

Paul Anthony Thomas

Mark Anthony Norman

Stephen K Jones

Carl Edward Heinlein

Robert Graham Walker

Denis J McCann

Lloyd Nicholas Langley

Dennis John McCann

Roberto Conti

Jonathon Leslie Christopher Jackson

Markus Necknig

Douglas Reid

Martin Bissell

Paul Antony Fawkes

Guy Towlson

Stuart B Dawson

David Williamson

Stefano Cattaneo

Andrew Moseley

Ian Douglas Poole

Michael Jones

An optical transmitter comprises a directly coupled MZ interferometer and driver circuit. The MZ interferometer comprises a pair of differentially driven MZ electrodes configured to impart RF signals to light travelling through respective arms of the interferometer, and to receive DC bias as a positive voltage via lower n-type cladding of the MZ interferometer. The lower n-type cladding is at a different positive DC potential to an upper plane RF ground of the MZ interferometer, but the lower n-type cladding and the upper plane RF ground have similar AC potential. The MZ interferometer also comprises a pair of resistors in series configured to provide differential RF termination of the MZ electrodes; and a capacitive coupling between a virtual ground formed at a centre point between the pair of resistors and an RF ground configured to provide common-mode RF termination. The DC supply for the driver circuit is applied to the centre point of the RF termination.

Biasing method for InP Mach-Zehnder modulators directly coupled to RF driver circuits

The invention relates to optical modulation devices and, in particular, monolithically integrated optical modulation devices. Disclosed herein is a monolithically integrated optical modulation device () that comprises: an input optical port (); an output optical port (); and an optical waveguide for guiding light from the input optical port to the output optical port. A portion of the optical waveguide is split into at least two branches. The waveguide is configured to cause a net 180&#xb0; change in direction of the light while guiding said light from the input optical port to the output optical port such that the input optical port and the output optical port are positioned on a first edge of the device. At least some of the net 180&#xb0; change in direction is achieved within the branches of the waveguide.

Optical modulation device

There is disclosed a DBR laser and a method of use. The DBR laser comprises a phase section in a cavity of the DBR laser and configured to adjust an optical path length of the cavity. A DBR section comprises a frequency tuning system configured to adjust a Bragg frequency of the DBR section. A detector is configured to detect laser light transmitted through the DBR section. A controller is configured: to cause the phase section to apply a dither to the optical path length of the cavity or cause the frequency tuning system to apply a dither to the Bragg frequency of the DBR section; to use the detector to monitor intensity of light transmitted from the laser cavity via the DBR section during application of the dither; to determine a deviation from longitudinal mode centre operation on the basis of the monitored intensity; and to cause the frequency tuning system to adjust the Bragg frequency of the DBR section in order to reduce said deviation, or cause the phase section to adjust the optical path length of the cavity in order to reduce said deviation.

Active mode centre control

A semiconductor distributed Bragg reflector laser configured for single longitudinal mode operation, having an optical waveguide comprising an optical gain section, a first reflector being a first distributed Bragg reflector (DBR) section comprising a grating configured to produce a reflection spectrum having one or more first reflective peaks, and a second reflector, wherein the first DBR section is configured to compensate for thermal chirp that is induced inhomogeneously along the length of the DBR section, in use.

Semiconductor DBR laser

A monolithically integrated, tunable semiconductor laser with an optical waveguide, comprising epitaxial layers on a substrate and having first and second reflectors bounding an optical gain section and a non-driven region, wherein at least one of the reflectors is a distributed Bragg reflector section configured to have a tunable reflection spectrum, wherein control electrodes are provided to at least the optical gain section, and the distributed Bragg reflector section, and wherein the non-driven region has a length of at least 100 &#x3bc;m, is without an electrical contact directly contacting onto the epitaxially grown side of the non-driven region, and the non-driven region is without a reflective Bragg grating within the epitaxial layers of the non-driven region.

Monolithically integrated tunable semiconductor laser

A monolithically integrated, tunable semiconductor laser with an optical waveguide, comprising a laser chip having epitaxial layers on a substrate and having first and second reflectors bounding an optical gain section and a passive section, wherein at least one of the reflectors is a distributed Bragg reflector section comprising a grating and configured to have a tunable reflection spectrum, wherein the laser is provided with a common earth electrode, wherein control electrodes are provided on the optical waveguide in at least the optical gain section and the at least one distributed Bragg reflector section, wherein the passive section is provided with an electrode or electrical tracking on the optical waveguide, the passive section is configured not to be drivable by an electrical control signal, and no grating is present within the passive section.

An adjustable array includes a plurality of optical devices. Each adjustable array device has an optical light output therefrom and is configured whereby the corresponding optical lights of the plurality of optical devices have a predefined nonequivalent relationship relative to one another with respect to an output parameter. In response to a drive signal, the plurality of optical devices are further configured to adjust the corresponding optical lights with respect to the output parameter while substantially maintaining the predefined nonequivalent relationship.

Array comprising a plurality of adjustable optical devices

An optical wavelength monitor photodiode integrated on a wafer and/or an optical device and coupled to optical components thereof provides wavelength measurement. The optical wavelength monitor includes a photodiode configured to output a signal that is representative of a wavelength of the light. An additional photodiode may be included in the optical wavelength monitor, each photodiode differing from the other in operating characteristics. The monitor may be used in testing the optical device while in wafer form and when the optical device has been cleaved from the wafer at the bar level. Testing/monitoring of the optical device may also be performed during use, for example, to control the wavelength of a laser such as a tunable laser.

Integrated photodiode wavelength monitor

A Bragg grating has a local reflection strength which varies with position along the length of the grating so as to generate a non-uniform wavelength reflection spectrum, enabling compensation for a non-uniform gain profile of the gain section of a tunable laser. In another aspect, a Bragg comb grating is modulated by an envelope function which can also compensate for a non-uniform gain profile. The comb grating may be a phase change grating, with the envelope function shape being controlled by the length between phase changes and/or size of the phase changes.

Bragg grating structure

The present invention concerns tunable distributed Bragg reflector (DBR) semiconductor lasers, in particular a DBR laser with a branched optical waveguidewithin which a plurality of differently shaped lasing cavities may be formed, and a method of operation of such a laser. The laser may comprise a phase control section (), gain section (), a sampled grating DBR () giving a comb-line spectrum and two tunable, chirped DBRs () for broadband frequency training and a coupling section ().

Tunable laser

A Bragg reflector grating comprises a plurality of chirped grating sections (-), in which at least a first chirped grating section and a second chirped grating section have differing ranges of grating pitches. The combined range of grating pitches provided by the first and second chirped grating sections includes at least one discontinuity, such that the first and second chirped grating sections have one or more grating pitches in common and/or there are one or more ranges of grating pitches within the combined range of grating pitches that are absent.

Bragg reflector grating

A tunable laser comprises a gain section and two or more reflectors. At least one of the reflectors is a Bragg grating comprising a reduced strength section comprising a base order periodic pattern of marks and spaces from at which at least some of the marks or spaces are missing. This enables the reflective strength of the grating to be controlled relative to the other reflector. The Bragg grating may be a phase change grating with individual sections being reduced in strength by line removal.

Bragg grating reflection strength control

An apodised Bragg grating comprises a base grating section formed by a base order 5 periodic pattern of marks and spaces. The Bragg grating further comprises one or more apodised grating sections that are formed by a periodic pattern of marks and spaces, each defined by the base order pattern from which at least some of the marks are missing. The determination of which marks are missing may be performed by combining the base order pattern with a higher order modulation envelope function.

Apodised binary Bragg grating

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Northampton, United Kingdom

Andrew John Ward