Single-photon stimulated four wave mixing (StFWM) processes have great potential for photonic quantum information processing, compatible with optical communication technologies and integrated optoelectronics. In this paper, we demonstrate single-photon StFWM process in a piece of optical fiber, with seeded photons generated by spontaneous four wave mixing process (SpFWM). The effect of the single-photon StFWM is confirmed by time-resolved four-photon coincidence measurement and variation of four-photon coincidence counts under different seed-pump delays. According to the experiment results, the potential performance of quantum cloning machine based on the process is analyzed.
Single-photon stimulated four wave mixing (StFWM) processes have great potential for photonic quantum information processing, compatible with optical communication technologies and integrated optoelectronics. In this paper, we demonstrate single-photon StFWM process in a piece of optical fiber, with seeded photons generated by spontaneous four wave mixing process (SpFWM). The effect of the single-photon StFWM is confirmed by time-resolved four-photon coincidence measurement and variation of four-photon coincidence counts under different seed-pump delays. According to the experiment results, the potential performance of quantum cloning machine based on the process is analyzed.
Single-photon stimulated four-wave mixing (StFWM) is an important nonlinear optical phenomenon at the single-photon level. In this process, signal and idler photons are stimulated by seeded single photons when two pump photons are annihilated. The generated photons are correlated with each other, and more importantly, one of them is in the same mode with the seeded photons. Hence, StFWM has great potential to realize complex functions of photonic quantum information processing, such as quantum state manipulation and quantum cloning. In this paper, we provide the first experimental demonstration of single-photon StFWM in a piece of optical fiber. By using heralded single photons as the seeded photons, a true single-photon StFWM process is realized at the telecom band. It is confirmed by time-resolved four-photon coincidence measurement and variation of four-photon coincidence counts under different seed–pump delays. According to the experiment results, the potential performance of a quantum cloning machine based on this process is estimated.
Quantum correlations, where two or more parties exhibit strong correlations in a particular degree of freedom are important resources for fundamental science [1], such as the exploration of non-locality and entanglement, as well as non-classical technologies including quantum computation, quantum key distribution and quantum metrology. One typical way to generate correlated photon pairs is to use the spontaneous four-wave mixing process, with demonstrations on various platforms [2]. So far, single-photon stimulated four-wave mixing (FWM) has been demonstrated in optical fibers [3]. Here we show induced correlation by single photon seeded FWM through exploiting the orthogonal polarization modes in an integrated ring resonator [4]. We allow two different four-wave mixing processes to occur simultaneously with the same signal frequency mode but different idler frequency modes (see Fig.1(a)). The single-photon induced FWM process, named here seeded FWM, was created through the link of type-0 SFWM and type-2 SFWM. In the type-0 process, two excitation photons from the same field are converted into two new photons, signal and idler, with the same polarization as the pump field. While in the type-2 FWM, two annihilated photons, each one from a different polarized pump field, namely TE and TM, generate an orthogonal-polarized photon pair. More importantly, spatial and temporal overlapping of two processes and their sharing of one common resonance lead to correlation between the other two signal photons, one from each process. For example, an idler photon created in type-0 FWM seeds the type-2 FWM process or vice versa, i.e. the TM idler photon in Fig. 1, induces correlation between the signal TM and TE photons. This is proven by the observation of a clear coincidence peak for both signal photons in Fig.1(b). Furthermore, we confirmed our observation via power-dependent correlation measurements (see Fig.1 (c)). We summarized the true coincidence count (C) and its coincidence to accidental ratio (CAR) when only the TE pump power is increased while maintaining the TM mode pump power (black squares), and both pump powers are increased with a constant ratio (blue dots). We found that the seeded FWM scales with the square of both pump powers (C ∝ PjePtm) and that the CAR reach its maxima of 1.5 at the available pump power, indicating thermal statistics. Our findings are relevant to the fundamental understanding of spontaneous parametric effects as well as single-photon induced processes and single photon cloning.
Summary form only given. The rapid development of quantum information technology requires the ability to reliably create and distribute single photons [1]. Photon-pair production through spontaneous four-wave mixing (SpFWM) allows heralded single photons to be generated at communication wavelengths and in fiber, compatible with conventional communication systems, with small losses. Creating single photons in desired quantum states require careful design of waveguide structures. This is greatly facilitated by a general numerical approach as presented here. Additionally, such a numerical approach allows detailed analysis of real systems where all relevent effects are included.
Single photon sources are a key element for quantum computing, quantum key distribution (QKD) and quantum communications. In particular, producing single photons at telecommunications wavelengths is valuable for QKD protocols and would enable realizing the quantum internet. The preferred method for their generation has long been spontaneous down conversion in bulk crystals, which suffers from connection loss to fiber networks. In-fiber spontaneous four-wave mixing provides a viable alternative as a photon pair source due to being compatible with existing fiber networks. We present an all-fiber photon pair source based on degenerate four-wave mixing in a 400 m Highly-Nonlinear fiber, with signal and idler wavelengths generated at 1552.5 nm and 1557 nm respectively. The source consists of CW pump laser operating at 1554.75 nm, which is slightly detuned from the zero group velocity dispersion wavelength into the normal dispersion regime. After pair generation in the highly-nonlinear fiber, three arrayed waveguide gratings are employed to spatially separate signal and idler, and provides a 120 dB pump power reduction. Firstly the source is modelled and experimentally characterized in the well known classical regime of stimulated four-wave mixing. The effect of fiber cooling on spontaneous Raman scattering is modelled and characterized, and a 30% reduction in spontaneous emission is found when cooling the fiber to -77°C. In the low power regime the coincidence to accidental count ratio is simulated and measured. An increase in the coincidence to accidental count ratio is observed when cooling the fiber.
Quantum entanglement has been an extremely active field of research, both theoretically and experimentally. Studies on entanglement are fundamental to improving our basic understanding of quantum mechanics. As our understanding of the phenomenon grows, so does interest in using it to advance various technological fields: communications, computing, and sensing, to name just a few. It is now known that entangled photon pairs can be generated through a process known as Spontaneous Four-Wave Mixing (SFWM). In this paper, we report the generation of entangled photon pairs in time intervals by spontaneous four-wave mixing in a nonlinear fiber optic ring resonator. The requirements for efficient SFWM are quite similar to those for classical FWM, but they require even greater precision, especially for quantum applications. To achieve a measurable pair generation rate, a high-intensity pump laser is essential. The nonlinear medium must have high nonlinearity and confinement. This technique is compatible with contemporary fiber, enabling compact, low-cost, and scalable implementations such as quantum memories.
Energy-time entangled photon-pairs at telecom band are generated via spontaneous four wave mixing (SFWM) process in optical fibers under continuous wave (CW) pumping. A time domain filter is used to suppress the impact of noise photons and improve the noise property. The characterization of energy-time entanglement is presented through an experiment of Franson-type interference and a violation of CHSH-Bell inequality. It shows that the SFWM in optical fibers under CW pumping provides a simple and practical way to generate high-quality energy-time entangled photon-pairs at telecom band.