Birefringence(polarization-related phase-shift),polarization dependent gain(PDG) and mode coupling are three factors that may synchronously influence the transmission of single-wavelength polarized light in optical fi...Birefringence(polarization-related phase-shift),polarization dependent gain(PDG) and mode coupling are three factors that may synchronously influence the transmission of single-wavelength polarized light in optical fibers.This paper obtains a new Mueller matrix analysis,which can be used under conditions that all these three factors are existing and changing.According to our transmission model,the state of polarization(SOP) changes along an optical microstructure fiber with co-existence of birefringence-PDG-mode coupling were simulated.The simulated results, which show the phenomena of SOP constringency,are in good agreement with previous theoretical analyses.展开更多
Optical buffers are critical for optical signal processing in future optical packet-switched networks. In this paper, a theoretical study as well as an experimental demonstration on a new optical buffer with large dyn...Optical buffers are critical for optical signal processing in future optical packet-switched networks. In this paper, a theoretical study as well as an experimental demonstration on a new optical buffer with large dynamical delay time is carried out based on cascaded double loop optical buffers (DLOBs). It is found that pulse distortion can be restrained by a negative optical control mode when the optical packet is in the loop. Noise analysis indicates that it is feasible to realise a large variable delay range by cascaded DLOBs. These conclusions are validated by the experiment system with 4-stage cascaded DLOBs. Both the theoretical simulations and the experimental results indicate that a large delay range of 1-9999 times the basic delay unit and a fine granularity of 25 ns can be achieved by the cascaded DLOBs. The performance of the cascaded DLOBs is suitable for the all optical networks.展开更多
To combine the technical functions and advantages of solid-core fiber Bragg gratings(FBGs) and hollow-core optical fibers(HCFs), the hollow and filled FBGs in nano-bore optical fibers(NBFs) with nano-bore in the GeO2-...To combine the technical functions and advantages of solid-core fiber Bragg gratings(FBGs) and hollow-core optical fibers(HCFs), the hollow and filled FBGs in nano-bore optical fibers(NBFs) with nano-bore in the GeO2-doped core are proposed.The fundamental mode field, effective mode index, and confinement loss of NBF with 50 nm–7 μm-diameter hollow and filled nano-bore are numerically investigated by the finite element method.The reflected spectra of FBGs in NBFs are obtained by the transmission matrix method.The hollow FBGs in NBFs can be acheived with ~5% power fraction in the bore and the ~0.9 reflectivity when bore diameter is less than 3 μm.The filled FBGs can be realized with^1% power fraction and 0.98 reflectivity with different fillings including o-xylene, trichloroethylene, and chloroform for 800-nm bore diameter.The feasibility of the index sensing by our proposed NBF FBG is also analyzed and discussed.The experimental fabrication of hollow and filled FBGs are discussed and can be achieved by current techniques.The aim of this work is to establish a principle prototype for investigating the HCFs and solid-core FBGs-based fiber-optic platforms,which are useful for applications such as the simultaneous chemical and physical sensing at the same position.展开更多
An interferometer with double loops based on a planar 3 × 3 coupler is proposed.The main factors that cause the instability of the polarization state are obtained by theoretical analysis and experiment.Furthermor...An interferometer with double loops based on a planar 3 × 3 coupler is proposed.The main factors that cause the instability of the polarization state are obtained by theoretical analysis and experiment.Furthermore,the stability of the polarization state is described quantitatively by the time-varying vector of polarization.Using these effective measures,interference with a stable polarization state at all times is achieved.展开更多
Polarization-based optical communications are attracting more attention recently, where the crucial points are polarization features and their measurements. Based on the Müller matrix method, we obtain measurable...Polarization-based optical communications are attracting more attention recently, where the crucial points are polarization features and their measurements. Based on the Müller matrix method, we obtain measurable expressions for the polarization-dependent gain(PDG) and the loss of polarization orthogonality(LPO), while give the boundary of the LPO for any PDG devices. We experimentally demonstrate that non-linear LPO can be created in a semiconductor optical amplifier and find that the LPO will slightly skim over the boundary near the threshold of the injected current. Furthermore, an empirical formula is achieved to gauge the LPO-induced power penalty, which is proven to be valid in differential polarization shift-keying transmission by executing a bit error rate measurement. Our conclusions are applicable to non-orthogonal polarization cases and valuable to polarization-related communications, even orbital angular momentum multiplexing.展开更多
In this paper,a novel all-solid anti-resonant single crystal fiber(AR-SCF)with high refractive index tubes cladding is proposed.By producing the cladding tubes with high refractive index material,the AR guiding mechan...In this paper,a novel all-solid anti-resonant single crystal fiber(AR-SCF)with high refractive index tubes cladding is proposed.By producing the cladding tubes with high refractive index material,the AR guiding mechanism can be realized for the SCF,which can reduce the mode number to achieve single-mode or few-mode transmission.The influences of dif-ferent materials and structures on the confinement loss and effective guided mode number for wavelengths of 2-3μm are investigated.Then,the optimal AR-SCF structures for different wavelengths are determined.Furthermore,the influences of different fabrication errors are analyzed.This work would provide insight to new opportunities in the novel design of SCFs by AR,which would greatly impact the fields of laser application,supercontinum generation,and SCF sensors.展开更多
基金supported by the National Natural Science Foundation of China(Grants Nos.60877057 and 60907027)
文摘Birefringence(polarization-related phase-shift),polarization dependent gain(PDG) and mode coupling are three factors that may synchronously influence the transmission of single-wavelength polarized light in optical fibers.This paper obtains a new Mueller matrix analysis,which can be used under conditions that all these three factors are existing and changing.According to our transmission model,the state of polarization(SOP) changes along an optical microstructure fiber with co-existence of birefringence-PDG-mode coupling were simulated.The simulated results, which show the phenomena of SOP constringency,are in good agreement with previous theoretical analyses.
