Simple performance evaluation of pulsed spontaneous parametric down-conversion sources for quantum communications

Abstract

Fast characterization of pulsed spontaneous parametric down conversion (SPDC) sources is important for applications in quantum information processing and communications. We propose a simple method to perform this task, which only requires measuring the counts on the two output channels and the coincidences between them, as well as modeling the filter used to reduce the source bandwidth. The proposed method is experimentally tested and used for a complete evaluation of SPDC sources (pair emission probability, total losses, and fidelity) of various bandwidths. This method can find applications in the setting up of SPDC sources and in the continuous verification of the quality of quantum communication links.

Optimal photon-pair single-mode coupling in narrow-band spontaneous parametric downconversion with arbitrary pump profile

“…The heralding ratio Γ 2|1 can hence be determined from the measurements of counts and coincidences, provided the insertion losses have been previously determined [48]. It is then possible to validate its dependence with respect to the pump focusing parameter ξ and the normalized target mode waist α.…”

“…The heralding ratio Γ 2|1 can hence be determined from the measurements of counts and coincidences, provided the insertion losses have been previously determined [48].…”

Conditional Frequency-Domain Beamsplitters Using Phase Modulators

“…For in the microwave range (10-40 GHz), frequency bins with bandwidths Á! in the gigahertz range are thus necessary, for which several filtering techniques can be employed (see [30] and [31]). In Fig.…”

Dual-pump approach to photon-pair generation: demonstration of enhanced characterization and engineering capabilities

“…Important figures of merit include the pair-generation probability and the collection efficiency, which determine bit rates and signal-to-noise ratio, and false detections, which degrade the quality of the photon-pair source. Despite the importance of these parameters, in many sources noise contributions prohibit their direct assessment, and to date such photon-pair source characteristics have been calculated by neglecting noise or assuming pump-independent noise contributions [4], indirect measurements of various source performances [5][6][7], or from fits to multiple measured data points [8][9][10]. Another figure of merit that is critical for protocols and gates that rely on interference of photons from separate sources is the degree of quantum state purity of the individual photons.…”