- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Ultrafast Pulse Manipulation in Dispersion-Flattened Waveguides With Four Zero-Dispersion Wavelengths
摘要： On-chip formation and manipulation of ultrashort pulses would be of great interest to ultrafast optics and integrated photonics communities. One of key issues is dispersion-assisted nonlinear interactions of broadband frequency components. In this paper, we show for the first time that a bilayer waveguide for quasi-TE mode without using a slot produces a quite flat and saddle-shaped dispersion profile. Different from previously reported TE-mode waveguides with flattened dispersion, the proposed waveguide exhibits a greatly simplified structure with no need for a high-aspect-ratio slot and has quite small group delay difference in a wide spectral range with four zero-dispersion wavelengths (ZDWs). We study supercontinuum generation in hybrid dispersion regime for the first time, in which the broadened spectrum covers a bandwidth with all ZDWs. It is found that one can obtain greatly improved spectral flatness in supercontinuum generation, with a power variation as small as 3 dB over a bandwidth of >500 nm. Moreover, the proposed waveguides are particularly suitable for low-distortion pulse propagation over a long distance, which is important for on-chip ultrashort pulse delivery.
关键词： Dispersion engineering,pulse compression,waveguide,supercontinuum generation
更新于2025-09-12 10:27:22
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Supercontinuum Generation from a Thulium Ultrafast Fiber Laser in a High NA Silica Fiber
摘要： A broadband supercontinuum is generated from a thulium ultrafast soliton fiber laser in a high numerical aperture silica fiber with low nJ seed pulse energies. Amplification of a thulium based ultrafast soliton ring fiber laser in two customized thulium doped fiber amplifiers provides pulses varying in energy between 1.8 nJ and 13.5 nJ. Coupling these seed pulses into a high numerical aperture silica fiber UHNA 7 of varying length, a systematic study of the impact of pulse energy, pulse duration and nonlinear fiber length is conducted. Based on the normal dispersion, self-phase modulation dominates for lower pump power values and results in a symmetric spectral broadening process. For higher pulse energies, four-wave mixing and Raman scattering contribute to a strong red-shift of the spectrum beyond 2.3 μm. For a fiber length of 20 m of UNHA 7, a broadband supercontinuum spanning from 1.7 μm to 2.33 μm is generated with a 20 dB spectral bandwidth of 502 nm with an output pulse energy of 4.4 nJ, corresponding to an output power of 92 mW. This represents a low seed energy threshold for efficient flat supercontinuum generation at infrared wavelengths.
关键词： Supercontinuum generation,Ultrafast optics,Fiber lasers,Thulium
更新于2025-09-12 10:27:22
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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) - Compact One-Octave Spanning Supercontinuum Generation by Amplification of Noise like Pulses in Yb-Doped Fiber Amplifier
摘要： Currently, supercontinuum source has found wide applications in different area of science and technology. Optical frequency meteorology [1], spectroscopy [2], optical coherence tomography [3] and high-speed optical communication [4] are among the most prominent application of supercontinuum light sources. Recently, using noise like pulses(NLPs) for generating supercontinuum sources have attracted attention [5,6]. In this work, we demonstrate a high power broad supercontinuum source by amplifying NLPs in fiber amplifier in the nonlinear regime.
关键词： nonlinear regime,Yb-doped fiber amplifier,noise like pulses,supercontinuum generation
更新于2025-09-12 10:27:22
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Design and Analysis of a Dispersion-engineered and Highly Nonlinear Rib Waveguide for Generation of Broadband Supercontinuum Spectra
摘要： In this paper, a waveguide consisting of a core of As2Se3 chalcogenide glass and the upper and lower claddings of MgF2 with two zero-dispersion wavelengths (ZDW) has been proposed. By optimization of the dimensions of the core and the claddings, their effects on the dispersion curve have been investigated and a suitable structure with a flat dispersion curve, an effective mode area of 1.6 μm2 in a pump wavelength of 2.8 μm, and hence, a nonlinear coefficient greater than 34 w?1 m?1 has been obtained. A broadband supercontinuum in a wavelength range of 1.5 μm to 15 μm has been generated by applying an input pulse with duration of 100 fs and a maximum power of 2 kw to this waveguide. Due to the large width of the supercontinuum generated (SCG), the short length of the waveguide (maximum 5 mm), and a low input power, this structure is suitable for use in optical integrated circuits and its various applications.
