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- 实验方案
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An optical angle sensor based on chromatic dispersion with a mode-locked laser source
摘要： This paper proposes a new optical angle sensor, in which a mode-locked laser is employed as the light source, and chromatic dispersion of a collimator objective is utilized to detect the angular displacement of a target of interest. In the proposed method, each of the optical modes in the femtosecond laser beam reflected from the reflector mounted on a target of interest is separated from the others by chromatic dispersion of a collimator objective to generate a group of focused laser beams that can be utilized as the scale for measurement of an angular displacement of the target. By detecting the change in peak frequency in optical spectra obtained by the photodetector, a small angular displacement can be measured. In this paper, as the first step of research, a prototype optical setup is developed, and some basic experiments are carried out to demonstrate the feasibility of the proposed method for measurement of angular displacement.
关键词： Chromatic dispersion,Angular displacement,Angle measurement,Optical frequency comb,Laser autocollimation
更新于2025-11-28 14:24:03
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Study of Chromatic Dispersion Impacts on Kramers-Kronig and SSBI Iterative Cancellation Receiver
摘要： Field recovery of single sideband (SSB) signals with direct detection has recently been investigated for short-reach communications. One of the cruxes of such direct-detected transmission system is signal-signal beat interference (SSBI) mitigation without sacrificing spectral efficiency. Among various digital signal processing schemes, Kramers-Kronig (KK) algorithm has attracted considerable interest recently due to its effective mitigation of SSBI, and the phase of signals can be recovered using intensity information. As such, chromatic dispersion (CD) can be digitally compensated. Beside KK algorithm, SSBI can also be sufficiently mitigated iteratively. In this paper, we carry out an 80-Gb/s 160-km transmission experiment to investigate chromatic dispersion impacts on both KK and SSBI iterative cancellation (IC) receiver. It is shown that for KK receiver, optimal carrier-to-signal power ratio (CSPR) values increase with transmission distance. This is because that CD induced peak-to-average power ratio (PAPR) increase violates minimum phase condition, and thus the field cannot be reconstructed accurately, leading to degradation of transmission performance. Consequently, OSNR sensitivity for KK receiver is dependent on CD. In contrast, IC receiver has no limitation of minimum phase condition, and thus exhibits high robustness against CD regardless of CSPRs. Besides, experimental results show that after 160-km transmission at the BER threshold of 10-3, the required OSNR for IC receiver is 1.9 dB lower than that of KK receiver.
关键词： direct detection,Kramers-Kronig receiver,virtual single sideband signal,signal-signal beat interference,Chromatic dispersion
更新于2025-09-23 15:22:29
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Interplay of Bit Rate, Linewidth, Bandwidth, and Reach on Optical DMT and PAM with IMDD
摘要： We theoretically compare the performance of optical discrete multi-tone (DMT) and pulse amplitude modulation (PAM) using intensity modulated, direct detection (IMDD). PAM is a lower cost, lower complexity solution than DMT, however it is more vulnerable to chromatic dispersion on the C band. We compare DMT and PAM taking into consideration the interplay of laser linewidth, fiber length, transmission rate, and channel bandwidth. We use a semi-analytical model to examine bit error rates. We study how system parameters shift the performance advantages between DMT and PAM. Our model can also be used to find the best hardware solution and frequency band for a target modulation format and bit error rate.
关键词： PAM,O-band,C-band,chromatic dispersion,DMT,bandwidth,laser linewidth
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET) - Chennai (2018.3.22-2018.3.24)] 2018 International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET) - Performance Analysis for Mixed Line Rates (MLR) WDM/DWDM Networks Under Various Modulation Techniques
摘要： In recent years, a rapid growth of new technologies requires communication systems to support higher bit rate and longer distance. The Optical network is one of the best optimal solutions which can satisfy the demand for high data rate. The performance of current optical networks depends on the traffic demands. To minimize the traffic mixed line rate (MLR) optical network is implemented. In a transparent MLR optical network, data transmission is done over different wavelength at different line rates within the same fiber. MLR optical networks with data rate 10/40/100 Gb/s over different wavelength channels is a new networking paradigm. This paper considers various modulation techniques in order to achieve better bit error rates (BER). It also shows that modulation technique has a great role in improving the data rates and quality of transmission.
关键词： Wavelength division multiplexing/Dense wavelength division Multiplexing (WDM/DWDM),Bit error rate,Chromatic dispersion,Mixed line rates,Physical layer impairments,Amplifier spontaneous emission
更新于2025-09-23 15:22:29
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As2Se3-Ge11.5As24Se64.5 based mid-infrared dual nano-slot optical waveguide with huge and wavelength tunable dispersion
摘要： An As2Se3-Ge11.5As24Se64.5 based dual nano-slot waveguide with huge chromatic dispersion at mid-infrared is proposed. The large chromatic dispersion at the target wavelength is achieved induced by resonance interaction. The characteristics of dispersion are investigated by employing the FDTD method. The simulation results indicate that by optimizing the geometrical parameters, the maximum dispersion of -3.48×105 ps·nm-1·km-1 over a full width at FWHM of 2 nm at 3000 nm has been attained. A flat and ultra-large dispersion of -3.48×105 ps·nm-1·km-1 from 2980 to 3010 nm is achieved by cascading the dual-slot waveguides. The relative dispersion magnitude fluctuation is less than 1.85%.
