Oclaro Technology Limited

Bookham Technology Limited

Lumentum Operations LLC

Lumentum Technology UK Limited

Robert Anthony Griffin

Stephen K Jones

Karl M Kissa

John M Heaton

Robert Graham Walker

David Glassner

Robert Ian Johnstone

Andrew John Ward

Adrian Perrin Janssen

Brian Lee Heffner

Ian B Betty

Neil David Whitbread

Paul Firth

Lloyd Nicholas Langley

Samuel Davies

Colin Smith

Amyas Daniel Holroyd

Sam Davies

Selina Farwell

Anthony George Foster

Stephen Jones

Ian Brian Betty

A method of operating an optoelectronic device comprising an optical waveguide section, the optical waveguide section comprising a semiconductor core, the method comprising the steps of determining () a range for a negative bias voltage for the waveguide section for which an optical loss of the core is lower than an optical loss at zero bias for an operating wavelength range of the device, selecting () a bias voltage within the range and applying () the selected bias voltage to the waveguide section.

Negative bias to improve phase noise

An electrical-optical modulator may include one or more optical waveguides to propagate one or more optical signals in a direction of propagation. An optical waveguide of the one or more optical waveguides may include a time delay section, a first modulation section preceding the time delay section in the direction of propagation, and a second modulation section following the time delay section in the direction of propagation. The first modulation section and the second modulation section may be configured to be associated with opposite modulation polarities, and the time delay section may be configured to delay a phase of the one more optical signals relative to the first modulation section. The electrical-optical modulator may include one or more signal electrodes to propagate one or more signals in the direction of propagation in order to modulate the one or more optical signals through electrical-optical interaction.

Electrical-optical modulator

An electrical-optical modulator may include a first section configured for a first electrical-optical interaction between one or more optical waveguides and one or more signal electrodes. The electrical-optical modulator may include a second section configured to increase or decrease a relative velocity of signals of the one or more signal electrodes to optical signals of the one or more optical waveguides relative to the first section. The electrical-optical modulator may include a third section configured for a second electrical-optical interaction between the one or more optical waveguides and the one or more signal electrodes according to an opposite modulation polarity relative to the first section.

A Mach-Zehnder modulator for modulating optical signals, and comprising: a plurality of modulating waveguide sections; at least one bias electrode in electrical communication with at least one modulating waveguide section and configured to apply at least one electrical bias signal to one or more of the modulating waveguide sections; and an output optical combiner comprising a plurality of inputs and a plurality of outputs, wherein the plurality of inputs of the combiner are in optical communication with output sides of the plurality of modulating waveguide sections, and wherein a plurality of the outputs of the combiner are monitor outputs.

Dither free bias control

An optical communications apparatus comprising a host () and an optical module () comprising a Mach-Zehnder modulator (), MZM, wherein the optical module is removably connected to the host via a connection path, the optical communications apparatus comprising: a signal generator () at the host, configured to generate a plurality of calibration signals at a plurality of frequencies; a host interface () configured to transmit the calibration signals to the optical module via the connection path; a module interface () configured to receive the transmitted calibration signals; wherein the MZM is configured to use the calibration signals to modulate a laser light source () and biased to a point at which average output power is proportional to the output modulated signal; an optical detector configured to measure an average magnitude of an output of the MZM when each of the calibration signals is used to modulate the laser light source; one of a host calibration unit () and a module calibration unit (), configured to determine a magnitude response of the connection path based on the measured average magnitudes and magnitudes of the respective calibration signals, and further configured to determine a pre-emphasis characteristic based on the magnitude response, the pre-emphasis characteristic for application to signals transmitted by the optical transmitter in use.

Calibration of pluggable optical module

There is described a transmitter device for transmitting an optical signal in the form of a plurality of subcarrier channels having different wavelengths. The device comprises first and second optical carrier emitters for emitting light in first and second subcarriers at first and second frequencies or polarizations respectively. First and second modulators are provided for modulating the first and second subcarriers with first and second modulation signals. An interleaver is provided for interleaving the first and second modulated subcarriers into the optical signal. First and second digital signal processing units are configured to pre-emphasize the first and second modulation signals to compensate for a wavelength-dependent power transfer function of the interleaver.

