- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Optimization of Transmitter-Side Signal Rotations in the Presence of Laser Phase Noise
摘要： In this paper, we present a 1050-nm electrically pumped microelectromechanically tunable vertical cavity surface-emitting laser (MEMS-VCSEL) with a record dynamic tuning bandwidth of 63.8 nm, suitable for swept-source optical coherence tomography (SS-OCT) imaging. These devices provide reduced cost and complexity relative to previously demonstrated optically pumped devices by obviating the need for a pump laser and associated hardware. We demonstrate ophthalmic SS-OCT imaging with the electrically-pumped MEMS-VCSEL at a 400 kHz axial scan rate for wide-field imaging of the in vivo human retina over a 12 mm × 12 mm field and for OCT angiography of the macula over 6 mm × 6 mm and 3 mm × 3 mm fields to show retinal vasculature and capillary structure near the fovea. These results demonstrate the feasibility of electrically pumped MEMS-VCSELs in ophthalmic instrumentation, the largest clinical application of OCT. In addition, we estimate that the 3 dB coherence length in air is 225 ± 51 m, far greater than required for ophthalmic SS-OCT and suggestive of other distance ranging applications.
关键词： Medical imaging,tunable lasers,optical coherence tomography,micro and nano opto-electromechanical systems (MOEMS),semiconductor lasers
更新于2025-09-23 15:21:01
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Flattop output extra-wide tuning range tunable laser design technique
摘要： The laser oscillator design principle, which provides extended tunability together with a flattop output in the wide spectral range, is proposed and demonstrated on the examples of the dye laser. It is realized by using an high-reflecting (HR) moving intracavity mirror (scraper) with the sharp edge partially overlapping the laser radiation in the high-Q cavity and extracting it out. The technique provides the output laser beam with M2 < 1.2 and can be applied to any type of lasers operating from the far-IR to the VUV spectral ranges. Besides, wide-band HR cavity mirrors are only used, and there are no special demands to the material of the mirror substrate.
关键词： laser efficiency,output coupler optimization,tunable lasers
更新于2025-09-23 15:19:57
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High-Power, Narrow-Linewidth, Miniaturized Silicon Photonic Tunable Laser with Accurate Frequency Control
摘要： We have demonstrated a hybrid-integrated silicon photonic (SiPh) tunable laser in a miniaturized package, suitable for coherent modules in small form factors such as OSFP and QSFP-DD. Through the integration of an in-house-designed high-power semiconductor optical amplifier (SOA), the developed SiPh laser has achieved a record-high output power of 21.5 dBm across the C-band. Also, this laser exhibits narrow linewidths down to 60 kHz, SMSR larger than 50 dB, low relative intensity noise below -150 dB/Hz, and a broad tuning range of 65 nm. These performance parameters are preferable for 400 Gb/s and beyond coherent communications using advanced high-order modulation formats. Moreover, an on-chip integrated sensor technology was developed for accurate laser frequency control. We have achieved 1 GHz frequency stability of SiPh laser against SOA current changes or package temperature variations between 10 oC and 80 oC. We further show the feasibility of this developed SiPh laser for 64 Gbaud, 16/64 QAM coherent transmission by integrating with an in-house InP-PLC hybrid coherent optical subassembly (COSA).
关键词： Wavelength tunable lasers,Silicon photonics,Hybrid integration,Photonic integrated circuits,Semiconductor optical amplifiers
更新于2025-09-19 17:13:59
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Monolithic Tunable InAs/InP Broadband Quantum-Dash Laser
摘要： A two-sectioned quantum dash laser structure based on an InAs/InP chirped active region medium is investigated as a monolithic broadband tunable laser. A thorough parametric analysis on the effect of three tuning parameters (viz. injection current, cavity length, absorber-to-device length ratio) on the optical power-injection current (L-I) and spectral characteristics, particularly wavelength tunability and bandwidth broadening, is performed. A total emission wavelength tunability of ～20 nm is demonstrated in the mid-L-band (～1600 to ～1620 nm) window and ～2 times enhancement in the 3dB bandwidth. Furthermore, optical bistability in the two-sectioned InAs/InP quantum-dash laser device is observed at near room temperature in the form of L-I curve hysteresis. Further investigation displayed a direct relation between the absorber length and the hysteresis loop width with a maximum value of ～40 mA is demonstrated; a potential platform in fast optical switching and modulation applications. Finally, the two-sectioned structure is also proposed and investigated as a monolithic two-segment contact spectrum shaper to manipulate the lasing spectrum pro?les to attain ?at tops and effectively increase the spectrum 3dB bandwidth. As such, a maximum 3dB bandwidth was able to be pushed up to ～20 nm from ～7 nm by proper tuning of the current density distribution across the two segments of the device.
