Lumentum Technology UK Limited

Selina Farwell

Samuel Davies

Mark Kearley

A method of equalising optical losses, at a required operating wavelength, in waveguide sections in an optoelectronic device comprising a first semiconductor waveguide section and a second semiconductor waveguide section, the method comprising determining () a first optical loss through the first waveguide section for a signal with the required operating wavelength, determining () a second optical loss through the second waveguide section for the signal, determining () a loss difference between the first optical loss and the second optical loss, determining () a first bias voltage based on the loss difference and the operating wavelength, such that the loss difference is reduced, and applying () the bias voltage to the first waveguide section.

Balancing losses in semiconductor optical waveguides

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

A waveguide structure including a waveguide having a thermally controllable section, and a method of manufacturing the structure. The waveguide structure comprises a plurality of layers. The layers comprise, in order: a substrate (), a sacrificial layer (), a lower cladding layer (), a waveguide core layer (), and an upper cladding layer (). The lower cladding layer, waveguide core layer, and upper cladding layer form the waveguide, the waveguide has a waveguide core. The waveguide structure has a continuous via () passing through the upper cladding layer, waveguide core layer, and lower cladding layer and running parallel to the waveguide ridge () along substantially the whole length of the thermally controllable section. The waveguide structure also has a thermally insulating region () in the sacrificial layer extending at least from the via to beyond the waveguide ridge along the whole length of the thermally controllable section. The sacrificial layer comprises a sacrificial material outside of the thermally insulating region, and a thermally insulating gap () or thermally insulating material separating the lower cladding layer and substrate inside the thermally insulating region. The structure is manufactured by providing a wet etch to the sacrificial layer through the via in order to remove material from at least the thermally insulating region.

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Northamptonshire, United Kingdom

Selina Farwell