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- 摘要
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- 实验方案
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[IEEE 2019 IEEE International Instrumentation and Measurement Technology Conference (I2MTC) - Auckland, New Zealand (2019.5.20-2019.5.23)] 2019 IEEE International Instrumentation and Measurement Technology Conference (I2MTC) - High-Spatial Resolution Demodulation of Weak FBGs Based on Incoherent Optical Frequency Domain Reflectometry Using a Chaotic laser
摘要： A high-spatial resolution demodulation technique based on incoherent optical frequency domain reflectometry is proposed for distributed weak fiber Bragg grating (FBG) sensing. A single longitudinal mode, narrow linewidth light output from Distributed Feedback Laser (DFB) is modulated with a frequency swept microwave, then enter the FBGs and reflected. The reflected optical signal is transformed into electric signal by a photodiode, and then mixes with the original microwave to produce the beat frequency. We can use Fast Fourier transformation to analyze the beat frequency to modulate the location information, next control the wavelength of DFB laser to sweep in a specific range and finally obtain the wavelength information of FBGs. In order to eliminate the influence of interference between light reflected from the FBGs, chaotic signals from DFB laser with optical feedback are generated to broaden the linewidth of laser. Therefore, the spatial resolution of FBGs can be greatly improved to 10cm. and we have demonstrated the long distance demodulation nearly 500m and 10cm interval with the achieved accuracy to be 16 pm.
关键词： high-spatial resolution,chaotic laser,narrow linewidth,Incoherent Optical Frequency Domain Reflection
更新于2025-09-12 10:27:22
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Linewidth broadening factor of an interband cascade laser
摘要： This work reports the linewidth broadening factor (LBF) of a continuous-wave interband cascade laser operated both below and above threshold. Using the Hakki-Paoli method, the below-threshold LBFs around the gain peak are determined to be in the range of 1.1–1.4, where the thermal effect is carefully removed. Employing the self-mixing interferometry technique, the above-threshold LBFs are measured to be around 2.2, which do not increase with increasing pump current.
关键词： linewidth broadening factor,interband cascade laser,Hakki-Paoli method,self-mixing interferometry
更新于2025-09-12 10:27:22
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[IEEE 2019 Compound Semiconductor Week (CSW) - Nara, Japan (2019.5.19-2019.5.23)] 2019 Compound Semiconductor Week (CSW) - Thermal dependence of the emission linewidth of $1.52-\mu \mathrm{m}$ single mode InAs/InP quantum dot lasers
摘要： This paper experimentally investigates the thermal dependence of the emission linewidth of 1.52-μm single mode InAs/InP quantum dot lasers. Using a distributed feedback cavity made with symmetric antireflection coatings, a minimum linewidth of 300 kHz is unveiled. This narrow line is found rather constant with the injection current and the temperature range (293 K - 313 K). However, under certain operating conditions, a linewidth rebroadening is also observed, which may be attributed to the spectral hole burning and to the variations of the alpha-factor with the temperature and bias current. Nevertheless, these results confirm the potential of this technology for manufacturing low-phase noise oscillators for coherent optical communications.
关键词： Quantum dots,Distributed feedback lasers,spectral linewidth,rebroadening
更新于2025-09-12 10:27:22
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Influence of integrated optical Feedback on tunable Lasers
摘要： In this paper we explain how to use rate equations to describe a laser that includes integrated optical feedback. We find a relation between the threshold current, the voltage drop at the gain section, output power, linewidth, and side mode suppression ratio, and show experimental results.
关键词： Frequency Stabilization,Continuous Tuning,Gain Voltage,Wavelength Stabilization,Optical Feedback Interferometry,Tunable Laser,Output Power,Rate Equations,Laser Stability,Linewidth,Optical Feedback,Side Mode Suppression Ratio,Wavelength locking
更新于2025-09-12 10:27:22
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Strain-Related Degradation of GaN-Based Blue Laser Diodes
摘要： Degradation of GaN-based laser diodes (LDs) is studied using Electroluminescence (EL) and Transmission Electron Microscopy (TEM). The slope efficiency decrease is observed in addition to threshold current increase. Further studies on the optical loss and microstructures of the LDs indicate that the reduction of the slope efficiency is attributed to the increase of optical loss (from 14.2 cm-1 to 24.2 cm-1) and decrease of injection current efficiency induced by the defect generation around the waveguide and cladding layers. Injection current induced blue-shift of the spontaneous EL peak reduced after > 3000 hrs operation, which is ascribed to the compensation of Quantum-Confined Stark Effect (QCSE) caused by partial strain relaxation near the active region.