关键词： optical bistability,tunable lasers,L-band lasers,Broadband lasers,quantum-dash lasers,multi-segment lasers,quantum-dot lasers,two-section lasers
更新于2025-09-16 10:30:52
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A novel repetition rate adjustable SBS-based Q-switched fiber laser
摘要： We experimentally demonstrated a novel repetition rate adjustable SBS-based Q-switched fiber laser. An inserted Fabry-Perot interferometer formed by two non-contact end faces of two FC/PC fiber connectors was inserted to help the system stabilize the random output of SBS-based Q-switching. By mechanically fine-tuning the length of the inserted Fabry-Perot interferometer, a linear and continuous repetition rate adjustment under a fixed pump power was achieved. This method paves a new way for the indirect control of repetition rate in SBS-based Q-switched fiber lasers. It is also found out that higher pump power allows wider adjustment range. At 600 mW pumping which is highest pump power of the source, the repetition rate almost tripled from 11.22 kHz to 32.06 kHz only by varying the length of FP cavity in less than 3 μm. In the meantime, the variation of pulse width, output power and single pulse energy were recorded and analyzed under different fixed pump powers. Although the adjusting range of repetition rate is not very wide but the tuning of repetition rate due to such a small length changing is unique and valuable. This original repetition rate control technique has great potential in areas like environment sensing and material detections.
关键词： tunable lasers,fiber lasers,Q-switched lasers
更新于2025-09-16 10:30:52
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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Graphene-like Si <sub/>3</sub> N <sub/>3</sub> and Si <sub/>3</sub> N <sub/>4</sub> Nanolayers on Silicon Surface
摘要： In this paper, we present a 1050-nm electrically pumped microelectromechanically tunable vertical cavity surface-emitting laser (MEMS-VCSEL) with a record dynamic tuning bandwidth of 63.8 nm, suitable for swept-source optical coherence tomography (SS-OCT) imaging. These devices provide reduced cost and complexity relative to previously demonstrated optically pumped devices by obviating the need for a pump laser and associated hardware. We demonstrate ophthalmic SS-OCT imaging with the electrically-pumped MEMS-VCSEL at a 400 kHz axial scan rate for wide-field imaging of the in vivo human retina over a 12 mm × 12 mm field and for OCT angiography of the macula over 6 mm × 6 mm and 3 mm × 3 mm fields to show retinal vasculature and capillary structure near the fovea. These results demonstrate the feasibility of electrically pumped MEMS-VCSELs in ophthalmic instrumentation, the largest clinical application of OCT. In addition, we estimate that the 3 dB coherence length in air is 225 ± 51 m, far greater than required for ophthalmic SS-OCT and suggestive of other distance ranging applications.
关键词： Medical imaging,tunable lasers,optical coherence tomography,micro and nano opto-electromechanical systems (MOEMS),semiconductor lasers
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) - Twin tunable laser system with wavelength calibration for Tera-Hertz spectrometer
摘要： available Tera-Hertz system, its laser tuning is realized by changing the operation temperature tuned. However, temperature tuning requires a self-contained temperature control device, which causes a low tuning speed and the tuning accuracy is also difficult to be guaranteed. In this study, we proposed a laser beat system by current tuning, not by temperature, and applied in a Tera-Hertz spectrometer. The continuous Tera-Hertz spectrum can be generated by using two sets of feedback loops to control the current of twin tunable laser. Relatively, the current tuning is quicker and more accurate.
