Preparation and Detection of Extended DNA Fibers of Chinese Cabbage

Abstract [Objective] The paper was to prepare and detect the extended DNA fibers of Chinese cabbage. [Method] Chinese cabbage nuclei was first successfully isolated by chopping young leaves with a blade, then nuclei were lysed by SDS to release DNA, and DNA fibers were dragged and extended with a coverslip. [Result] The results of Fiber-FISH with genomic DNA and 25S rDNA as probes showed that DNA fiber size as long as about 1.93 Mb could be measured and the number of 25S rDNA copies region were estimated to be 258 and 687 in Chinese cabbage genome. DNA fibers prepared by this method showed equally spread parallel thread with clear background, and were suitable for FISH analysis. [Conclusion] The study would accelerate Chinese cabbage genome mapping and organization analysis.

A Temperature-Insensitive Amplified Spontaneous Emission Broadband Source Based on Er-Doped Fiber

To obtain a stable amplified spontaneous emission（ASE） source for complex environment applications, we design an ASE source and study the output power and spectral characteristics under different ambient temperatures.We optimize the structure of the ASE source to flatten the ASE spectrum, and study the output characteristics in terms of output power and optical spectrum under different pump powers. Then the performance of the ASE source is investigated in the temperature range from-18.9°C to 50°C. A stable-power and flat-spectrum ASE source can be obtained by structural optimization and pump control.

Mode-Locked Erbium-Doped Fiber Laser Using Vanadium Oxide as Saturable Absorber

A mode-locked erbium doped fiber laser（EDFL） is demonstrated using the vanadium oxide（V2O5） material as a saturable absorber（SA）. The V2O5 based SA is hosted into poly ethylene oxide film and attached on fiber ferule in the laser cavity. It shows 7% modulation depth with 71 MW/cm2 saturation intensity. By incorporating the SA inside the EDFL cavity with managed intra-cavity dispersion, ultrashort soliton pulses are successfully generated with a full width at half maximum of 3.14 ps. The laser operated at central wavelength of 1559.25 nm and repetition frequency of 1 MHz.

Erbium-Doped Zirconia-Alumina Silica Glass-Based Fiber as a Saturable Absorber for High Repetition Rate Q-Switched All-Fiber Laser Generation

We propose and demonstrate a Q-switched erbium-doped fiber laser （EDFL） using an erbium-doped zirconia-alumina silica glass-based fiber （Zr-EDF） as a saturable absorber. As a 16-cm-long Zr-EDF is incorporated into a ring EDFL cavity, a stable Q-switching pulse train operating at 1565？nm wavelength is successfully obtained. The repetition rate is tunable from 33.97？kHz to 71.23？kHz by increasing the pump power from the threshold of 26？mW to the maximum of 74？mW. The highest pulse energy of 26.67？nJ is obtained at the maximum pump power.

Harmonic Dark Pulse Emission in Erbium-Doped Fiber Laser

A harmonic dark pulse generation in an erbium-doped fiber laser is demonstrated based on a figure-of-eight configuration. It is found that the harmonic dark pulse can be shifted from the fundamental to the 5th order harmonic by increasing the pump power with an appropriate polarization controller orientation. The fundamental repetition rate of 2O kHz is obtained at the pump power of 29 m W. The highest pulse energy of 42.6 n3 is obtained at the fundamental repetition rate. The operating frequency of the dark pulse trains shifts to 2nd, 3rd, 4th and 5th harmonic as the pump powers are increased to 34mW, 50mW, 59mW and 137mW, respectively.

Using Reduced Graphene Oxide to Generate Q-Switched Pulses in Er-Doped Fiber Laser

Using the reduced graphene oxide（rGO） as a saturable absorber（SA） in an Er-doped fiber（EDF） laser cavity,we obtain the Q-switching operation. The rGO SA is prepared by depositing the GO on fluorine mica（FM） using the thermal reduction method. The modulation depth of rGO/FM is measured to be 3.2%. By incorporating the rGO/FM film into the EDF laser cavity, we obtain stable Q-switched pulses. The shortest pulse duration is3.53 μs, and the maximum single pulse energy is 48.19 nJ. The long-term stability of working is well exhibited.The experimental results show that the rGO possesses potential photonics applications.

