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1.
We study the effects of the semiconductor laser noise on the generated beat signal, in Coherent Optical Domain Reflectometry device. By using a general laser noise analytical model, based on Volterra non-linear treatment of laser rate equations, we find a novel general expression of the beat photocurrent. We show that the coherence and the incoherence cases are observed for a different delay time intervals than the ones known in literature. We show that the coherence domain corresponds to a delay time lower than the half of the laser coherence time τ0<1/2τc, and the incoherence domain corresponds for τ0>2τc. An original shape of the beat signal autocorrelation function affected by the laser noises is obtained. 相似文献
2.
A method for recording fan-shaped transmitting phase holographic gratings that ensure tuning of the wavelength of emission
for a DFB (distributed-feedback) dye laser is presented. Traditional optical elements are used in the scheme of grating recording.
A change in the degree of grating fanning is reached here without replacement of gratings. The possibility of obtaining frequency-tuned
emission by means of the fan-shaped gratings created is demonstrated experimentally.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 1, pp. 48–51, January–February, 2000. 相似文献
3.
Han Yang XiangSheng Liu Jian Du Wei Sun DeHui Li MaoBin Yi GuoTong Du 《Optics & Laser Technology》2005,37(1):55-60
Optical pulse generated by directly modulated distributed feedback (DFB) laser and external electro-absorption modulator (EAM) in virtue of the method of fringe-resolved second-harmonic generation correlation was measured. Without the pulse's shape being assumed, through the method of iterative reconstruct interference signal, the waveform and phase of the pulse was reconstructed. The full-wave at half-maximum (FWHM) of the pulse generated by EAM under the microwave modulation of 2.5 GHz is 30.8 ps, whose shape is close to that of the sech2-type pulse. The FWHM of the pulse generated by DFB laser is 18.3 ps, whose shape is close to that of the Lorenz-type pulse. And the original chirping of EAM is smaller than that of DFB laser. 相似文献
4.
5.
Q. Zhao J.Q. Pan J. Zhang B.X. Li F. Zhou B.J. Wang L.F. Wang J. Bian L.J. Zhao W. Wang 《Optics Communications》2006,260(2):666-669
A strained InGaAsP-InP multiple-quantum-well DFB laser monolithically integrated with electroabsorption modulator by ultra-low-pressure (22 mbar) selective-area-growth is presented. The integrated chip exhibits superior characteristics, such as low threshold current of 19 mA, single-mode operation around 1550 nm range with side-mode suppression ratio over 40 dB, and larger than 16 dB extinction ratio when coupled into a single-mode fiber. More than 10 GHz modulation bandwidth is also achieved. After packaged in a compact module, the device successfully performs 10-Gb/s NRZ transmission experiments through 53.3 km of standard fiber with 8.7 dB dynamic extinction ratio. A receiver sensitivity of −18.9 dBm at bit-error-rate of 10−10 is confirmed. 相似文献
6.
从DFB型激光二极管调谐机理出发,提出了电流-温度调谐特性的解析模型,通过实验测量结果辨识出模型参数,将模型应用于四个不同厂家的DFB型二极管激光器,得到激光器电流-温度调谐的解析模型;将模型预测值与实验测量值比较,相关系数均在0.9999以上.同时,利用CO2气体的多个吸收谱线测量激光的波长,验证了解析模型的预测波长值,与HITRAN谱库中CO2气体吸收波长的误差在3 pm内.解析模型能够精确预测激光器在快速调谐过程中的瞬态输出波长,其精度能够满足光谱分析、光
关键词:
DFB激光二极管
调谐机理
解析模型
电流调谐和温度调谐 相似文献
7.
A new method of analyzing the chirp characteristics of directly modulated lasers and integrated laser-modulators is presented in this paper. Phase-circuit has been introduced into the circuit model of distributed feedback (DFB) lasers in the analysis. Therefore, the chirp characteristics of the device can be obtained by simulating the modified circuit model. The simulation results agree well with the published data. Furthermore, this modified model is combined with the circuit model of electroabsorption (EA) modulators to simulate the chirp characteristics of the monolithic integration of a DFB laser and an EA modulator. The simulation is focused on the dependence of the frequency chirp of the integrated device on the isolation resistance between laser and modulator. Much lower chirp can be seen in the integrated lightwave source compared to the directly modulated laser. 相似文献
8.
9.
An apodized DFB semiconductor laser based on reconstruction-equivalent-chirp (REC) technology is proposed and investigated numerically. By changing the duty cycle of the sampling period, the magnitude of the equivalent index modulation is varied. Thus the equivalent apodization is introduced instead of an actual apodization. This novel DFB structure is advantageous in that it can enlarge the threshold gain difference and improve the mode stability compared with the conventional DFB laser. Moreover, the structure can be easily fabricated by standard holographic technology instead of high cost Electron-beam lithography. 相似文献
10.
We Propose a set of single mode rate equations for multi-section distributed feedback(DFB) lasers. On the basis of the rate equations, the self-pulsation in the two-section DFB lasers with asymmetrical injection current was explained. It was found that the dynamic distribution of the power in two sections play key role in the self-pulsation running. 相似文献
11.
