Generation of heralded single photons beyond 1100 nm by spontaneous four-wave mixing in a side-stressed femtosecond laser-written waveguide

Abstract

We demonstrate a monolithically integrable heralded photon source in a femtosecond laser direct written glass waveguide. The generation of photon pairs with a wide wavelength separation requires a concomitant large birefringence in the normal dispersion regime. Here, by incorporation of sidestress tracks, we produce a waveguide with a birefringence of 1.64 × 10 −4 and propagation loss as low as 0.21 dB/cm near 980 nm. We measure photon pairs with 300 nm wavelength separation at an internal generation rate exceeding 5.05 × 10 6 /s. The second order correlations indicate that the generated photon pairs are in a strongly non-classical regime.

Parasitic Photon-Pair Suppression via Photonic Stop-Band Engineering

“…2 κ/ [πn SiO2 (1550 nm)] ≈ 1.4 nm centered at both ω Bx and ω By [31]. We note that SFWM has been observed in even shorter pieces of glass [32,33]. The JSI corresponding to the fiber with a grating introduced can be seen in Fig.…”

“…Assuming a grating index contrast of ∆n = 2.1 × 10 −3 and the grating to have the same effect on both polarizations, we calculate that 94,000 periods of length 536 nm (L = 50 mm) can achieve a grating strength of κL ∼ 137 with photonic stop-bands of width ∆λ ≈ (1550 nm) 2 κ/ [πn SiO2 (1550 nm)] ≈ 1.4 nm centered at both ω Bx and ω By [31]. We note that SFWM has been observed in even shorter pieces of glass [32,33]. The JSI corresponding to the fiber with a grating introduced can be seen in Fig.…”

Spectral control of nonclassical light using an integrated thin-film lithium niobate modulator

“…The ability to manipulate photon spectra is a prerequisite to implement frequencydomain protocols and schemes, such as spectral linear optical quantum computing [4], as well as frequency-multiplexed quantum repeaters [5] and quasi-deterministic single-photon sources [6,7]. In addition, different sources of single photons, produced by heralding photon pairs [8,9] or from solid-state emitters [10], vary largely in frequency and bandwidth. Spectral control of single photons is therefore crucial for matching frequency/bandwidth differences and inhomogeneities among these photon sources, and for interfacing them with spectrally mismatched quantum memories and stationary qubits [11][12][13].…”

Generation and manipulation of entangled photons on silicon chips

“…In addition, it is relatively difficult to realize an active device based on nonlinear-optical effect, such as a photon-pair source on a silica chip, because of the small nonlinearity of silica waveguides. Note that there have been several reports of photon-pair generation [29][30][31] using femtosecond laser direct written silica waveguides [32].…”