Quantum light sources are the core resources for photonics-based quantum information processing.We investigate the spectral engineering of photon triplets generated by third-order spontaneous parametric down-conversio...Quantum light sources are the core resources for photonics-based quantum information processing.We investigate the spectral engineering of photon triplets generated by third-order spontaneous parametric down-conversion in micro/nanofiber.The phase mismatching at one-third pump frequency gives rise to non-degenerate photon triplets,the joint spectral intensity of which has an elliptical locus with a fixed eccentricity of√6/3.Therefore,we propose a frequency-division scheme to separate non-degenerate photon triplets into three channels with high heralding efficiency for the first time.Choosing an appropriate pump wavelength can compensate for the fabrication errors of micro/nanofiber and also generate narrowband,non-degenerate photon triplet sources with a high signal-to-noise ratio.Furthermore,the long-period micro/nanofiber grating introduces a new controllable degree of freedom to tailor phase matching,resulting from the periodic oscillation of dispersion.In this scheme,the wavelength of photon triplets can be flexibly tuned using quasi-phase matching.We study the generation of photon triplets from this novel perspective of spectrum engineering,and we believe that this work will accelerate the practical implementation of photon triplets in quantum information processing.展开更多
Spectrally uncorrelated biphotons are the essential resources for achieving various quantum information processing protocols.We theoretically investigate the generation of spectrally uncorrelated biphotons emitted by ...Spectrally uncorrelated biphotons are the essential resources for achieving various quantum information processing protocols.We theoretically investigate the generation of spectrally uncorrelated biphotons emitted by spontaneous fourwave mixing from a fiber nonlinear interferometer which consists of an N-stage nonlinear gain fiber and an(N-1)-stage dispersion modulation fiber.The output biphoton states of nonlinear interference are the coherent superposition of various biphoton states born in each nonlinear fiber,and thus the interference fringe will reshape the biphoton joint spectra.As a result,resorting to Taylor expansion to first order for phase mismatching,we theoretically verify that the orientation of phase matching contours will rotate in a specific way with only varying the length of dispersion modulation fiber.The rotation in orientation of phase matching contours may result in spectrally uncorrelated biphotons and even arbitrary correlation biphotons.Further,we choose micro/nanofiber as the nonlinear gain fiber and single-mode communication fiber as dispersion modulation fiber to numerically simulate the generation of spectrally uncorrelated biphotons from spontaneous fourwave mixing.Here,due to significant frequency detuning(hundreds of THz),Raman background noise can be considerably suppressed,even at room temperature,and photons with largely tunable wavelengths can be achieved,indicating a practicability in many quantum fields.A photon mode purity of 97.2%will be theoretically attained without weakening the heralding nature of biphoton sources.We think that this fiber nonlinear interference with the flexibly engineered quantum state can be an excellent practical source for quantum information processing.展开更多
A method to fabricate fiber Bragg grating （FBG） in an optical microfiber （OM） from a conventional photosensitive fiber is proposed in this letter. The cladding of a conventional photosensitive fiber is etched to 1...A method to fabricate fiber Bragg grating （FBG） in an optical microfiber （OM） from a conventional photosensitive fiber is proposed in this letter. The cladding of a conventional photosensitive fiber is etched to 17 pro. The etched fiber is drawn to an OM 6μm in diameter. The photosensitivity of the fabricated OM is effectively reserved. A FBG in the OM （MFBG） is successfully fabricated using a KrF excimer laser at a fluence of 400 mJ/cm2 through a phase mask with a pitch of 1 089.3 nm. The reflectivity of the FBG is approximately 10%, and the 3-dB spectrum bandwidth is 0.13 nm. The concentration of brine is measured by immersing the MFBG in the liquid, and the minimum detectable refractive index variation can reach 7.2×10^-5 at a refractive index value of 1.33.展开更多
Optical microfibers （OMs） are good alternatives in the field of sensing. In this letter, a simple and effective miniature temperature sensor based on OM is proposed and experimentally verified. Using pure water and ...Optical microfibers （OMs） are good alternatives in the field of sensing. In this letter, a simple and effective miniature temperature sensor based on OM is proposed and experimentally verified. Using pure water and fiber coating as the OM clad, an additional loss will occur due to the absorption of outer medium. The temperature of the outer environment can be estimated by monitoring the change in additional loss. In the demonstrated experiments, a series of OM with different diameters, waist lengths, and constructions are used as sensing elements. The correlation coefficients between the experimental results and the linear fittings are better than 0.99, and the temperature sensitivity obtained by the linear fittings can achieve -0.151 dB/℃ （in pure water） and -0.405 dB/℃ （covered by fiber coating）. Moreover, higher sensitivity can be obtained by decreasing the diameter, increasing the waist length of the OM, or choosing the proper operating wavelength.展开更多
The backscattering characteristics of optical microfiber （OM） are experimentally studied by controlling heating temperature and cooling method during the OM fabrication process. OM samples with various reflectances ...The backscattering characteristics of optical microfiber （OM） are experimentally studied by controlling heating temperature and cooling method during the OM fabrication process. OM samples with various reflectances from 0.1% to 1% are achieved. An OM with waist length of 5 mm, waist diameter of 1 μm, and approximately 0.5% reflectance is used as the end reflector of a fiber Fabry-Perol （F-P） interferometer. A piezoelectric ceramic transducer （PZT） fiber phase modulator is used to test the sensing performance of the fiber F-P interferometer. Experimental results verify that the OM with low reflectance can be used as a reflector in the F-P interferometer.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.61605249)the Science and Technology Key Project of Henan Province of China(Grant Nos.182102210577 and 232102211086).