关键词： Spectroscopy,Degradation,Strain relaxation,Semiconductor lasers,Linewidth
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) - Time Domain Traveling Wave Model of a Hybrid Laser for Silicon Photonics Applications
摘要： Integration of lasers sources in Silicon Photonics (SiPh), realised trough different techniques, became very appealing for applications in the ever growing field of intra/inter chip data data interconnects and optical communications. We implemented a Time Domain Traveling Wave (TDTW) model based on a set of Partial Differential Equations (PDE) for the slowly varying envelope of the electric field, the medium polarization and the charge carriers density in order to describe the dynamics of a new generation of hybrid laser based on III-V Reflective Semiconductor Optical Amplifier (RSOA) and SiPh external mirror with narrow effective reflectivity bandwidth (< 10GHz) similar to that considered in [2, 3]. The effect of the SiPh mirror can be taken into account by cascading the transmission matrices associated with all its passive sections (namely spot-size-conveter, phase control sections, ring resonators etc...) and including the result in frequency dependent boundary conditions for the PDE problem. Differently from standard rate equation models for semiconductor lasers, our approch correctly reproduce the RSOA gain/refractive index dependence from frequency and carriers density that represent peculiar features of radiation-matter interaction in semiconductor media and play a fundamental role in determining the hybrid laser dynamical behaviour. After computing the TW (Traveling wave) solutions for typical narrow reflectivity bandwidth designs, we numerically showed how for realistic values of the linewidth enhancement factor α (namely α > 2) stable single frequency lasing emission not always occurs at the reflectivity peak (TW0 solution in Fig. 1), but on the red part of the SiPh mirror reflectivity resonance curve around the point of maximum reflectivity slope (TW1 solution in Fig. 1a and Fig. 1b). The fact that this point also coincides with that of minimum optical linewidth, where negative feedback regime reduces instantaneous frequencies fluctuations, and the additional numerical evidence that the interval of TW stability decreases with increasing output power indicate that phase-amplitude coupling mediated by the α-factor may be at the origin of the observed TW instability. It also follows that by a suitable tuning of a phase section in SiPh circuit it is possible to stabilize hybrid laser emission by placing a TW solution on the point of maximum reflectivity slope.
关键词： hybrid laser,Partial Differential Equations,linewidth enhancement factor,Silicon Photonics,Time Domain Traveling Wave model,Reflective Semiconductor Optical Amplifier
更新于2025-09-12 10:27:22
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Comparison of Self-Injection Locking of DFB-LD by Optical Fiber and Optical Waveguide Ring Resonators
摘要： Utilizing the frequency selection characteristic of ring resonators, self-injection-locking linewidth narrowing and frequency stabilization of distributed feedback laser diodes (DFB-LDs) can be achieved under the aid of ring resonators. In this paper, the self-injection-locking effects of a DFB-LD realized by two fiber ring resonators and an optical waveguide ring resonator are compared. The influences of the resonant peak bandwidth and transmission on linewidth narrowing are demonstrated. It is shown that the mode hopping can be significantly suppressed by employing the optical waveguide ring resonator. This is of great significance for practical applications and integration of the self-injection-locked DFB-LDs.