Characterization of semiconductor laser frequency chirp based on signal distortion in dispersive optical fiber 总被引:1,自引:0,他引:1
P. Krehlik 《Opto-Electronics Review》2006,14(2):119-124
In the paper, the simple method of laser chirp parameters estimation is presented. It is based on measuring time-domain distortions
of chirped signal transmitted through dispersive fiber and finding laser chirp parameters by matching measured distortions
to calculated ones. Experiments undertaken with 1.55 μm telecommunication grade distributed feedback (DFB) lasers and standard
single-mode fiber are described, together with some practical remarks on measurement setup and main conclusions. 相似文献
12.
K. N. Korostik 《Journal of Applied Spectroscopy》1997,64(1):45-49
The effect of the shape of the excitation pulses on the magnitude of the frequency chirp in an injection laser is investigated.
It is established that as the degree of rectangularity of the pulses becomes higher, the frequency chirp increases. Simultaneous
consideration of the effect of residual charge in the active region of the laser, the delay of stimulated radiation, and the
frequency chirp indicates that in the case of high-velocity code modulation of an injection laser, in the latter an irregular
frequency chirp appears that can exert a noticeable influence on the distortion of code trains of pulses having a super-Gaussian
shape, when they propagate in media with a dispersion of 100 p.s./nm/km and above.
Belarusian State University, 4, F. Skorina Ave., Minsk, 220050, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 64, No. 1, pp. 45–49, January–February, 1997. 相似文献
13.
本文报导应用激光扫描,在Φ5mm至由60mm的外径上,实现±0.02mm动态测量精度的研究结果。文中对研究原理及精度分析作出简明阐述。 相似文献
14.
基于双光纤光路等光频重采样原理,提出了一种距离精度的评定方法.通过推导噪声背景下等光频重采样信号中距离参量的克拉美-罗下边界,得到了影响系统测距精度的两个重要因素:信噪比和扫描带宽,并进行了实验验证.实验表明,该评价方法并不会受到任何距离估算方法的影响,根据此方法可以选择一个最优的距离估算方法.通过对两个影响精度的因素进行仿真分析可知,在扫描带宽为2.2 nm时,若将测量光路的信噪比提升至70 dB以上,系统可获得低于10μm的测距精度.该精度评定方法可为后续改善调频连续波测距系统性能提供理论参考. 相似文献
15.
对单模激光增益模型的光强方程加入调频信号,用线性化近似方法计算了以δ函数形式关联的两白噪声驱动下光强的输出功率谱及信噪比. 结果表明,信噪比随抽运噪声和量子噪声强度的变化可出现典型随机共振,受调制信号振幅的影响,信噪比随载波信号频率和调制信号频率的变化出现抑制、单调上升、共振、抑制和共振等几种情况.
关键词:
抽运噪声
单模激光
随机共振
调频信号 相似文献
16.
A widely tunable dual-wavelength erbium-doped fiber ring laser operating in single longitudinal mode 总被引:1,自引:0,他引:1
A new mechanism to induce polarization hole burning effect in Er-doped fiber ring lasers is presented. By using this effect, incorporating with the counter-propagation of the two light beams, the inhomogeneous in the gain medium broadening was significantly increased, and thus a stable dual-frequency Er-doped fiber ring laser operating in single longitudinal mode and single-frequency was demonstrated. Frequency spacing was tunable from 0.47 GHz to THz. 相似文献
17.
18.
Stochastic resonance in a single-mode laser driven by frequency modulated signal and coloured noises 下载免费PDF全文
By adding frequency modulated signals to the intensity equation of
gain--noise model of the single-mode laser driven by two coloured
noises which are correlated, this paper uses the linear
approximation method to calculate the power spectrum and
signal-to-noise ratio (SNR) of the laser intensity. The results show
that the SNR appears typical stochastic resonance with the variation
of intensity of the pump noise and quantum noise. As the amplitude
of a modulated signal has effects on the SNR, it shows suppression,
monotone increasing, stochastic resonance, and multiple stochastic
resonance with the variation of the frequency of a carrier signal
and modulated signal. 相似文献
19.
大深度工作环境下,静水压会引起分布反馈式光纤激光水听器反射中心波长漂出解调系统的复用窗口,使水听器无法解调目标声压信号;不同的静水压也会引起分布反馈式光纤激光水听器灵敏度的变化,影响光纤激光水听器阵列的一致性。基于电力声类比理论,提出带静压补偿的分布反馈式光纤激光水听器探头,建立结构的声压传递函数,分析各结构参数对传递函数的影响,为分布反馈式光纤激光水听器探头频率响应平坦化设计提供理论依据。加工制作了耐静压分布反馈式光纤激光水听器样品进行测试,在0 kHz~10 kHz频率范围内声压灵敏度波动范围不大于±2.4 dB,2.3 MPa内出射激光中心波长漂移量不大于0.06 nm,对深水光纤激光水听器的研究具有指导意义。 相似文献
20.
本文对于CO_2激光外差接收单元技术之一的CO_2激光偏频锁定技术进行了研究,实现了两个自由振荡的CO_2激光器之间的差频的锁定,当采取一定措施尽量减小环境的影响后,得到了≤1 kHz(τ=10s)的频率跟踪精度,中心频率在2 MHz~20 MHz内连续可调. 相似文献