Experimental Observation of Bright and Dark Solitons Mode-Locked with Zirconia-Based Erbium-Doped Fiber Laser

We demonstrate the generation of dark and bright solitons with our homemade zirconia-based erbium-doped fiber and graphene oxide（GO） saturable absorber in anomalous dispersion region.The GO is fabricated using an abridged Hummer＇s method,which is combined with polyethylene oxide to produce a composite film.The film is sandwiched between two optical ferrules and embedded in the laser cavity to enhance its birefringence and nonlinearity.The self-starting bright soliton is easily generated at pump power of 78 mW with the whole length cavity of 14.7 m.The laser produces the bright pulse train with repetition rate,pulse width,pulse energy and central wavelength being 13.9 MHz,0.6 ps,2.74 p J and 1577.46 nm,respectively.Then,by adding the 10 m of single mode fiber into the laser cavity,dark soliton pulse is produced.For the formation of dark pulse train,the measured repetition rate,pulse width,pulse energy and central wavelength are 8.3 MHz,20 ns and 4.98 p J and1596.82 nm,respectively.Both pulses operate in the anomalous region.

Passively Q-Switched Erbium-Doped Fiber Laser with TiSe₂as Saturable Absorber

The TiSe2 nanosheets were prepared by means of ultrasound-assisted liquid phase exfoliation (LPE) and the nonlinear saturable absorption properties were experimentally investigated. The modulation depth, saturation intensity and nonsaturable absorbance of the prepared 1T-TiSe2 SA were 15.7%, 1.28 MW/cm2 and 8.2%, respectively. Taking advantage of the saturable absorption properties of TiSe2-based SA, a passively Q-switched erbium-doped fiber (EDF) laser was systematically demonstrated. The pulse repetition rates varied from 24.50 kHz up to 73.79 kHz with the increasing pump power. The obtained shortest pulse width was 1.31 μs with pulse energy of 79.28 nJ. The system presented merits of low-cost SA preparation, system compactness, superb stability and high competition.

大功率高效率掺铒超荧光光纤光源及其应用

采用光纤反射环镜和双程后向结构 ,得到了最大输出功率 30 .6mW、光光转换效率 4 2 .0 %的大功率、高效率全光纤掺铒超荧光光源 (SFS) 利用串接光纤光栅 (FBG)和光纤型F P腔 ,对其进行光谱分割 ,得到了稳定的多波长输出

慢光产生的新机理及其应用

通过对比和研究电磁感应透明、相干布居振荡、受激布里渊散射和光子晶体波导等几种使光速变慢的主要技术,论述了近10年中的慢光技术重要理论和技术上的发展以及这些发展对慢光性能的改善及存在的问题与不足,重点介绍了近几年慢光产生的一些新技术及初步应用,并预测了慢光技术今后的发展趋势及潜在应用。本文的研究表明,慢光在光纤传感以及其它领域中将会有越来越重要的应用价值。

一种高功率掺铒光纤超荧光光源

通过优化掺铒光纤各种参量,用一个980nm激光二极管作抽运源,采用单程结构,在一根光纤后向获得功率高达31.74mW(15.02dBm)的C波段ASE输出的同时,其前向得到了功率为10.14mW(10.06dBm)的L波段ASE输出.通过简单连接组合可得到输出覆盖C+L波段(1525～1620nm)功率>36mW的掺铒光纤宽带光源.

新型三段高性能的长波段掺铒光纤超荧光光源的研究(英文)

提出了一种第一段无泵浦、第二段前向泵浦和第三段后向泵浦的三段级联掺铒光纤超荧光光纤光源的新结构.数值分析了泵浦光波长、铒光纤长度以及泵浦比例对新结构性能的影响.结果表明可以找到一组适合制作成本低廉、输出功率高、谱平坦的长波段掺铒光纤超荧光光源.

任意波形脉冲泵浦下掺铒光纤的自发辐射

为了突破以往研究的波形局限,探究任意波形脉冲泵浦下掺铒光纤的自发辐射特性,从速率方程组出发,采用分时段计算的方法得到各能级粒子数及自发辐射平均功率的表达式.仿真和实验表明,泵浦光毛刺对自发辐射光的影响较小,具有类似"高频滤波"的特性;泵浦功率较大时自发辐射光的波形与泵浦波形接近,该研究结果可以用于光纤激光器的全光调制.理论分析与实验结果相符合,证明了理论的可靠性.

