Modeling photon pair generation by second-order surface nonlinearity in silica nanofibers

Abstract

In this paper, we present a design of an all-fiber source of correlated photon pairs based on standard telecommunications tapered fibers. We examine the generation of correlated photon pairs using parametric process (") in silica tapered optical fibers. This nonlinear process is ensured thanks to surface dipole and bulk multipole nonlinearities. The process of photons creation is modeled by taking into account the vector aspect of the propagation of the optical field in a silica nanofiber. The phase matching is provided by propagating the pump field in one spatial mode, while generating a photon pair in another spatial mode. The generation efficiency of photon pairs depends on diameter uniformity of the nanofiber after the manufacturing process. We size this nanofiber for a good optimization of photon pair generation efficiency, we report that the tolerance in diameter uniformity is = 2 nm for a generation rate of photon pairs estimated to $% ≈ 22 000 pairs/s, for 1 W power pump and a nanofiber length of 1.1 mm. Deposits on the nanofiber can be used in order to relax the manufacturing constraints on diameter to maximize the generation rate of photon pairs. As an example, the use of Polytetrafluoroethylene (PTFE) on the nanofiber applied as a cladding whose thickness is infinite makes it possible to relax the constraints on the nanofiber diameter. For the same = 2 nm, a generation rate of photon pairs estimated to $% ≈ 78 000 pairs/s for 1 W power pump and a nanofiber length of 2.4 mm is predicted.

Optical microfiber or nanofiber: a miniature fiber-optic platform for nanophotonics

“…However, when the fiber diameter decreases to the subwavelength scale, the surface dipole and bulk multipole nonlinearities will contribute evidently to the second-order nonlinearity. The theoretical framework of the SHG in MNFs has been well-studied since 2010 [268–270] . For efficient SHG, intermodal phase matching and high mode overlapping are highly desirable.…”

Improving photon pair generation in silica nanofibers through PMMA/DR1 nonlinear coating optimization

“…Here, 𝑔 " ≈ 𝜌 " 𝑎 " (𝜔 % ), where 𝑎(𝜔 % ) represents the square root of the power at the pump frequency 𝜔 % , and Δ𝛽 is the phase mismatch. We assume that 𝜌, which is the efficiency of the sum frequency generation process (i.e., the reverse process of SPDC), is constant over the wavelength range considered [4].…”

Gas-pressure tuning of wavelength of photon pair emitted by Four-Wave-Mixing in Nanofibers

“…Nanofibers are a very interesting system to realize generation of pairs of photons, either using third order nonlinearity using Four Wave Mixing [1,2], or using new second order nonlinear mechanisms allowed by surface nonlinearities brought by the small dimension of the fiber [3]. The nanofiber is pulled with tapers that gives good injection and extraction of pump beam and emitted photons.…”