10 May 2013 Back-to-back issues of Optics Express

Violation of a Bell's inequality with polarization-entangled photons generated in a semiconductor waveguide

Two ICFO papers describe novel experimental set-ups for the generation of polarization-entangled photons. ICFO appears in consecutive issues of Optics Express, representing work that is both novel and of experimental relevance. Research groups led by Professors Morgan Mitchell, Valerio Pruneri and Juan P. Torres are responsible for this back to back appearance.

In the first paper, entitled ‘Generation of polarization-entangled photon pairs in a Bragg reflection waveguide’, researchers in the group led by Prof. Juan P. Torres experimentally demonstrated the generation of polarization-entangled paired photons in a semiconductor Bragg reflection waveguide (BRW), by showing the violation of a Bell\'s inequality. It is important to note that semiconductor platforms offer a unique possibility for building robust high-efficient and easy-to-use out-the-lab generators of quantum light. This work was carried out in collaboration with the University of Toronto.

The second paper, entitled ‘Phase-stable source of polarization-entangled photons in a linear double-pass configuration’, demonstrates a compact, robust, and highly efficient source of polarization-entangled photons in a novel ‘folded sandwich’ configuration, achieving an equivalent unprecedented detection rate of 1.1 million pairs per milliwatt of pump power, while maintaining a very high two-photon entanglement quality. This work, led by the group of Professor Valerio Pruneri, involved also profs. Morgan Mitchell and Juan P. Torres, in collaboration with other European research groups.