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J. Chen A. Hangauer R. Strzoda M.-C. Amann 《Applied physics. B, Lasers and optics》2010,100(2):331-339
In this paper, an improved signal processing method is given, aiming at a sensitivity improvement of the tunable diode laser spectroscopy based gas concentration measurement. The gas absorption spectrum is probed with an optimum wavelength scanning function which enables a more efficient curve fit than for traditional linear wavelength scanning. The wavelength scanning function is determined to be optimum, in the sense that the variance of the estimated concentration noise is minimized. This optimum scanning function depends on the signal model used in curve fitting. Several models including interfering gas spectra and etalon fringes are examined. Compared to the gas absorption spectrum recorded by ramping the wavelength linearly, the optimum spectrum waveforms have a cascade structure, which means that the optimum scanning preferably samples important points of the spectrum. The new method theoretically enables a factor of ~2 improvement on detection sensitivity of the estimated concentration. Furthermore, direct spectroscopy is superior to second harmonic detection, because the concentration noise can be an additional factor of ~2 lower. 相似文献
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利用简单的外腔,实现了具有宽发光区的商用半导体二极管激光列阵(DLA)的外腔锁相。光谱测量表明,DLA的谱宽由自由运行时的1.9 nm压缩到了0.16 nm,峰值波长由803.8 nm调整到805.5 nm;实测远场光瓣间角距等于1.6 mrad,即波长与发光单元间距之比,表明列阵运行在基超模(或最高阶超模);峰谷结构调制度大于0.8。观察表明,外腔长度在1/10~1/6泰伯距离内变化时,锁相均能实现。实验事实表明锁相是交叉注入锁定的结果。利用半导体激光注入锁定理论,定性分析了外腔DLA由自由振荡向锁相过渡的过程,预言了锁相场波长应出现在自由运行DLA光谱长波端,实验也证实了这一事实。 相似文献
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A tunable single-mode laser is obtained by using a weakly coupled cavity structure involved in a coaxially packaged Fabry-Perot laser diode. The cleaved end facet of the coupling fiber becomes an optical reflector and forms an external cavity with a laser facet. The single-mode oscillation condition is controlled and stabilized by tuning the operating temperature. The tuning range is about 10 nm with the side-mode suppression ratio of more than 27 dB when the temperature changes from 11.5 degrees C to 25 degrees C. Direct modulation characteristics were investigated, and our results show that a shorter external cavity can bear deeper modulation depth. 相似文献
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从理论和实验上对二极管激光阵列在Talbot外腔中的锁相进行了研究。在同相模和异相模近场分布的基础上,利用1维情况下的菲涅耳衍射公式计算了其远场分布。根据同相模和异相模在Talbot腔中的分布特性,采用1/2 Talbot腔并将外腔镜倾斜一个角度a的方法既能选择同相模,又能使模式的功率损耗最小。二极管激光阵列芯片采用CD金刚石材料,“三明治”结构对其进行封装,明显地减小了阵列的“smile”效应。在实验中实现了二极管激光阵列同相模的锁相输出,远场单瓣模的半高全宽为0.11 mm。 相似文献
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Dual-wavelength bandwidth-narrowed output of a high-power diode laser using a simple external cavity
Using an external cavity consisting of an etalon and a mirror, dual-wavelength operation of a high-power broad-area multi-stripe diode laser is achieved. The reflection of the etalon is used as the output beam of the system. The free-running bandwidth of the laser diode is about 2.0 nm. At dual-wavelength operation, the bandwidth of each wavelength component is narrowed to about 0.07 nm, while the space between them is 1.65 nm, determined by the FSR of the etalon. We obtain an available dual-wavelength output power of 2.0 W at the drive current of 6.5 A. The power ratio of the components at two different wavelengths can be changed by changing the temperature of the diode laser. To tune the wavelength of the dual-wavelength output, the temperature of the laser diode and the tilt angle of the etalon are changed simultaneously PACS 42.55.Px; 42.60.Fc; 42.60.Da 相似文献
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The outputs from an 11-element, linear diode laser array with broad stripes have been beam combined into a single beam with a beam quality of ~20x diffraction limited in the plane of the junction. This beam combining was achieved by use of a common external cavity containing a grating, which simultaneously forces each array element to operate at a different, but controlled, wavelength and forces the beams from all the elements to overlap and propagate in the same direction. The power in the combined beam was 50% of the output from the bare laser array. 相似文献
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从理论和实验上对二极管激光阵列在Talbot外腔中的锁相进行了研究。在同相模和异相模近场分布的基础上,利用1维情况下的菲涅耳衍射公式计算了其远场分布。根据同相模和异相模在Talbot腔中的分布特性,采用1/2 Talbot腔并将外腔镜倾斜一个角度a的方法既能选择同相模,又能使模式的功率损耗最小。二极管激光阵列芯片采用CD金刚石材料,“三明治”结构对其进行封装,明显地减小了阵列的“smile”效应。在实验中实现了二极管激光阵列同相模的锁相输出,远场单瓣模的半高全宽为0.11 mm。 相似文献
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Broad bandwidth interference filter-stabilized external cavity diode laser with narrow linewidth below 100kHz
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Interference filter-stabilized external cavity diode lasers(ECDLs) have properties of simple configurations, high stabilities, and narrow linewidths. However, the interference filter used in common ECDL designs requires an ultra-narrow bandwidth(about 0.3 nm) to achieve mode selection, that is considerably expensive and not yet available for a wide range of wavelengths. In this paper, a robust ECDL using an available broad bandwidth(about 4 nm) interference filter as the wavelength discriminator is constructed and tested. The ECDL demonstrated a narrow Lorentzian fitted linewidth of 95 kHz and a spectral purity of 2.9 MHz. The long-term frequency stability of the ECDL reaches 5.59×10~(-12). 相似文献
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Theoretical analysis on phase-locking properties of a laser diode array facing an external cavity 总被引:2,自引:0,他引:2
Dan Lu Jianguo Chen Hua Yang Haibo Chen Xiaodong Lin Song Gao 《Optics & Laser Technology》2006,38(7):516-522
External coupling model has been used to describe the output field of a laser diode array (LDA) phase-locked with an external cavity. The analytical solution for the coupling matrix equation of the phase-locked system has been obtained. The dependencies of the threshold gain, gj of the system mode on the residue reflection of the front facet, rf and round trip external cavity lengths, L have been discussed. The working lengths of the external cavity for stably phase-locking the LDA of different residual reflectivities have been calculated. 相似文献
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The external cavity feedback of a broad-area laser diode is investigated. In Fourier optic methods, the inserted prism in an external cavity can be interpreted as a spatial filter in the Fourier plane of the laser diode. The transverse mode can be selected by changing the position of the filter. As the result of a self-consistency theoretical analysis, the output beam of the external cavity has a single-lobed far-field profile. It agrees well with the experiment result. The beam times-diffraction-limit-factor M2 is measured to be 1.16. 相似文献
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给出了描述半导体激光器列阵(LDA)稳定状态的非线性方程组。对非线性方程组进行了分析,研究了LDA在稳态运行时的特性。分别分析了LDA在同相模运行和反相模运行时,载流子浓度、振荡频率以及光子数密度与自由运行时相比较所发生的变化。 相似文献