Photonics Research, Volume. 10, Issue 6, 1417(2022)
Spectrally multiplexed indistinguishable single-photon generation at telecom-band Editors' Pick
Fig. 1. Principles of chip-scale LNOI-based spectrally multiplexed HSPS. (a) A view of future chip-scale LNOI-based spectrally multiplexed HSPS, in which all basic components are integrated on an LNOI photonic chip including pump laser module, (I) photon-pairs generation module, (II) filtering and detecting module, and (III) feed-forward and frequency shifting module. (b) Energy conservation graph of SHG and SPDC. (c) Illustration of multiplexing in frequency domain. Photon-pairs generation module (I) generates broadband correlated signal and idler photons through cascaded SHG and SPDC processes. Idler photons are filtered into different spectral modes and detected by SNSPDs in the filtering and detecting module (II). Detection signals are sent to the logic circuit. The logic circuit sends frequency shifting signal to the feed-forward and frequency shifting module (III), where signal photons are shifted into the common spectral mode. LNOI, lithium niobate on insulator; PPLN, periodically poled lithium niobate; LN, lithium niobate; EOM, electro-optic phase modulator; SNSPD, superconducting nanowire single-photon detector; Freq. Shif. Sig., frequency shifting signals; SHG, second-order harmonics generation; SPDC, spontaneous parametric downconversion.
Fig. 2. Experimental setup for spectrally multiplexed HSPS. PPLN, periodically poled lithium niobate; DWDM, dense wavelength-divided multiplexer; EOM, electro-optic phase modulator; TNF, tunable narrowband filter; BS, beam splitter; PC, polarization controller; TDC, time-to-digit convertor; SNSPD, superconducting nanowire single-photon detector.
Fig. 3. Coincidence count rates without and with frequency shifting. (a) and (b) are the measured coincidence count rates among three individual spectral modes without and with spectral multiplexing, respectively, under the CW pumping power of 4 mW. The horizontal axis corresponds to the relative frequency difference with respect to
Fig. 4. Experimental results from multiplexing of three spectral modes. Blue diamonds are multiplexed source, and red rectangles, orange circles, and yellow triangles represent individual spectral modes of
Fig. 5. Joint spectrum intensity (JSI) between heralding and signal photons in the
Fig. 6. HOM interference between the multiplexed source and the weak coherence source. Red circles are twofold coincidences measured without the heralding procedure. Blue diamonds are threefold coincidences measured under the condition by the heralding procedure without subtracting the contribution of the multiphoton event. Both twofold and threefold coincidences are fitted by Gaussian functions with red and blue curves and have the visibility of
Fig. 7. (a) Experimental setup for generation of frequency shifting signals. AWG, arbitrary waveform generator; Amp., microwave amplifier. (b) Typical electronic signal for frequency shifting. (c) Enhancement of the multiplexed source versus heralding rate. Inset: Heralding efficiency of the multiplexed source versus pump power. Green circles and blue diamonds are measured data while green and blue dashed curves are the result of theoretical calculation. Error bars are estimated using Poisson statistics.
Fig. 8. Threefold coincidences before (green diamonds) and after (blue diamonds) correction. Error bars are estimated using Poisson statistics.
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Hao Yu, Chenzhi Yuan, Ruiming Zhang, Zichang Zhang, Hao Li, You Wang, Guangwei Deng, Lixing You, Haizhi Song, Zhiming Wang, Guang-Can Guo, Qiang Zhou, "Spectrally multiplexed indistinguishable single-photon generation at telecom-band," Photonics Res. 10, 1417 (2022)
Category: Quantum Optics
Received: Dec. 15, 2021
Accepted: Apr. 2, 2022
Published Online: May. 20, 2022
The Author Email: Qiang Zhou (zhouqiang@uestc.edu.cn)