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Compact dual-gas sensor for simultaneous measurement of atmospheric methane, and water vapor using a 3.38?μm antimonide-distributed feedback laser diode
摘要： A simple, compact sensor involving a continuous-wave 3.38 mm distributed feedback laser in combination with a novel compact dense-pattern multipass cell was demonstrated for simultaneous measurement of atmospheric methane and water vapor. The calibration-free direct absorption spectroscopy approach was adopted for data generation and processing. Allan deviation analysis indicates that minimum detection limits (1s) of 11.0 ppb for CH4 and 100 ppm for H2O were achieved with a 1-s integration time at an optimum pressure of 50 Torr. Atmospheric environmental mixing ratios of these two gases were recorded and analyzed. This newly developed mid-infrared dual-gas sensor is very suitable for trace gas sensing in weight-limited unmanned aerial vehicle- or balloon-embedded field observations.
关键词： Multipass cell,Laser sensors,Water vapor,Distributed feedback laser,Laser absorption spectroscopy,Methane
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - St. Petersburg, Russia (2019.10.17-2019.10.18)] 2019 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - Distortion Analysis of Interferometric Signal with Auxiliary Emission Modulation in Semiconductor Laser
摘要： The results of analysis of distortion of interferometric signal of a semiconductor laser with the current modulation are presented. The mathematical model of the interferometric signal was refined based on experimental data. Measurements were performed for harmonic and triangular auxiliary modulation, and the effect of laser thermal stabilization on the modulation of the interferometric signal was studied.
关键词： phase modulation,external cavity laser,thermal stabilization,distributed feedback laser,distortion of interferometric signal
更新于2025-09-16 10:30:52
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Slot-Waveguide Silicon Nitride Organic Hybrid Distributed Feedback Laser
摘要： one of the major barriers for a widespread commercial uptake of silicon nitride photonic integrated circuits for cost-sensitive applications is the lack of low-cost monolithically integrated laser light sources directly emitting into single-mode waveguides. In this work, we demonstrate an optically pumped organic solid-state slot-waveguide distributed feedback laser designed for a silicon nitride organic hybrid photonic platform. Pulsed optical excitation of the gain medium is achieved by a 450 nm laser diode. the optical feedback for lasing is based on a second-order laterally coupled Bragg grating with a slot-waveguide core. Optimized material gain properties of the organic dye together with the increased modal gain of the laser mode arising from the improved overlap of the slot-waveguide geometry with the gain material enable single-mode lasing at a wavelength of 600 nm. The straightforward integration and operation with a blue laser diode leads to a cost-effective coherent light source for photonic integrated devices.
关键词： photonic integrated circuits,silicon nitride,slot-waveguide,distributed feedback laser,organic hybrid
更新于2025-09-12 10:27:22
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The effect of detuned wavelength in the dynamic performance of distributed feedback lasers operating at O band and C band
摘要： A comparison is presented between the experimental dynamic behavior of detuned AlInGaAs ridge waveguide distributed feedback lasers operating at O band and C band at two different temperatures. The nominal center wavelengths at 25(cid:1)C for the set of devices studied were 1270, 1310, and 1550 nm. Preliminary static characterization of the samples showed consistent trends between wavelength detuning, characteristic temperature, and power output. For all set of samples, the characteristic temperature was substantially higher for the samples detuned to longer wavelengths (red) at room temperature. At the temperature of 85(cid:1)C, a higher power efficiency was observed for those samples that thermally shifted nearer the peak optical gain. Resonance frequencies were extracted at 25(cid:1)C and 85(cid:1)C by means of electro-optical transmission measurements and relative intensity noise measurements. The extracted values confirmed that at room temperature the samples detuned to shorter wavelengths (blue) showed the highest modulation efficiencies. At the temperature of 85(cid:1)C, however, the wavelength and optical gain thermal shift makes those same samples to have the lowest resonant frequencies. The dynamic trends over temperature were clearer for the O band set of samples, while the detuning had a less pronounced effect at C band. The range of maximum resonance frequencies studied was from 12 to 14 GHz, which makes the devices suitable for uncooled communication applications at multi-gigabit data rates.
关键词： dynamics,wavelength detuning,distributed feedback laser
更新于2025-09-12 10:27:22
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Influence of structural parameters on organic semiconducting polymer lasers with an external holographic grating as feedback layer
摘要： We report on the fabrication and characterization of an organic distributed feedback laser excited from a semiconducting polymer gain layer, poly(2-methoxy-5-(20-ethyl-hexyloxy)-p-phenyl-envinylene) (MEH-PPV). A holographic polymer dispersed liquid crystal grating is fabricated on top of the homogeneous MEH-PPV layer as an external cavity. We established a model to calculate the con?nement factor Γ. With the change of laser structural parameters (the refractive index of the grating layer, the ?lm thickness of the MEH-PPV layer, etc.), the con?nement factor Γ changes accordingly. It was found that a single longitudinal lasing mode could be observed only when the con?nement factor Γ was in a speci?c range. Choosing a reasonable thickness of gain ?lm and prepolymer with higher refractive index can obtain a lower threshold emission laser.
关键词： organic distributed feedback laser,lasing mode,semiconducting polymer,holographic polymer dispersed liquid crystal grating,con?nement factor
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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Influence of Light Coupling Configuration and Alignment on the Stability of HWG-Based Gas Sensor System for Real-Time Detection of Exhaled Carbon Dioxide
摘要： A mid-infrared tunable diode laser absorption spectroscopy (TDLAS) gas sensor based on hollow waveguide (HWG) gas cell for real-time exhaled carbon dioxide (eCO2) detection is reported. A 2.73 μm distributed feedback (DFB) laser was used to target a strong CO2 absorption line, and wavelength modulation spectroscopy (WMS) with the second harmonic (WMS-2 f ) was used to retrieve the CO2 concentration with high sensitivity. The influence of different parameters, including coupling configuration of HWG, laser-to-HWG and HWG-to-detector coupling alignment on the stability of the HWG sensor is systematically studied. The HWG eCO2 sensor showed a fast response time of 2.7s, detection limit of 17 ppmv, and measurement precision of 20.9 ppmv with a 0.54 s temporal resolution. The eCO2 concentrations changed in breath cycles were measured in real time. The Allan variance indicated that the detection limit can reach 1.7 ppmv, corresponding to a detection sensitivity of 1.3×10?8 cm?1 Hz?1/2, as the integration time increases to 26 s. This work demonstrates the performance characteristics and merits of HWG eCO2 sensor for exhaled breath analysis and potential detection for other exhaled gases.
关键词： hollow waveguide,distributed feedback laser,carbon dioxide,Tunable diode laser absorption spectroscopy
更新于2025-09-11 14:15:04