Detuning DFB lasers increases fibre optic bandwidth, explained Horacio Cantu at AOP 2017.

22 May 2017

CST Global, the UK’s leading, independent, III-V opto-electronic, semiconductor foundry is pleased to confirm that Research Engineer, Horacio Cantu, was invited to speak at the Applications in Optics and Photonics (AOP) conference in Faro, Portugal, May 2017. Horacio presented his recently published white paper entitled, “Performance characteristics of 1550 nm and 1310 nm detuned, ridge waveguide, distributed feedback, laser diodes” (AO100-194), co-authored by CST Global’s Director of Engineering, Andrew McKee.

The paper acts as an interim summary by CST Global for the iBROW project (Innovative ultra-Broadband Ubiquitous Wireless Communications Through Tera-hertz Transceivers), led by the University of Glasgow. iBROW is a funded, research project looking at the development of new technology platforms for ultra-broadband, communication networks of multiple Gigabits / second – massively out-performing current platforms.

Horacio explains the significance of the white paper to ultra-broadband network development, “We can modulate light with radio-data, for transmission over fibre-optic networks, without analogue to digital conversion. The available bandwidth is huge; there is almost no latency; and the data can remain in its original format, for transmission via passive networks.

“The white paper is concerned with the performance of in-plane, ridge waveguide, DFB laser diodes for data transmission, centred on 1550 nm and 1310 nm wavelengths. We successfully showed that ‘detuning’ DFB lasers from their peak optical gain increases modulation efficiency; a bias power to frequency characteristic proportional to data carrying capacity or bandwidth. We also showed that, as the temperature increases from 25°C to 85°C, modulation efficiency can also be increased.

“Both carrier wavelengths enable an ultra-broadband solution. We found 1310 nm lasers had greater modulation efficiency than 1550 nm lasers. However, because 1550 nm has a much larger transmission range, more research is required to establish if it is the best, practical, ultra-broadband solution in the long-term.

“We are a long way from a commercial, ultra-broadband solution that is low cost, energy-efficient, compact, operates at room temperature and integrates consumer portable devices and fibre-optic networks. However, the white paper concludes that detuning DFB laser transmitters increases bandwidth capacity in optical fibre networks.”