关键词： chalcogenide waveguide,chromatic dispersion,dual-slot waveguide,mid-infrared
更新于2025-09-23 15:21:01
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Mid-infrared supercontinuum generation with high spectral flatness in dispersion flattened tellurite all-solid hybrid microstructured optical fibers
摘要： Tellurite all-solid hybrid microstructured optical fibers are proposed for chromatic dispersion control. An ultra-flattened chromatic dispersion profile with variation as small as ± 0.2 ps/km/nm over the wavelength range from 2.5 to 3.7 μm can be obtained. The fibers with flattened chromatic dispersion profiles have high potential for broadband mid-infrared supercontinuum generation. Fabrication of the fiber is successfully performed and by pumping the fabricated fiber at 2 μm, a broad and highly coherent supercontinuum with high spectral flatness is generated.
关键词： mid-infrared,supercontinuum generation,microstructured optical fibers,tellurite fibers,chromatic dispersion
更新于2025-09-23 15:19:57
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[IEEE 2018 11th International Symposium on Communication Systems, Networks and Digital Signal Processing (CSNDSP) - Budapest (2018.7.18-2018.7.20)] 2018 11th International Symposium on Communication Systems, Networks & Digital Signal Processing (CSNDSP) - Using Tunable Dispersion-Compensated Modules to Overcome the Power Penalty of a Millimeter-Wave Opto-Electronic Oscillator Signal that is Distributed via a Passive Optical Network for 5G Networks
摘要： The opto-electronic oscillator (OEO), used as a high-frequency oscillator to produce millimeter-wave (mm-W) signals with a low phase noise, is a suitable candidate for fifth-generation (5G) networks in the mm-W range. Since a mm-W OEO is too expensive for every 5G base-station, another option is to employ the OEO at the central-office to feed the base-stations via a passive optical network (PON) infrastructure. The lengths of the PON branches introduce a large power penalty to the transmitted mm-W OEO signal due to the chromatic dispersion of the optical fiber. In this paper the idea of upgrading the PON branches with tunable dispersion-compensated modules to have power-penalty-free transmission is proposed. By overcoming the power-penalty problem in the mm-W range, the integrated optical dispersion-compensated modules are used to minimize the influence of the dispersion in the standard single-mode optical fiber used in the PON.
关键词： power penalty,5G mobile networks,chromatic dispersion,tunable dispersion-compensated module
更新于2025-09-19 17:15:36
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Optimisation of Dispersion Flatness in Nanostructured Core Fibres
摘要： Nanostructured optical fibres allow to obtain an arbitrary profile of refraction index in the core. These fibres are composed of several thousands of rods with diameter smaller than incident wavelength. Their optical performance is described with the Maxwell-Garnett effective medium theory. A modification of nanorods distribution or doping level in nanorods allow controlling of chromatic dispersion, polarization and modal properties of the nanostructured fibres. We study an influence of additional microrings in the core on fibre dispersion characteristics. We consider a fibre composed of pure silica nanorods and silica nanorods highly doped with Ge (concentration of GeO2 equals 20% mol). Modification of core internal structure affects electric field distribution in the fundamental mode, and consequently results in changes of its dispersion characteristics. We show that flat, all-normal dispersion characteristics (≈ 2.5 ps/nm/km) in wavelength range from 1.3 up to 2.15 μm can be achieved in the optimized structure. Moreover, within these limits, 1.5 μm to 1.9 μm range was revealed to be ultra-flat (≈ 0.2 ps/nm/km). In contrast to already reported in the literature similar fibres, proposed design is based on fused silica glasses, exhibits spectrally broader and more flat dispersion profile, it is an all-solid construction and it has the effective mode area equal 13μm2 for λ=1.55μm wavelength. Thanks to such characteristics, the fiber allows free from higher order distortions light propagation of highly confined broadband optical pulses, what might find applications in ultrafast optics, or dispersion management systems.
关键词： ultrafast optics,Maxwell-Garnett effective medium theory,chromatic dispersion,nanostructured optical fibres,all-normal dispersion
更新于2025-09-16 10:30:52
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Numerical study on a proposed photonic crystal fiber with large modal separation
摘要： We investigate the characteristics of optical modes in a new designed hollow-core photonic crystal fiber (PCF), including the large effective refractive index difference between four vector beams and chromatic dispersion.
关键词： chromatic dispersion,Modal separation,effective refractive index,photonic crystal fiber
更新于2025-09-16 10:30:52
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Lengthwise Measurement of Chromatic Dispersion along an Optical Fiber Transmission Link with Enhanced Correction Factor
摘要： In recent years optical time domain reflectometer (OTDR)-based techniques have become a known practice for measuring chromatic dispersion (CD) distribution along an optical fiber transmission link. In this paper, a measurement technique which uses a four-wavelength bidirectional OTDR to evaluate the CD distribution along the length of an optical fiber transmission system has been presented. A novel formulation has been developed for this nondestructive technique to improve the correction factor, which leads to an improvement in the CD and mode field diameter (MFD) measurement. The obtained experimental outcomes are in good agreement with those obtained by the interferometric technique.
关键词： backscattering,MFD,OTDR,chromatic dispersion
更新于2025-09-16 10:30:52