News Article

NTT Laser Senses Carbon Monoxide

A boundary-pushing 2.3 micron laser from the Japanese telecoms firm's photonics division looks set to enter production for use in residential CO alarms.

Researchers from NTT Photonics Laboratories have made an InP-based continuous-wave laser that they say emits at the longest ever wavelength reported for such a device.

The laser, described in Electronics Letters on October 11, emits 2.33 µm infra-red light from three 5 nm InAs quantum wells sandwiched between four 5 nm-thick In0.53Ga0.47As barriers.

“This laser will be useful as a light source for CO sensing because its wavelength agrees well with the CO absorption line," say the authors.

The Japanese company is now looking to deploy the laser in commercial detectors that sense CO before the gas reaches lethal concentrations, according to a report on Nikkei.net.

Nikkei.net says that NTT s sensors should be able to detect CO concentrations down to 10 parts per million, whereas the permissable exposure limit for CO is 50 parts per million.

For InAs multi-quantum well (MQW) lasers fabricated on InP substrates, attaining wavelengths longer than 2 µm is difficult because the two materials are lattice mismatched by about 3.2 percent. This makes it difficult to grow the thicker InAs layers that allow longer wavelength lasing.

To make the new laser, the NTT group initially grew a 100 nm-thick InGaAsP guide layer on top of the substrate. This helps to contain the emitted light in a separate confinement heterostructure (SCH) laser design.

This layer and the first InGaAs barrier "“ immediately above "“ were both grown by MOVPE at 500°C. After this the researchers grew the InAs quantum wells at 620°C.

When the MQW structure was finished, a second 100 nm InGaAsP layer completed the SCH design, and finally a p-InP layer was deposited to make the laser essentially symmetrical. The reported device operates with threshold current and threshold current density of 560 mA and 1.56 kA/cm2 respectively.

NTT Electronics has already started shipping sample lasers to equipment manufacturers but prototypes cost thousands of dollars, Nikkei.net says. This report also says that NTT is confident that volume manufacturing will ultimately bring prices down enough to see its lasers used in residential alarms.

CS International to return to Brussels – bigger and better than ever!


The leading global compound semiconductor conference and exhibition will once again bring together key players from across the value chain for two-days of strategic technical sessions, dynamic talks and unrivalled networking opportunities.


Join us face-to-face between 28th – 29th June 2022

  • View the agenda.
  • 3 for the price of 1. Register your place and gain complementary access to TWO FURTHER industry leading conferences: PIC International and SSI International.
  • Email info@csinternational.net  or call +44 (0)24 7671 8970 for more details.

*90% of exhibition space has gone - book your booth before it’s too late!

Register


×
Search the news archive

To close this popup you can press escape or click the close icon.
×
Logo
×
Register - Step 1

You may choose to subscribe to the Compound Semiconductor Magazine, the Compound Semiconductor Newsletter, or both. You may also request additional information if required, before submitting your application.


Please subscribe me to:

 

You chose the industry type of "Other"

Please enter the industry that you work in:
Please enter the industry that you work in:
 
Live Event