基金supported by the State Key Development Program for Basic Research of China (Grant No.2010CB328300)the National Natural Science Foundation of China (Grant Nos.60677004 and 60702049)+1 种基金the Program for the New Century Excellent Talents in University of China (Grant No.NECT-07-0111)the Innovation Plan for Youth of Beijing University of Posts and Telecommunications
文摘Optical buffers are critical for optical signal processing in future optical packet-switched networks. In this paper, a theoretical study as well as an experimental demonstration on a new optical buffer with large dynamical delay time is carried out based on cascaded double loop optical buffers (DLOBs). It is found that pulse distortion can be restrained by a negative optical control mode when the optical packet is in the loop. Noise analysis indicates that it is feasible to realise a large variable delay range by cascaded DLOBs. These conclusions are validated by the experiment system with 4-stage cascaded DLOBs. Both the theoretical simulations and the experimental results indicate that a large delay range of 1-9999 times the basic delay unit and a fine granularity of 25 ns can be achieved by the cascaded DLOBs. The performance of the cascaded DLOBs is suitable for the all optical networks.
基金Project supported by the Beijing Natural Science Foundation,China(Grant No.4192047)the Fundamental Research Funds for the Central Universities,China(Grant Nos.2018JBM070 and 2018JBM065)the National Natural Science Foundation of China(Grant No.61675019)
文摘To combine the technical functions and advantages of solid-core fiber Bragg gratings(FBGs) and hollow-core optical fibers(HCFs), the hollow and filled FBGs in nano-bore optical fibers(NBFs) with nano-bore in the GeO2-doped core are proposed.The fundamental mode field, effective mode index, and confinement loss of NBF with 50 nm–7 μm-diameter hollow and filled nano-bore are numerically investigated by the finite element method.The reflected spectra of FBGs in NBFs are obtained by the transmission matrix method.The hollow FBGs in NBFs can be acheived with ~5% power fraction in the bore and the ~0.9 reflectivity when bore diameter is less than 3 μm.The filled FBGs can be realized with^1% power fraction and 0.98 reflectivity with different fillings including o-xylene, trichloroethylene, and chloroform for 800-nm bore diameter.The feasibility of the index sensing by our proposed NBF FBG is also analyzed and discussed.The experimental fabrication of hollow and filled FBGs are discussed and can be achieved by current techniques.The aim of this work is to establish a principle prototype for investigating the HCFs and solid-core FBGs-based fiber-optic platforms,which are useful for applications such as the simultaneous chemical and physical sensing at the same position.
文摘An interferometer with double loops based on a planar 3 × 3 coupler is proposed.The main factors that cause the instability of the polarization state are obtained by theoretical analysis and experiment.Furthermore,the stability of the polarization state is described quantitatively by the time-varying vector of polarization.Using these effective measures,interference with a stable polarization state at all times is achieved.
基金supported by the National Natural Science Foundation of China (Nos.11274037 and 11574026)the Program for New Century Excellent Talents in University, MOE of China (No.NCET-120765)the Foundation for the Author of National Excellent Doctoral Dissertation, China (No.201236)
文摘Polarization-based optical communications are attracting more attention recently, where the crucial points are polarization features and their measurements. Based on the Müller matrix method, we obtain measurable expressions for the polarization-dependent gain(PDG) and the loss of polarization orthogonality(LPO), while give the boundary of the LPO for any PDG devices. We experimentally demonstrate that non-linear LPO can be created in a semiconductor optical amplifier and find that the LPO will slightly skim over the boundary near the threshold of the injected current. Furthermore, an empirical formula is achieved to gauge the LPO-induced power penalty, which is proven to be valid in differential polarization shift-keying transmission by executing a bit error rate measurement. Our conclusions are applicable to non-orthogonal polarization cases and valuable to polarization-related communications, even orbital angular momentum multiplexing.
基金This work was supported in part by the Fundamental Research Funds for the Central Universities(No.2019JBM345)in part by the Beijing Natural Science Foundation(No.4192047)in part by the National Natural Science Foundation of China(Grant No.61875064).
文摘In this paper,a novel all-solid anti-resonant single crystal fiber(AR-SCF)with high refractive index tubes cladding is proposed.By producing the cladding tubes with high refractive index material,the AR guiding mechanism can be realized for the SCF,which can reduce the mode number to achieve single-mode or few-mode transmission.The influences of dif-ferent materials and structures on the confinement loss and effective guided mode number for wavelengths of 2-3μm are investigated.Then,the optimal AR-SCF structures for different wavelengths are determined.Furthermore,the influences of different fabrication errors are analyzed.This work would provide insight to new opportunities in the novel design of SCFs by AR,which would greatly impact the fields of laser application,supercontinum generation,and SCF sensors.