文摘Quantum light sources are the core resources for photonics-based quantum information processing.We investigate the spectral engineering of photon triplets generated by third-order spontaneous parametric down-conversion in micro/nanofiber.The phase mismatching at one-third pump frequency gives rise to non-degenerate photon triplets,the joint spectral intensity of which has an elliptical locus with a fixed eccentricity of√6/3.Therefore,we propose a frequency-division scheme to separate non-degenerate photon triplets into three channels with high heralding efficiency for the first time.Choosing an appropriate pump wavelength can compensate for the fabrication errors of micro/nanofiber and also generate narrowband,non-degenerate photon triplet sources with a high signal-to-noise ratio.Furthermore,the long-period micro/nanofiber grating introduces a new controllable degree of freedom to tailor phase matching,resulting from the periodic oscillation of dispersion.In this scheme,the wavelength of photon triplets can be flexibly tuned using quasi-phase matching.We study the generation of photon triplets from this novel perspective of spectrum engineering,and we believe that this work will accelerate the practical implementation of photon triplets in quantum information processing.
基金Project supported by the Science and Technology Key Project of Henan Province,China(Grant No.182102210577)the National Natural Science Foundation of China(Grant No.61605249)。
文摘Spectrally uncorrelated biphotons are the essential resources for achieving various quantum information processing protocols.We theoretically investigate the generation of spectrally uncorrelated biphotons emitted by spontaneous fourwave mixing from a fiber nonlinear interferometer which consists of an N-stage nonlinear gain fiber and an(N-1)-stage dispersion modulation fiber.The output biphoton states of nonlinear interference are the coherent superposition of various biphoton states born in each nonlinear fiber,and thus the interference fringe will reshape the biphoton joint spectra.As a result,resorting to Taylor expansion to first order for phase mismatching,we theoretically verify that the orientation of phase matching contours will rotate in a specific way with only varying the length of dispersion modulation fiber.The rotation in orientation of phase matching contours may result in spectrally uncorrelated biphotons and even arbitrary correlation biphotons.Further,we choose micro/nanofiber as the nonlinear gain fiber and single-mode communication fiber as dispersion modulation fiber to numerically simulate the generation of spectrally uncorrelated biphotons from spontaneous fourwave mixing.Here,due to significant frequency detuning(hundreds of THz),Raman background noise can be considerably suppressed,even at room temperature,and photons with largely tunable wavelengths can be achieved,indicating a practicability in many quantum fields.A photon mode purity of 97.2%will be theoretically attained without weakening the heralding nature of biphoton sources.We think that this fiber nonlinear interference with the flexibly engineered quantum state can be an excellent practical source for quantum information processing.
文摘A method to fabricate fiber Bragg grating （FBG） in an optical microfiber （OM） from a conventional photosensitive fiber is proposed in this letter. The cladding of a conventional photosensitive fiber is etched to 17 pro. The etched fiber is drawn to an OM 6μm in diameter. The photosensitivity of the fabricated OM is effectively reserved. A FBG in the OM （MFBG） is successfully fabricated using a KrF excimer laser at a fluence of 400 mJ/cm2 through a phase mask with a pitch of 1 089.3 nm. The reflectivity of the FBG is approximately 10%, and the 3-dB spectrum bandwidth is 0.13 nm. The concentration of brine is measured by immersing the MFBG in the liquid, and the minimum detectable refractive index variation can reach 7.2×10^-5 at a refractive index value of 1.33.
文摘Optical microfibers （OMs） are good alternatives in the field of sensing. In this letter, a simple and effective miniature temperature sensor based on OM is proposed and experimentally verified. Using pure water and fiber coating as the OM clad, an additional loss will occur due to the absorption of outer medium. The temperature of the outer environment can be estimated by monitoring the change in additional loss. In the demonstrated experiments, a series of OM with different diameters, waist lengths, and constructions are used as sensing elements. The correlation coefficients between the experimental results and the linear fittings are better than 0.99, and the temperature sensitivity obtained by the linear fittings can achieve -0.151 dB/℃ （in pure water） and -0.405 dB/℃ （covered by fiber coating）. Moreover, higher sensitivity can be obtained by decreasing the diameter, increasing the waist length of the OM, or choosing the proper operating wavelength.
文摘The backscattering characteristics of optical microfiber （OM） are experimentally studied by controlling heating temperature and cooling method during the OM fabrication process. OM samples with various reflectances from 0.1% to 1% are achieved. An OM with waist length of 5 mm, waist diameter of 1 μm, and approximately 0.5% reflectance is used as the end reflector of a fiber Fabry-Perol （F-P） interferometer. A piezoelectric ceramic transducer （PZT） fiber phase modulator is used to test the sensing performance of the fiber F-P interferometer. Experimental results verify that the OM with low reflectance can be used as a reflector in the F-P interferometer.
