© Physics Department Ateneo de Manila University
© Physics Department Ateneo de Manila University

Lasers improve communications and sensing applications

The lateral photonic integration of oxide-confined, leaky, vertical-cavity, surface-emitting lasers enables applications in data communications and sensing.

Vertical-cavity, surface-emitting lasers (VCSELs) operate at 850nm and are based on oxide-confined apertures. These are used in optical interconnects in data centres, supercomputers, wireless backbone networks, and consumer applications.

As processor productivity in these applications increases, the continuous improvement of performance and scale transmission speeds also becomes necessary.

Developers have recently begun to generate devices capable of transmitting 40 Gigabits per second (Gb/s) at moderate current densities. The researchers have also demonstrated 54Gb/s non-return-to-zero transmission through 2.2km of multimode fibre.

Now, 108Gb/s per wavelength transmission can be achieved over 100-300m of multimode fibre through advanced modulation formats.

Engineer and lead researcher Nikolay Ledentsov of VI Systems said: “Our approach uses oxide-confined, leaky VCSELs, which – through the application of proper epitaxial design – enable the generation of high optical leakage losses for high-order transverse modes. Using these devices, we extend the single-mode behaviour of the laser toward large oxide aperture diameters.

“With our approach, we aim to create an additional cavity at a wavelength longer than the VCSEL cavity mode.”

The research has proven the possibility to significantly improve VCSEL spectral quality without additional processing steps. The occurrence of in-plane leakage through leakage lobes in the far-field profile of the device has also been confirmed.

This project received funding from the European Union’s Horizon 2020 research and innovation programme. Click here for more information.