掺铥光纤激光器设计与仿真

掺铥光纤激光器工作波段在人眼安全波段,凭借其结构紧凑、灵活性高、散热性强、光束质量好、量子效率高等优势得到了越来越多的关注。本研究设计1700~1800 nm波段的光纤激光器,将以泵浦光中心波长786 nm,去激发光纤激光器中心波长1740 nm。其中光纤长度设置为5 m。实验结果表明:泵浦光功率大于5 W时会产生激光,小于5 W时不会产生激光。通过实验可知,泵浦光功率会随光纤长度增长而减小,信号光功率会随光纤长度增大而增大。

光纤参量放大器增益特性的理论与仿真分析

为了优化光纤参量放大器的增益特性,利用理论分析,对FOPA在不同光纤长度、不同泵浦光功率及不同光纤非线性系数下的增益与带宽特性进行了比较与分析。结果表明:使用较长的高非线性光纤、较大的泵浦光、或较大的非线性系数,均可提高FOPA的增益,增益带宽也可随着泵浦光功率和非线性系数的增大而增大。此外,利用仿真模拟对理论分析结果进行了验证。虽然,仿真结果与理论分析结果间略有偏差,但仿真结果依然较好的验证了理论结果的正确性与可行性。

掺镱双包层光纤激光器的输出特性

运用速率方程组,推导了掺镱双包层光纤激光器的阈值泵浦光功率以及输出光功率的解析解。在研究阈值泵浦光功率的情况中,考虑了光纤中自发辐射的存在。对腔镜反射率和光纤长度进行了讨论,研究了激光器的最佳光纤长度。研究结果表明:腔镜反射率越小,阈值泵浦光功率和输出光功率越大。当激光器工作于最佳光纤长度时,输出光功率最大。

掺铒光纤放大器放大特性分析

介绍了掺铒光纤放大器(EDFA)的基本工作原理,建立了放大特性理论模型。并在不同条件下模拟仿真了其增益特性。揭示了EDFA的增益特性与泵浦光功率、掺铒光纤长度(EDF)的关系。

基于OptiSystem的掺铒光纤放大器增益特性研究

光放大器能直接放大光信号,通过补偿传输中功率的损耗而延长无电中继的传输距离,从而大大简化系统结构,降低系统成本。掺饵光纤放大器是应用最广泛的放大器之一。论文应用Opti System软件搭建了正向、反向,双向3种掺铒光纤放大器(EDFA)的基本结构,分析了饵光纤长度、泵浦光功率对EDFA增益特性的影响,得出仿真结论。

基于OPTISYSTEM的掺铒光纤放大器噪声特性仿真分析

EDFA本身产生噪声,使信噪比下降,造成传输距离的限制,故噪声特性是EDFA的一项重要指标。本文使用Opti System软件搭建了正向,反向,双向三种掺铒光纤放大器(EDFA)的基本结构,分析了泵浦光功率对EDFA噪声特性的影响,得出仿真结论。

1.55μm光纤技术在有线电视系统中的应用

众所周知,在光纤传输的三个窗口中,0.85μm窗口的损耗太大,在有线电视系统中不能使用;1.31μm窗口的损耗较低,色散最小,价格也较便宜,在光纤有线电视系统中用的最多;1.55μm窗口的损耗最小,但色散较大,前几年的价格较贵,技术也不太成熟,使它的应用受到限制。近年来,1.

Generating large steady-state optomechanical entanglement by the action of Casimir force

In this paper, we study an optomechanical device consisting of a Fabry-P6rot cavity with two dielectric nanospheres trapped near the cavity mirrors by an external driving laser. In the condition where the distances between the nanospheres and cavity mirrors are small enough, the Casimir force helps the optomechanical coupling to induce a steady-state optomechanical entanglement of the mechanical and optical modes in a certain regime of parameters. We investigate in detail the dependence of the steady- state optomechanical entanglement on external control parameters of the system, i.e., the effective detuning, the pump powers of the cavity, the cavity decay rate and the wavelength of the driving field. It is found that the large steady-state optomechanical entanglement, i.e. EN = 5.76, can be generated with experimentally feasible parameters, i.e. the pump power P = 18.2 μW, the cavity decay rate K = 0.5 MHz and the wavelength of the laser AL=1064 nm, which should be checked by optical measurement.

