Dublin City University

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

Liam Barry

Prince Anandarajah

John Hegarty

James Christopher O'Gorman

Sylwester Latkowski

Herve Armel Francois Folliot

Slywester Latkowski

The present application provides an optical comb source in which the comb is produced by seeding a gain switched Fabry-P&#xe9;rot laser with light from a single mode laser, while at the same time driving the Fabry-P&#xe9;rot laser with a DC bias and RF signal.

Wavelength tunable comb source

The present application relates to comb frequency generator devices generally and more particularly to the use of comb generators for use in fibre optic communications. More particularly, the application provides a frequency comb generator device. The device comprises a laser (), a biasing circuit for providing a DC bias current (), an RF circuit () providing a RF signal and a drive circuit () for combining the RF signal with the DC bias current to provide a drive current to the laser (). With the DC bias current below threshold of the laser diode and RF bias with a frequence close to the relaxation ascillation frequency of the laser diode, a periodic pulse train is emitted with constant phase.

Optical wavelength comb generator device

A semiconductor photodetector () for detecting short duration laser light pulses of predetermined wavelength in a light signal () comprises a micro-resonator () of vertical Fabry-Perot construction having a Bragg mirror pair, namely, a front mirror () and a rear mirror () with an active region () located between the front and rear mirrors (). An N-type substrate () supports the rear mirror (). The light signal () is directed into the active region () through the front mirror () while a pump beam () is directed into the active region () at an end () thereof. The spacing between the front and rear mirrors () is such as to cause light of the predetermined wavelength to resonate between the mirrors (). The semiconductor material of the active region () is selected so that one photon from each of the light signal () and the pump beam () are required to transfer one electron from a valence band () of the active region () across a bandgap () to a conduction band () so that the active region operates on the principle of Two-Photon Absorption. On the active region () being simultaneously subjected to the pump beam and light of the predetermined wavelength in the light signal () electrons are transferred by Two-Photon Absorption from the valence band () to the conduction band (), thus causing a change in the voltage developed across the active region (). The change in voltage is detected between an electrode () on the substrate () and electrodes () on the front mirror () thereby indicating the presence of light of the predetermined wavelength in the light signal ().

Semiconductor photodetector

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Dublin, Ireland

Liam Barry