Single photon source based on active time multiplexing

IGNACIO HERNÁN LÓPEZ GRANDE; AGUSTINA GABRIELA MAGNONI; MIGUEL ANTONIO LAROTONDA; KNOLL, L.T.

Otro; VII Paraty Quantum Information School and Workshop; 2019

We present the work in progress of a synchronized photon source in the telecom range, based on the process of Spontaneous Parametric Downconversion (SPDC) in a periodically poled KTP nonlinear crystal (PPKTP). This device has two main components: a source of correlated photon pairs and a time multiplexing system that synchronizes one of the photons with a clock tick, using temporal information from the herald photon. The first component is already implemented and characterized: a 532 nm single mode laser (1 MHz bandwidth) pumps the nonlinear crystal. Correlated photons are generated at 1550 nm ("signal") and at 810 nm ("idler") by SPDC. The idler photon is used as a herald. We have studied the performance of the system for different pump powers, measuring single counts at the idler beam, coincidences and the coincidence-to-accidental ratio (CAR). Also, we characterized coupling and heralding efficiencies (obtaining an 11%). The output spectra was measured for different crystal temperatures.We are currently working on the experimental implementation of the time multiplexing system. The aim is to synchronize the 1550 nm photon arrival with an external clock tick, in order to obtain a deterministic single photon source. This approach consists in using the timing information in the detection of the idler photon to modify the signal's path so that it exits the system at an specific time. The path modification will be done by a series of fast optical switches connected to a binary division fiber network. We will present a detailed theoretical analysis and a simulation of the source statistics including losses and non-ideal components.