关键词： DBR tunable lasers,wavelength calibration,Tera-Hertz spectrometer
更新于2025-09-16 10:30:52
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Experimental Demonstration of π Equivalent Phase-Shifted SBG Laser with Controlled Distributed Phase Shift
摘要： We designed and fabricated a π equivalent phase-shifted sampled Bragg grating (SBG) semiconductor laser with a controlled distributed phase shift. The phase shift is equivalently realized with reconstruction-equivalent-chirp (REC) technique. The laser is divided into three sections with the same length. By injecting different currents into the side and middle sections, a distributed phase shift can be introduced. The lasing wavelength can be continuously tuned by the injection currents. In our experiment, when the total current keeps 130 mA, the lasing wavelength can be continuously tuned by 1.2 nm. During the tuning, the side mode suppression ratio keeps above 40 dB and the output power varies only 1.3 dB. Therefore, the proposed method provides an alternative solution for the multiwavelength laser arrays in dense wavelength-division multiplexing (DWDM) systems.
关键词： Fibre Gratings,Semiconductor Lasers,Tunable Lasers
更新于2025-09-12 10:27:22
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Laser absorption spectroscopy of rare and doubly-substituted carbon dioxide isotopologues
摘要： Unambiguous detection of the clumped carbon dioxide isotopologue 13C16O18O with isotope ratio mass spectrometry is difficult due to isobaric interference on m/z = 47. We present an analytical technique based on direct absorption laser spectroscopy for precise, direct and simultaneous detection of all isotopologues involved in the isotope exchange reaction 12C16O2 + 13C16O18O ? 12C16O18O +13C16O2 and of 12C16O17O. The achieved precision of 2×10-5 for the 13C16O18O/13C16O2 and 12C16O18O/12C16O2 isotopologue ratios allows to determine the equilibrium constant K of the isotope exchange reaction with an external reproducibility of better than 2×10-5 (1σ) after 9 reference-sample comparisons. Each comparison requires 7 minutes. The isotopic composition of the pure gas can be simultaneously analyzed with a precision of 0.05‰ (1σ) for δ13C and δ18O, and 0.15‰ (1σ) for δ17O. The instrument deploys two interband cascade lasers (ICL) with center wavelengths of 4.3 μm and 4.4 μm. A custom-built optical cell has been designed for single pass and multi pass optical paths (pathlength ratio 1:100); it allows simultaneous detection of rare and abundant isotopologues. The setup is capable to analyze pure CO2 samples of ～100 μmol.
关键词： clumped isotope analysis,mid-IR lasers,tunable lasers,doubly substituted isotopologues,carbon dioxide,laser spectroscopy,laser absorption
更新于2025-09-12 10:27:22
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Low-cost multimode diode-pumped Tm:YAG and Tm:LuAG lasers
摘要： We report a continuous-wave operation of Tm:YAG and Tm:LuAG lasers pumped with a low-cost, multimode AlGaAs laser diode. First, the lifetime and the absorbance behavior of 5 mm, 6% Tm 3+ -doped YAG and LuAG crystals were thoroughly investigated. A low-cost multimode 3W laser diode at 781 nm was then used as a pump source for the Tm 3+ -doped laser systems. Using three different output couplers, up to 636 mW of output power was obtained from Tm:YAG laser, with a slope efficiency of 29% at 2017 nm. The maximum output power was 637 mW in the Tm:LuAG laser, with a slope efficiency of 28% at 2023 nm. The lasing performances showed a decreasing slope efficiency with an increasing level of output coupling, which leads to a high upconversion. Furthermore, using a birefringent filter in the resonators, the laser outputs were tuned from 1942 to 2086 nm in the Tm:YAG resonator and from 1931 to 2107 nm in the Tm:LuAG case.
关键词： diode-pumped lasers,infrared lasers,Tm:LuAG laser,Tm:YAG laser,tunable lasers,solid-state lasers,Lasers
更新于2025-09-11 14:15:04