关键词： zero dispersion wavelength,supercontinuum generation,high nonlinearity,chalcogenide glass,low loss,rib waveguide
更新于2025-09-12 10:27:22
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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) - Spatial Kerr Beam Self-Cleaning in Yb-Doped Multimode Fiber Taper
摘要： Spatial Kerr beam self-cleaning (KBSC), which transforms an output speckled beam in a quasi-single mode beam in graded index (GRIN) multimode optical fibers (MMFs), has been reported recently [1,2]. GRIN MMFs are also interesting waveguides for supercontinuum (SC) generation in the visible and near infrared regions, as successfully demonstrated by launching femtosecond or subnanosecond pulses in the anomalous (1550 nm) or normal (1064 nm) dispersion regime, respectively [1,3]. The spectral broadening features were explained through the interplay between spatiotemporal multimode soliton oscillations and dispersive wave generation in fibers with parabolic index profile. On the other hand, tapered optical fibers are well known to provide a number of useful features, including strong mode confinement capability, small scale diameter and broad SC generation [4,5]. Herein, we report visible-short infrared SC generation in combination with KBSC in long (~10 m) tapered Yb-doped MMFs, with parabolic index profile and parabolic doping concentration.
关键词： supercontinuum generation,Spatial Kerr beam self-cleaning,graded index multimode optical fibers,Yb-doped multimode fiber taper
更新于2025-09-12 10:27:22
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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) - Generation of Broad-Band Circularly Polarised Supercontinuum in Chiral Photonic Crystal Fibre
摘要： Supercontinuum (SC) generation in solid-core photonic crystal fibres (PCFs) is well established and has diverse applications in science and technology [1,2]. In a conventional SC, the polarization state is not maintained over the whole spectrum due to cross-phase modulation and may in addition vary with power. Recently, it has been reported that continuously twisted PCFs exhibit circular birefringence [3,4]. Here we report the first experimental demonstration of a twisted PCF that robustly maintains circular polarization state across the whole spectrum, independent of power.
关键词： Supercontinuum generation,chiral light-matter interactions,photonic crystal fibres,circular polarization
更新于2025-09-12 10:27:22
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Nonlinear Fiber Optics || Multimode fibers
摘要： Multimode fibers were first used for nonlinear optics during the 1970s because most optical fibers available at that time supported multiple modes. The situation changed in the 1980s when single-mode fibers were commercialized in view of their telecommunication applications. The interest in multimode fibers re-surfaced after 2005, partly motivated by their use for space-division multiplexing in optical communication systems. As a byproduct of this interest, the nonlinear effects in multimode fibers have been studied extensively since 2010. This chapter covers recent advances in a systematic fashion. Three types of multimode fibers are introduced in Section 14.1, where we also discuss modes supported by them. Section 14.2 extends theory of Section 2.3 to obtain a set of coupled nonlinear equations for various fiber modes. These equations are used in Sections 14.3 to discuss modulation instability and soliton formation in multimode fibers. The focus of Section 14.4 is on the intermodal nonlinear effects that transfer energy among the modes. The spatio-temporal effects are discussed in Section 14.5 with emphasis on spatial beam cleanup and supercontinuum generation through multimode fibers. Section 14.6 is devoted to the nonlinear phenomena in multicore fibers.
关键词： modulation instability,spatio-temporal effects,spatial beam cleanup,soliton formation,multimode fibers,multicore fibers,supercontinuum generation,nonlinear optics,space-division multiplexing,intermodal nonlinear effects
更新于2025-09-12 10:27:22
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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) - Supercontinuum Generation in a As <sub/>2</sub> S <sub/>3</sub> -Silica Nanospike Waveguide Pumped by Tm-Doped Fiber Laser
摘要： The development of compact bright supercontinuum (SC) sources is of particular interest, especially in the mid-IR where is a lack of suitable sources [1,2]. Here we report first results on SC generation in a As2S3-silica dual nanospike waveguide [3, 4] pumped in different multi-pulse regimes by a high-power femtosecond Tm-doped fiber laser mode-locked by nonlinear polarization evolution [5-7]. The experimental set-up is sketched in Fig. 1a. The central wavelength of the laser is 1890 nm and its repetition rate is 13 MHz. By tuning the polarization controllers (PC1 and PC2) in the ring cavity [8], the laser could be configured to operate in different multi-pulse regimes, namely noise-like pulses, soliton bunches and soliton “rain”. The pulse duration is 931 fs in both soliton regimes. The coherence time of the noise-like pulses is 228 fs. The pulses were free-space launched into the As2S3-silica dual nanospike waveguide designed to improve the launch efficiency in and out of the waveguide (~20%). The central uniform portion of the hybrid nanospike has a core diameter of 1.1 μm, the group velocity dispersion (GVD) curve of which is plotted in the inset of Fig. 1a. The pump wavelength is in the anomalous dispersion region between two zero dispersion wavelengths. The measured SC spectra are shown in Fig. 1b for the regimes of soliton bunches (top) and noise-like pulses (bottom). The results from the soliton “rain” regime (not shown here) and the soliton bunches regime are similar. In the soliton regime, sidebands originating from self-phase modulation are observed for a launched peak power of ~90 W, with the spectrum spanning from 1650 nm to 2200 nm. The launched peak power of the solitons was estimated by the pulse duration and the laser characteristics after taking into account the coupling efficiency. The black-dashed line in Fig. 1b plots the simulated spectrum at the output end of the dual nanospike, agreeing reasonably well with experiment. In the preliminary simulation, a single pulse with the same peak power (90 W) was launched into the model. When pumping the waveguide by noise-like pulses the spectrum barely broadens, probably due to the smaller peak power of a single pulse in the packet. In summary, we have achieved spectral broadening in a As2S3-silica hybrid waveguide pumped in different multi-pulse regimes at 1890 nm. It appears that soliton-like regimes are preferable for SC generation. The system is promising for realizing all-fiber broadband SC sources using well-defined femtosecond pulses, as well as investigating different mechanisms of SC generation in multi-pulse regimes.
