Optical isolators,the photonic analogs of electronic diodes,are essential for ensuring the unidirectional flow of light in optical systems,thereby mitigating the destabilizing effects of back reflections.Thin-film lit...Optical isolators,the photonic analogs of electronic diodes,are essential for ensuring the unidirectional flow of light in optical systems,thereby mitigating the destabilizing effects of back reflections.Thin-film lithium niobate(TFLN),hailed as“the silicon of photonics,”has emerged as a pivotal material in the realm of chip-scale nonlinear optics,propelling the demand for compact optical isolators.We report a breakthrough in the development of a fully passive,integrated optical isolator on the TFLN platform,leveraging the Kerr effect to achieve an impressive 10.3 dB of isolation with a minimal insertion loss of 1.87 dB.Further theoretical simulations have demonstrated that our design,when applied to a microring resonator with a Q factor of 5×10^(6),can achieve 20 dB of isolation with an input power of merely 8 mW.This advancement underscores the immense potential of lithium niobate-based Kerr-effect isolators in propelling the integration and application of high-performance on-chip lasers,heralding a new era in integrated photonics.展开更多
Yttrium iron garnet （YIG） is widely used for microwave ferrite devices, especially for optical isolators. In this paper, ferrite ceramic target using cerium （Ce）-substituted YIG was made using ferric oxide （Fe203...Yttrium iron garnet （YIG） is widely used for microwave ferrite devices, especially for optical isolators. In this paper, ferrite ceramic target using cerium （Ce）-substituted YIG was made using ferric oxide （Fe203）, cerium oxide （CeO2） and yttrium oxide （Y2O3） powders as raw material. Ce： YIG thin films were fabricated by radio frequency （RF） magnetron sputtering. The experimental result showed that the polycrystalline YIG was obtained after sintering at 1 350 ℃ for 6 h, and the polycrystalline Ce： YIG thin films were achieved annealing up to 700 ℃ in the air.展开更多
We experimentally demonstrate an optical isolator utilizing high-quality-factor whispering gallery modes in a yttrium iron garnet(YIG)microsphere,coupled with an integrated Si_(3)N_(4)waveguide.By applying a magnetic ...We experimentally demonstrate an optical isolator utilizing high-quality-factor whispering gallery modes in a yttrium iron garnet(YIG)microsphere,coupled with an integrated Si_(3)N_(4)waveguide.By applying a magnetic field in the vertical direction of the resonator equator,we achieve the breaking of degeneracy between the clockwise(CW)and counterclockwise(CCW)modes,driven by photonic spin-orbit coupling(SOC)and the Faraday effect.The maximum wavelength separation observed is about 7.9 pm,comparable with the linewidth of the mode.The better effect of the refractive index matching between the YIG microsphere and the Si_(3)N_(4)waveguide enables an isolation ratio of 16.9 dB under the critical coupling condition.This work presents a novel integrated approach for realizing non-reciprocity in photonic circuits,advancing the development of compact high-performance photonic devices.展开更多
A waveguide optical isolator with a CeY2Fe5O12 guiding layer employing a nonreciprocal phase shift was studied. The isolation ratio of more than 12.2 dB was achieved at a wavelength of 1.55μm.
Mediated by the interactions with quantum vacuum fields,a probe laser field propagating in a nonlinear optical medium can generate new pair of light fields over a broad spectral range via spontaneous parametric proces...Mediated by the interactions with quantum vacuum fields,a probe laser field propagating in a nonlinear optical medium can generate new pair of light fields over a broad spectral range via spontaneous parametric process.Such process is inherently independent of the incident direction of light and reciprocal thus far,due to the directionindependent field-vacuum interactions.In this work,we experimentally demonstrate within sodium atomic vapors that such spontaneous parametric process can be nonreciprocal by unidirectionally coupling it to another pumped four-wave mixing process.Thanks to the broad bandwidth of the spontaneous parametric process,in combination with the Doppler and power-induced broadening of atomic energy levels,we achieve optical isolation with isolation ratio>25 dB over a bandwidth larger than 100 GHz.Considering that both spontaneous parametric processes and the pumped four-wave mixing have been realized in diverse solid photonic platforms,the demonstrated concept can motivate further explorations in the design of integrated magnetic-free broadband optical nonreciprocity via the interactions between nonlinear optical processes.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2022YFF0712800 and 2019YFA0308700)。
文摘Optical isolators,the photonic analogs of electronic diodes,are essential for ensuring the unidirectional flow of light in optical systems,thereby mitigating the destabilizing effects of back reflections.Thin-film lithium niobate(TFLN),hailed as“the silicon of photonics,”has emerged as a pivotal material in the realm of chip-scale nonlinear optics,propelling the demand for compact optical isolators.We report a breakthrough in the development of a fully passive,integrated optical isolator on the TFLN platform,leveraging the Kerr effect to achieve an impressive 10.3 dB of isolation with a minimal insertion loss of 1.87 dB.Further theoretical simulations have demonstrated that our design,when applied to a microring resonator with a Q factor of 5×10^(6),can achieve 20 dB of isolation with an input power of merely 8 mW.This advancement underscores the immense potential of lithium niobate-based Kerr-effect isolators in propelling the integration and application of high-performance on-chip lasers,heralding a new era in integrated photonics.