A dynamic optical arbitrary waveform generator based on cross phase modulation

In this paper, a dynamic optical arbitrary waveform generator(OAWG) based on cross phase modulation(XPM) is proposed. According to the characteristics of XPM, the nonlinear phase shift of signal can be changed along with the pump power. The amplitude of signal can be changed by controlling the phase shift at one arm of a Mach-Zehnder interferometer(MZI) using XPM effect between signal and pump. Therefore, the phase and amplitude of the optical frequency comb(OFC) can be controlled by two pump arrays. As a result, different kinds of waveforms can be synthesized. Due to the ultrafast response of XPM, the generated waveform could be dynamically updated with an ultrafast frequency. The waveform fidelity is affected by the updating frequency.

A flexible receiver with fiber optical parametric amplifier in OCDMA-FSO communication system

A new receiver is proposed, which uses the fiber optical parametric amplifier(FOPA) in optical code division multiple access(OCDMA) over free space optic(FSO) communication system. The noise tolerance as the performance index in this receiver is derived. The receiver can not only improve the noise tolerance but also change the pump data conveniently for adapting to the length variation of the coding sequence under a complex and fast-changing weather condition. The influence of different factors on the noise tolerance is analyzed, and a significant improvement of about 18.77 d B for the noise tolerance can be achieved when the pump power and the length of coding sequence are 5 W and 256, respectively.

The polarization-dependent supercontinuum generation in photonic crystal fibers with high birefringence and two-zero dispersion

A polarization-dependent supercontinuum spectrum source of light from the UV to infrared region has been generated in our photonic crystal fiber with birefringence B=2.23×10 3.By tuning the polarization direction of the input pulse,it is found that the width of the supercontinuum spectrum changes dramatically with the input polarization directions.At the same time,we qualitatively explain the blue-shift peak and the red-shift peak in the experimental spectrum using phase matching conditions on dispersive waves,stoke waves and the pump wave.In addition,we also found that supercontinuum spectrum generation,to some extent,is dependent on the pump wavelength and average power of the pump.The spectrum is broadened with the increase of average power,but unchanged after average power reaches a certain value;when the pump wavelength is located in the anomalous dispersion and further away from the zero-dispersion wavelength,the spectrum of the supercontinuum is wider.

Room-temperature light emission from an airbridge double-heterostructure microcavity of Er-doped Si photonic crystal

We experimentally demonstrate an efficient enhancement of luminescence from two-dimensional(2D) hexagonal photonic crystal(PC) airbridge double-heterostructure microcavity with Er-doped silicon(Si) as light emitters on siliconon-insulator(SOI) wafer at room temperature.A single sharp resonant peak at 1 529.6 nm dominates the photoluminescence(PL) spectrum with the pumping power of 12.5 m W.The obvious red shift and the degraded quality factor(Q-factor) of resonant peak appear with the pumping power increasing,and the maximum measured Q-factor of 4 905 is achieved at the pumping power of 1.5 m W.The resonant peak is observed to shift depending on the structural parameters of PC,which indicates a possible method to control the wavelength of enhanced luminescence for Si-based light emitters based on PC microcavity.

Experimental investigation of the influence of laser intensity on the quality of Einstein-Podolsky-Rosen entangled photons

Using spontaneous parametric down conversion,polarization post selection and coincidence counting technique,the polarization Einstein-Podolsky-Rosen(EPR) entangled states are prepared.Experimental studies on the efficiency,contrast and fidelity with different pump laser intensities are performed systematically.The results show that the pump laser intensity distinctly influences the quality of entangled photons,especially the contrast and the fidelity.On the other hand,the pump efficiency of entangled photons is almost invariable,namely the entangled source brightness increases linearly with the increase of pump laser power.