关键词： mid-IR,Tm-doped fiber laser,supercontinuum generation,As2S3-silica nanospike waveguide,multi-pulse regimes
更新于2025-09-12 10:27:22
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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) - Chalcogenide Glass Polarization-Maintaining Photonic Crystal Fiber for Mid-Infrared Supercontinuum Generation
摘要： Chalcogenide-glass-based optical fibers are excellent photonic platforms for nonlinear applications in the mid-IR region due to their wide transmission window, tunable dispersion and high optical nonlinearity. There is particular interest in combining the chalcogenide fiber platform with polarization-preserving properties as this will allow polarization-dependent measurements while minimizing detrimental effects and thus enable new applications in interferometric techniques, gas sensing, integrated-optic devices and optical coherence tomography. In this work, for the first time to our knowledge, we demonstrate mid-IR supercontinuum (SC) generation in a highly birefringent polarization maintaining photonic crystal fiber (PM-PCF). The PM-PCF was drawn using the casting method from As38Se62 glass which features a transmission window from 2-10 μm and a high nonlinear refractive index up to 1.13×10-17 m2/W [1,2]. To introduce strong birefringence, an asymmetric arrangement of air holes was used as shown in Fig. 1(a). The PCF cross section consists of 36 circular air holes in 3 rings with 2 larger air holes adjacent to the core. The (approximate) core diameter (i.e. distance between two large air holes) is ~8.1 μm and the outer diameter of the PCF is 125 μm. The group velocity dispersion and group birefringence for the fundamental mode (computed from the SEM image) are shown in Fig. 1(b). The fiber has a zero-dispersion wavelength around 4.5 μm and, at this wavelength, a large birefringence of 6×10-4 such that strong polarization maintaining properties are expected. In our experiments, a 25cm long PM-PCF was pumped with 250 fs pulses at 4 μm (i.e. the normal dispersion regime) using the same experimental setup for MIR SC generation as previously described in Ref. [3]. Figure 1(c) shows the generated SC spectra with different output power. For a pump power of 135 mW, we obtained a SC spectrum from 3.1-6.02 μm with an average output power of 11 mW. Pumping close to the zero dispersion wavelength with the pump at 4.53 μm yielded comparable spectral broadening but at much lower input pump power of 62 mW as shown in Fig. 1(d). In this case, we were able to measure the polarization dependence of the SC spectra by changing the coupling angle through rotation of the fiber. These results demonstrate the potential of chalcogenide PM-PCF for polarized SC generation, and work is underway to optimize the spectral generation and polarization dependency using detailed numerical modelling.
关键词： Polarization-maintaining,Photonic crystal fiber,Chalcogenide glass,Mid-infrared,Supercontinuum generation
更新于2025-09-12 10:27:22
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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) - Customizing Supercontinuum Generation Via Adaptive On-Chip Pulse Splitting
摘要： Modern optical systems increasingly rely on complex physical processes. Advanced light sources, such as supercontinuum (SC) [1], are highly sought for imaging and metrology, and are based on nonlinear dynamics where the output properties must often finely match target performance characteristics. However, in these systems, the availability of control parameters and the means to adjust them in a versatile manner are usually limited. Moreover, finding the ideal parameters for a specific application can become inherently complex. Here, we use an actively-controlled photonic chip to prepare and manipulate patterns of femtosecond optical pulses seeding supercontinuum generation [1]. Taking advantage of machine learning concepts [2], we exploit this access to an enhanced and tunable parameter space and experimentally demonstrate the customization of nonlinear interactions responsible for tailoring supercontinuum properties [3].
关键词： femtosecond optical pulses,supercontinuum generation,photonic chip,machine learning,nonlinear dynamics
更新于2025-09-12 10:27:22