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Single- and dual-wavelength switchable mode-locked dissipative soliton Yb-doped fiber laser based on graphene/WS <sub/>2</sub> nanocomposites modelocker and polarization controller
摘要： We report a single- and dual-wavelength switchable mode-locked dissipative soliton in an ytterbium-doped fiber laser based on graphene/WS2 nanocomposites saturable absorber. The graphene/WS2 nanocomposites film possesses efficient saturable absorption characteristics with large modulation depth (45.1%), which results in the stable single-wavelength mode-locking operation with pulse duration of 450 ps. By carefully rotating the polarization controller, the mode-locking operation can be switched to a dual-wavelength at both 1066.4 nm and 1069.2 nm due to the modulation of the intracavity birefringence. Our work extends the studies for 2D nanomaterials and supplies potential applications in the multi-wavelength fiber laser.
关键词： mode-locked fiber laser,saturable absorber,dual-wavelength,graphene/WS2 nanocomposites,dissipative soliton
更新于2025-09-11 14:15:04
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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) - Dual-Wavelength Dual-Comb Mode Locked Er-Doped Fiber Laser Based on Saganc Fiber Loop Mirror
摘要： We report an all-fiber dual-wavelength dual-comb mode locked fiber laser based on a Sagnac fiber loop mirror. Two asynchronous mode locked pulse trains with repetition rate difference of 218 Hz was realized.
关键词： fiber laser,Sagnac fiber loop mirror,mode locked,dual-wavelength,dual-comb
更新于2025-09-11 14:15:04
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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) - Hyperspectral Imaging of Bio-Inspired Tilted Cholesteric Liquid Crystal Structures
摘要： The cholesteric liquid crystal (CLC) phase exhibits a helical structure with a twist axis perpendicular to the local molecular director. When light propagates in the Bragg regime through a CLC slab with a planar texture, the medium gives rise to Bragg reflection, selective in wavelength and in polarization. The characteristics of the Bragg band are tunable by acting on the following structural parameters: the pitch, the helicity sense and the helix orientation. Tuning the latter parameter produces polygonal textures (Fig. 1, center). Such a texture is made of an array of micrometer-scale polygonal cells, acting a network of microlenses with wavelength-tunable focusing properties [1]. Polygonal textures can be found in biological CLCs (for instance, multiwavelength micromirrors the cuticle of scarab beetle Chrysina gloriosa [2]). Here, we perform jointly spectral and spatial characterization of CLCs with oblique helicity through a liquid-crystal-based hyperspectral imaging (HSI), which is a compact and non-destructive technique ideally adapted to characterize mesoscopic samples, both in transmission and reflection [3]. Although liquid crystal have already been used to perform multispectral and hyperspectral imaging, they have not been, to date, the subject of an HSI study. The instrument output is an image with 512*128 pixels, each of them being spectrally resolved. Spectro-spatial properties of the polygonal texture are then measured with unprecedented spectral resolution for tilted CLCs, that is 6 nm over 400-1000nm, while conventional multispectral imaging is limited to a spectral resolution of a few tens of nanometers. Our experimental results are summarized in Fig. 1. In transmission, the mesoscopic chromatic pattern of the studied sample is recovered, and its wavelength-tunable light shaping properties are emphasized with the reconstruction of the hyperspectral datacube of a quarter of polygon. Furthermore, the reflected light analysis of a single polygon (lateral dimension below 15μm) reveals the local tilting of the CLC helical axis, that is the bulk distortion constituting the texture. The signature resides in the fine tuning of the spectral characteristics of the bandgap into the part of a polygon in which the orientation of the helix axis is spatially changing. A correlation between spatial changes and spectral changes on a mesoscopic scale is therefore made possible [4]. These results demonstrate the interest of hyperspectral imaging for the precise study of complex cholesteric components, also existing in biological samples. It thus opens many perspectives to enrich and deepen our knowledge on the fine structure of these materials. Additionally, it is found that polygonal textures may offer practical solutions in numerous applications, from secure authentication to information-enriched imaging, and, particularly, in the field of cryptography.