Electronical compensation of an interleaver transfer function for optical multiple carrier transmission

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.

Monolithically integrated tunable semiconductor laser

Optical devices are disclosed consisting of optical chips (planar lightwave circuits) which have optically symmetric or matching designs and properties and optical components which create asymmetry in the optical devices. The devices find application in detection in coherent and non-coherent optical communications systems.

Optical chips and devices for optical communications

A Mach-Zehnder interferometer (MZI) incorporates a tunable multimode interference (MMI) coupler comprising a tunable MMI coupler with a tuning electrode on a surface of a tunable MMI region and an electrically insulating region provided within the tunable MMI region. The MMI region is tunable in response to detection of a photocurrent by a photodetector section. Such a tunable MZI is particularly advantageous in enabling a split ratio of an optical splitter, the split ratio and the splitter to be controlled in a particularly efficient manner.

Optical waveguide splitters

The present invention provides a method and apparatus for phase aligning two optical signals within an optical transmitter to each other (and, in some embodiments, to a pulse carved optical signal) using integrated complimentary taps and a dither signal. The phase of a first signal may be intentionally offset relative to the phase of a second signal. Based on the offset, a correction factor may be calculated. The correction factor may be used to shift the phase of the first signal and/or the second signal in order to generally align the signals. This procedure may be automatically performed in a feedback loop to cause the signals to come into alignment and maintain the alignment of the signals during operation of the transmitter.

Alignment of a data signal to an alignment signal

A method of transmitting a plurality n data streams comprises modulating an optical carrier using differential M-ary phase shift key (DMPSK) signalling in which M=2. Advantageously the method comprises using differential quaternary phase shift keying in which n=2. A particular advantage of the method of the present invention is that since the data is differentially encoded in the form of phase changes rather than absolute phase values this enables the modulated optical carrier to be demodulated using direct detection without requiring a phase-locked local optical oscillator. The invention is particularly applicable to WDM communication systems.

Optical communications

A method of transmitting a plurality n data streams comprises modulating an optical carrier using differential M-ary phase shift key (DMPSK) signaling in which M=2. Advantageously the method comprises using differential quaternary phase shift keying in which n=2. A particular advantage of the method of the present invention is that since the data is differentially encoded in the form of phase changes rather than absolute phase values this enables the modulated optical carrier to be demodulated using direct detection without requiring a phase-locked local optical oscillator. The invention is particularly applicable to WDM communication systems.

Demodulation of an optical carrier

A modulator arrangement for modulating an optical signal using a differential quadrature phase shift key for use in an optical wavelength division multiplex (WDM) optical communications system comprising a laser for producing an optical signal of a selected wavelength, which signal is split by a splitter (), each part of said split signal being applied to a respective phase modulator (). The phase modulators () are adapted to modulate the phase of the signal in dependence on a respective drive voltage and the phase of the output of at least one modulator is shiftable. The split signals are recombined by an optical recombiner () to form an optical phase shift key output. The arrangement further comprises a phase modulator () adapted to chirp the optical phase shift key output.

Photonic encoder

A method of transmitting a plurality n data streams comprises modulating an optical carrier using differential M-ary phase shift key (DMPSK) signalling in which M=2. Advantageously the method comprises using differential quaternary phase shift keying in which n=2. A particular advantage of the method of the present invention is that since the the data is differentially encoded in the form of phase changes rather than absolute phase values this enables the modulated optical carrier to be demolutated using direct detection without requiring a phase-locked local optical oscillator. The invention is particularly applicable to WDM communication systems.

A modulator arrangement adapted to use a differential quadrature phase shift key for use in an optical wavelength division multiplex (WDM) optical communications system, comprising a precoder (), which is adapted to generate drive voltages for first and second phrase modulators () in dependence upon first and second data streams. The respective drive voltages for the first and second modulators () are fed back to the precoder inputs with a delay related to the line speed of the data system, wherein the length of the delay corresponds to n bits.

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Northants, United Kingdom

Robert Anthony Griffin