photon detectors for telecommunications wavelengths

Practically speaking, single photon detection has not been something pursued very heavily at the wavelengths used for telecommunication signals. Part of the problem is that performance of single photon detectors are rather constrained at such long wavelengths. But, says Robert Thew, a scientist at the University of Geneva, the time is coming when single photon detectors may be needed in telecommunications.

“Up until now,” Thew tells PhysOrg.com, “classical communication has not done too badly with the detectors available now. But now they are getting pushed to the limit as optical communications explodes. Single photon detectors are becoming more important.”

In order to improve the ability of a single photon detector to work with signals with telecommunications wavelengths (about 1550 nanometers), Thew and his colleagues at the University of Geneva, Zbinden and Gisin, suggest a scheme that involves upconverting these signals using a tunable pump source to a silicon detector. Their work is published in Applied Physics Letters: “Tunable upconversion photon detector.”

“Photon detection in general is a key enabling field of research,” Thew explains. “And it is improving all the time. Photon detection is used for quantum cryptography and computing as well as for metrology and telecommunications. Our experiment is one that shows how telecom wavelength photons can be converted into the regime of silicon detectors.”

Source: http://www.physorg.com/news139226533.html