关键词： wavelength-tunable,Bragg reflection,polygonal textures,cholesteric liquid crystal,hyperspectral imaging
更新于2025-09-11 14:15:04
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Design of high-performance and tunable magneto-optical isolators for He–Ne laser
摘要： Herein, we report on high-performance magnetophotonic crystal (MPC) structures, which can be adjusted to create perfect magneto-optical isolators (MOIs) for helium–neon lasers operating at a wavelength of 632.8 nm. The adjustment is carried out by tuning the applied magnetic field to use the high potential of the CeF3 as a new and transparent visible Faraday rotator. For practical purposes, to avoid instabilities due to wavelength fluctuations, we show that achieving a suitable tunable MOI with a flat-top response is possible when the appropriate MPC design is approached.
关键词： wavelength 632.8 nm,magneto-optical isolator,He–Ne laser,magnetic field tunability
更新于2025-09-11 14:15:04
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[IEEE 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC) - Fukuoka, Japan (2019.7.7-2019.7.11)] 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC) - SDN enabled dynamically re-configurable low-cost ROADM nodes for metro networks
摘要： We demonstrate dynamically re-configurable and contention-free metro-access ring based on low-cost SOA 2-degree mini-ROADMs providing both switching and amplification. Results show successful SDN-assisted multiple add/drop 10Gbps WDM traffic in metro-access ring with <1dB power penalty.
关键词： Switching Systems,Wavelength switching,Reconfigurable optical add-drop mux/demux
更新于2025-09-11 14:15:04
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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) - All-Fiber System at 1750 nm Delivering 35 fs 230 kW Peak Power Pulses
摘要： Ultra-short (<70 fs) pulses in the short-wavelength infrared (>1.55 μm) are very attractive for many applications such as three-photon microscopy1, frequency metrology2, or high harmonic generation3. Solitonic self-compression is an attractive effect for this purpose as compression to sub-50 fs pulses can be achieved without the need for external compressing optics, directly out of an optical fiber. Self-compression at high energy was demonstrated around 2 μm in all-solid4 or gas-filled5 hollow-core-PCFs. However, the latter demonstrations were restricted to Tm emission band in order to reach the soliton self-compression effect in low-nonlinearity media. In this communication, we present a compact monolithic all-fiber source of ultrashort (35 fs) pulses emitting outside conventional lasing bands, from 1.65 to 2 μm based on Raman-induced soliton self-frequency shift (SSFS) and soliton self-compression (SSC).
关键词： ultra-short pulses,soliton self-compression,Raman-induced soliton self-frequency shift,solitonic self-compression,short-wavelength infrared
更新于2025-09-11 14:15:04
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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) - Short-Wavelength, Near-Diffraction-Limited Beam, 792 nm Cladding Pumped Efficient Thulium-Doped Fiber Laser in a Power-Scalable Fiber Design
摘要： Thulium-doped fiber lasers (TDFLs) offer a broad 3F4 → 3H6 emission band ~1600-2200 nm. Thanks to “two-for-one” cross-relaxation process in TDFLs, that enables to achieve output power > 1 kW at ~2045 nm with 0.79-μm cladding-pumping. Efficient cross-relaxation requires high Tm-concentration ( > 3wt%). This results in a high core refractive index (thus higher V-number) that degrades the beam quality. It also increases the thermal load per unit length, although this can be reduced by a large cladding-to-core area ratio that increases the absorption length of the fiber. A long fiber also shifts the emission to long wavelengths with more signal re-absorption. For short-wavelength emission the re-absorption must be reduced in some other way, which also ensures adequate total pump absorption. Simplest technique is to reduce the area ratio, but then excessive thermal load or inefficient cross-relaxation (if the Tm-concentration is low to reduce the thermal load per unit length) hampers power-scaling.
