University College Cork

The Provost Fellows and Scholars of the College of the Holy and Undivided Trinity of Queen Elizabeth, Near Dublin

The Provost, Fellows, Foundation Scholars & the Other Members of Board, of the College of the Holy & Undiv. Trinity of Queen Elizabeth, Near Dublin

Brendan John Roycroft

Paul Martin Lambkin

Brian Corbett

Pleun Maaskant

Wei-Hua Guo

John F Donegan

Richard Phelan

Qiao-Yin Lu

A tunable laser device () comprises integrally formed first and second ridge waveguides (). A longitudinally extending ridge () defines first and second light guiding regions () of the first and second waveguides () A plurality of first and second slots () extending laterally in the ridge () adjacent the first and second waveguides (), produce first and second mirror loss spectra of the respective first and second waveguides () with minimum peak values at respective first and second wavelength values. The spacing between the second slots () is different to that between the first slots () so that with one exception the minimum peak values of the first and second mirror loss spectrum occur at different wavelength values. The first and second waveguides () are independently pumped with variable currents to selectively vary the common wavelength at which the minimum peak values of the first and second mirror loss spectra occur to produce Vernier tuning of the device.

Tunable laser device and a method for producing light of respective selectable wavelengths

An initial epitaxial layer of GaN is grown on a sapphire substrate. The epitaxial layer is then etched in a reactive ion etch (RIE) chamber. This etching acts preferentially at defects, causing them to become enlarged cavities. The cavities are too large in proportion to the crystal lattice to act as defects in the usual sense, and so a further GaN epitaxial layer fills into the cavities. Thus, propagation of defects is avoided.

Defect reduction in semiconductor materials

Growing community of inventors

Youghal, Ireland

Brendan John Roycroft