双程后向结构掺铒光纤超荧光光源研究

通过编制 1套图形界面的模拟分析软件 ,对双程后向结构掺铒光纤超荧光光源有关输出功率、带宽和平均波长特性进行了理论模拟。结果表明 ,通过选取适当的掺铒光纤长度 ,总能实现光源的平均波长不依赖于泵浦功率的高稳定性。

光纤光栅传感器用的高功率宽带光源

运用单程后向结构,通过优化掺Er光纤结构,从实验上实现了一种功率达29.4mW,平均波长为1544.336nm的高功率宽带掺Er超荧光光源,3dB带宽为31.2nm,在C波段1525～1565nm之间可实现功率高于27.8mW,在1532.1～1560.6nm之间的平坦度可达±0.5dB(不加任何滤波器的条件下),可以较好地满足光纤Bragg光栅在传感领域的研究和实用化的应用要求,作为单独的光源也适用于光纤陀螺等场合。

我国掺稀土光纤的现状分析

掺稀土光纤作为激光增益介质在光纤通信、光纤激光器和传感器等领域有着广泛的应用,国内掺铒光纤、掺镱光纤的市场曾长期被Corn ing、Lucent等国外光纤制造厂商所垄断,近年来我国掺铒光纤、掺镱光纤的研究取得了很大进展,已部分替代国外进口。文章主要介绍国内掺铒光纤、掺镱光纤的研究现状和发展趋势。

双级双抽运结构掺铒光纤光源的分析研究

为了研究双级双抽运结构C＋L波段放大自发辐射宽带光源的两级光纤长短搭配不同对输出光谱特性的影响，采用软件模拟仿真和实验验证相结合的方法，进行了理论分析和实验对比。结果表明，当第1级光纤较短、第2级光纤较长时，可实现功率为18．04,W（12．56dBm）、抽运光利用效率为13．9％、平坦度小于±3．97dB（1525nm～1600nm）的C＋L波段放大自发辐射输出；当第1级光纤较长、第2级光纤较短时，可实现功率为20．07mW（13．02dBm）、抽运光利用效率为16．7％、平坦度小于±1．89dB（1525nm～1600nm）的C＋L波段放大自发辐射输出。采用第1级光纤较长、第2级光纤较短的双级双抽运是一种更为理想的C＋L波段放大自发辐射光源结构。

新颖的高功率L-波段掺铒光纤超荧光光源

研究了L-波段超荧光在光纤中的产生机理,设计了一种带光纤圈反射器的双级双程前向输出L-波段光源结构,通过对两级采用掺铒浓度不同的光纤并优化其长度及两级泵浦光功率,实验中获得了功率高达19.86mW(12.98dBm)、中心波长为1577.421nm的L-波段(1555-1620nm)超荧光光源。实现了低浓度掺铒光纤起诱导光及改善光谱的作用,高浓度光纤为主要发光源,采用光纤圈反射器提高了泵浦光的利用效率、光源的平坦度及稳定性。同时分析了结构中各个参量对光源各方面性能的影响,对光源的设计具有指导意义。

一种高效率的L波段掺铒光纤ASE宽带光源

利用双程双向泵浦单级掺铒光纤的结构实现高效率的L波段掺铒光纤放大自发辐射输出，同时选择1480nm半导体激光器作为泵浦源，高掺杂铒光纤为增益介质，通过优化铒光纤长度，获得了在1566～1604nm（38nm），自发辐射谱功率高于-16dBm，总输出功率13．7dBm的L波段掺铒光纤放大自发辐射光源。该光源结构相比于双程前向泵浦结构的L波段掺铒光纤放大自发辐射光源，其泵浦效率从11．8％提高到23．4％。

脉冲泵浦掺铒光纤增益调制特性的研究

本文研究了预激光调Ｑ选模ＹＡＧ倍频激光脉冲泵浦掺铒光纤（ＥＤＦ）的荧光特性。由于存在信号光诱导的共振受激辐射，反转粒子数迅速地回复到基态，受激辐射寿命比亚稳态寿命低四个量级。基于这一效应，本文研究了调制的１．４６μｍ半导体激光器泵浦ＥＤＦ，观察到１０ｋＨｚ以上增益调制，可用以设计快速响应的有源光纤开关器件。