关键词： short-wavelength,Thulium-doped fiber lasers,power-scalable fiber design,near-diffraction-limited beam
更新于2025-09-11 14:15:04
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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 Multiple Up-Converted OAM States from a Tunable Optical Vortex Parametric Laser Source
摘要： Optical vortices with a ring-shaped spatial form and an orbital angular momentum (OAM) of ?φ, arising from their helical wavefronts characterized by an azimuthal phase, exp(i?φ) (where ? is an integer termed the topological charge), have been widely exploiting a variety of research fields. These include optical trapping and manipulation, fluorescent microscopes with a high spatial resolution beyond the diffraction limit and materials processing. The aforementioned applications strongly desire wavelength-tunability and OAM-versatility to optical vortex sources. In this presentation, we report on the first generation of a signal output having multiple up-converted OAM states with ?(cid:3046) =3~5 (higher OAM than that of pump) from a nanosecond 2nd-order vortex (?(cid:3043) = 2) pumped singly resonant optical parametric oscillator (OPO) with a simple compact cavity configuration. The resulting idler exhibited negative OAM states with ?(cid:3036) =-1~-3.
关键词： Orbital angular momentum,OAM states,Wavelength-tunability,Optical vortices,Optical parametric oscillator
更新于2025-09-11 14:15:04
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P‐15.2: A Study for Easy and Quick White Balance Adjustment in Laser Display Production
摘要： White balance adjustment is crucially important but time-consuming work in display production. In this paper, we point out challenges in white balance adjustment process and discuss how they can be resolved using the Discrete Centroid Wavelength Method, which was newly developed for laser-display measurement.
关键词： Chromaticity,Tristimulus Values,Colorimetry,Laser,Optical Power,Laser Display,White Balance Adjustment,Centroid Wavelength,Photometric Quantity,Photometry,Power Meter
更新于2025-09-11 14:15:04
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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) - Power Dependent Noise Performance of fs Supercontinuum Generation in Normal Dispersion Fibers with a Long Zero-Dispersion Wavelength
摘要： One of the requirements for generating a low noise supercontinuum (SC) in a normal dispersion fiber using a femtosecond (fs) pump is to have the minimum absolute dispersion wavelength to be close to zero in order to avoid parametric Raman noise. SC generation in all-normal dispersion fibers can under certain requirements provide a highly coherent spectrum, which is of key importance to a large range of imaging and spectroscopy applications. Key requirements to avoid Raman noise and noise from polarization mode instability (PMI) is to have a sufficiently low peak power (P0), short pulse length (T0), short fiber length, and high fiber birefringence. Silica microstructured fibers (MSFs) pumped with 1550 nm fs lasers is an attractive platform to generate a low noise SC due to their technological maturity. We therefore fabricated a low-loss silica MSF (using 2 cladding sections with different hole sizes) with weak dispersion at 1500 nm and experimentally studied SC generation at low peak powers using a 1550 nm, 125 fs pump. The group velocity dispersion (β2) profile of the fiber is shown in Fig. 1(a). Since the dispersion at the pump is weak, a low P0 can be used to generate a broad SC. A further advantage of using low peak powers is the possibility of avoiding PMI. The requirement of weak dispersion at 1550 nm leads to a fiber design with a zero dispersion wavelength (ZDW) at 1.8 μm. The SC generated with up to P0 =9 kW does not cross the ZDW and has low relative intensity noise (RIN) as was demonstrated numerically and experimentally [see Fig. 1(b)]. To study the effect of higher input power, where the SC crosses into the anomalous dispersion region (ADR), we performed numerical modelling, taking into account both quantum noise and laser amplitude noise by adding 1% fluctuation in P0 with constant P0T0. At P0 =45 kW the broadening is initially from self-phase modulation and optical wave breaking in the normal dispersion region (NDR), but later the SC broadens into the ADR and develops into solitons. These solitons generate trapped dispersive waves that are very noisy and move through the low-noise spectrum in the NDR [see Fig. 1(c+d)]. Our results using the novel MSF for low-noise normal dispersion SC generation at 1550 nm, demonstrate that a long wavelength ZDW can be tolerated, as long as the peak power is sufficiently low to avoid power crossing into the ADR.
关键词： zero-dispersion wavelength,femtosecond pump,low noise,normal dispersion fibers,supercontinuum generation
更新于2025-09-11 14:15:04