Generation of photon pairs in dispersion shift fibers through spontaneous four wave mixing: Influence of self-phase modulation

Abstract

Correlated signal and idler photon pairs with small detuning in the telecom band can be generated through spontaneous four-wave mixing in dispersion shift fibers. However, photons originated from other nonlinear processes in optical fibers, such as Raman scattering and self-phase modulation, may contaminate the photon pairs. It has been proved that photons produced by Raman scattering are the background noise of photon pairs. Here we show that photons induced by self-phase modulation of pump pulses are another origin of background noise. After studying the dependence of selfphase modulation induced photons in signal and idler bands, we demonstrate that the quantum correlation of photon pairs can be degraded by the selfphase modulation effect. The investigations are useful for characterizing and optimizing an all fiber source of photon pairs.

Characterizing the noise output by a fiber-based entangled photon source

“…A thorough investigation of the SPM rate in fiber-based entangled photon pair sources and the dependence on power and detuning can be found in Ref. 5. Here, we replaced the photon generation rates (µ, r i , s i ) in Eqs.…”

“…4 Furthermore, spectral broadening of the pump due to self-phase modulation (SPM) can also result in significant noise output in the entangled photon band. 5 In this paper, we show that, by fitting parameters accessible with only direct detection to a theoretical model that includes nonlinear effects, a FWM-based entangled photon pair source can be fully characterized by measuring the singles and coincidence counting rates when varying the pump power. In particular, we determined the average number of polarization-entangled photon pairs generated by FWM and the average number of noise photons generated by Raman scattering and SPM of the pump as a function of power by fitting the singles and coincidence data with a theoretical model of the photon generation rates.…”