Single photon source based on active time multiplexing

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

Otro; Giambiagi Winter School; 2019

Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires

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 multiplexingsystem 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. Correlatedphotons 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 thesystem for different pump powers, measuring single counts at the idler beam, coincidences and the coincidence-to-accidental ratio (CAR). Also, wecharacterized 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 anexternal clock tick, in order to obtain a deterministic single photon source. This approach consists in using the timing information in the detection of the idlerphoton 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 switchesconnected 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.