基金National Natural Science Foundation of China(NSFC)(No.51175418)Program for New Century Excellent Talents in University(No.93JXDW02000006)+4 种基金Natural Science Foundation of Shaanxi Province(No.2011JQ7004)Fundamental Research Funds for the Central Universities of Xi'an Jiaotong University(No.2011jdgz09No.2011jdhz23No.xjj2011068)Fund of the State Key Laboratory of Digital Manufacturing Equipment & Technology(No.DMETKF2012009)
文摘Yttrium iron garnet （YIG） is widely used for microwave ferrite devices, especially for optical isolators. In this paper, ferrite ceramic target using cerium （Ce）-substituted YIG was made using ferric oxide （Fe203）, cerium oxide （CeO2） and yttrium oxide （Y2O3） powders as raw material. Ce： YIG thin films were fabricated by radio frequency （RF） magnetron sputtering. The experimental result showed that the polycrystalline YIG was obtained after sintering at 1 350 ℃ for 6 h, and the polycrystalline Ce： YIG thin films were achieved annealing up to 700 ℃ in the air.
基金supported by the National Natural Science Foundation of China(Nos.92250302,11934012,12104442,and 12474394)the Natural Science Foundation of Anhui Province(No.2308085J12)the Fundamental Research Funds for the Central Universities。
文摘We experimentally demonstrate an optical isolator utilizing high-quality-factor whispering gallery modes in a yttrium iron garnet(YIG)microsphere,coupled with an integrated Si_(3)N_(4)waveguide.By applying a magnetic field in the vertical direction of the resonator equator,we achieve the breaking of degeneracy between the clockwise(CW)and counterclockwise(CCW)modes,driven by photonic spin-orbit coupling(SOC)and the Faraday effect.The maximum wavelength separation observed is about 7.9 pm,comparable with the linewidth of the mode.The better effect of the refractive index matching between the YIG microsphere and the Si_(3)N_(4)waveguide enables an isolation ratio of 16.9 dB under the critical coupling condition.This work presents a novel integrated approach for realizing non-reciprocity in photonic circuits,advancing the development of compact high-performance photonic devices.
文摘A waveguide optical isolator with a CeY2Fe5O12 guiding layer employing a nonreciprocal phase shift was studied. The isolation ratio of more than 12.2 dB was achieved at a wavelength of 1.55μm.
基金supported by National Natural Science Foundation of China(Grant Nos.62475209,62022066,12074306 and 92365107)the National Key R&D Program of China(Grant No.2019YFA0308700)+2 种基金Qinchuangyuan“Scientist+Engineer”Team Construction of Shaanxi Province(Grant No.2024QCY-KXJ-178)Key Scientific and Technological Innovation Team of Shaanxi Province(2021TD-56)the Program for Innovative Talents and Teams in Jiangsu(Grant No.JSSCTD202138).
文摘Mediated by the interactions with quantum vacuum fields,a probe laser field propagating in a nonlinear optical medium can generate new pair of light fields over a broad spectral range via spontaneous parametric process.Such process is inherently independent of the incident direction of light and reciprocal thus far,due to the directionindependent field-vacuum interactions.In this work,we experimentally demonstrate within sodium atomic vapors that such spontaneous parametric process can be nonreciprocal by unidirectionally coupling it to another pumped four-wave mixing process.Thanks to the broad bandwidth of the spontaneous parametric process,in combination with the Doppler and power-induced broadening of atomic energy levels,we achieve optical isolation with isolation ratio>25 dB over a bandwidth larger than 100 GHz.Considering that both spontaneous parametric processes and the pumped four-wave mixing have been realized in diverse solid photonic platforms,the demonstrated concept can motivate further explorations in the design of integrated magnetic-free broadband optical nonreciprocity via the interactions between nonlinear optical processes.