关键词： Self-injection locking,distributed feedback laser diode,phase noise,linewidth narrowing,mode hopping,ring resonator
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) - Towards Storage of Sub-Megahertz Single Photons in Gradient Echo Memory
摘要： Quantum repeaters are foundational to establishing the long distance quantum communication channels necessary to create a global communication network. A quantum memory capable of storing optical quantum states is an integral component of the quantum repeater. A wide variety of mechanisms for implementing an optical quantum memory have been investigated, ranging from simple optical delay lines to complicated photon echo schemes. The scheme of interest here is the gradient echo memory (GEM). GEM has been demonstrated to be one of the most efficient memory schemes to date, with up to 87% recall efficiency and up to 1ms coherence time when performed in a cold atomic ensemble of 87Rb atoms. Until now, GEM has only been investigated with weak coherent pulses as no single photon source met the demanding spectral requirements of the memory protocol. In particular, it requires sub-megahertz linewidth photons at the atomic transitions of 87Rb. A compatible source has been developed utilising cavity-enhanced spontaneous parametric downconversion (SPDC) generating photons with a bandwidth of 429 ± 10 kHz. This is, to our knowledge, the narrowest single photon bandwidth from SPDC to date. Integration with this source enables single photon storage for the first time using GEM and allows for its single photon level characteristics to finally be investigated. Single-photon quantum memory opens up the prospect of using the system as a quantum optical gate. Storing multiple single photon states simultaneously in the quantum memory can potentially give rise to photon-photon interactions due to cross phase modulation.
关键词： single photon source,gradient echo memory,quantum repeaters,sub-megahertz linewidth photons,quantum memory
更新于2025-09-11 14:15:04
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[IEEE 2018 Conference on Optoelectronic and Microelectronic Materials and Devices (COMMAD) - Perth, Australia (2018.12.9-2018.12.13)] 2018 Conference on Optoelectronic and Microelectronic Materials and Devices (COMMAD) - Isotopically Pure Silcon-28 Whispering Gallery Mode Resonators: A Host for Narrow Linewidth Spin Ensembles
摘要： Single crystal isotopically pure 28Si cylindrical Whispering Gallery (WG) mode resonators have been machined from a rod of isotopically pure crystal. Before machining, the rod was loaded into a cavity with the best Bragg confined modes exhibiting Q-factors above a million for frequencies between 10 and 15 GHz. Electron Spin Resonance spectroscopy revealed a very narrow linewidth spin transition, with g-factor of 1.995±0.008. Analysis determined an upper limit to the linewidth of 7 kHz and a concentration of less than 1011 spins/cm3 (10 parts per trillion). After machining into WG mode resonators, the measured frequencies of the fundamental mode families were used to determine the relative permittivity of the material near 4 K and 20 mK to be 11.488±0.024, with the precision limited only by the dimensional accuracy of the resonator. However, the Q-factors were degraded to below 40,000. Raman spectroscopy revealed strain induced broadening on the radial surface of the crystal as a result of the machining. After an acid clean and etch, followed by annealing, the surface damage was repaired. Subsequently, high Q-factors were also restored. The next step will be to purposefully implant ions to try and realise narrow linewidth spin ensembles with clock transitions, which will couple to high-Q WG modes inside the crystal.
关键词： Narrow linewidth spin ensembles,Isotopically pure silicon-28,Q-factors,Electron Spin Resonance spectroscopy,Whispering Gallery Mode Resonators
更新于2025-09-11 14:15:04
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[IEEE 2019 Joint Conference of the IEEE International Frequency Control Symposium anEuropean Frequency and Time Forum (EFTF/IFC) - Orlando, FL, USA (2019.4.14-2019.4.18)] 2019 Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum (EFTF/IFC) - Earthquakes detection with optical fibers
摘要： The existing optical fiber network for telecommunication, together with coherent laser interferometry techniques such as narrow-linewidth lasers and heterodyne detection, is proposed as a tool for the detection of earthquakes. Using this infrastructure, we were able to detect several earthquakes, with moment magnitude as small as 3.4 and distances to the epicenter ranging between 25 and 18500 km. Such capability is extremely relevant for the detection of earthquakes in the seas and oceans, which are today poorly covered by bulk seismometers. We propose this technique as complementary to traditional detection and show how it can be established on the existing fiber network.
关键词： optical fiber link,frequency metrology,narrow-linewidth lasers,heterodyne detection,laser interferometry
更新于2025-09-11 14:15:04