An Integratable Distributed Bragg Reflector Laser by Low-Energy Ion Implantation Induced Quantum Well Intermixing

An integratable distributed Bragg reflector laser is fabricated by low energy ion implantation induced quantum well intermixing.A 4 6nm quasi continuous wavelength tuning range is achieved by controlling phase current and grating current simultaneously,and side mode suppression ratio maintains over 30dB throughout the tuning range except a few mode jump points.

Spectral Beam Combining of Fiber Lasers by Using Reflecting Volume Bragg Gratings

By employing three reflecting volume Bragg gratings, a near-infrared 4-channel spectral-beam-combining system is demonstrated to present 720 W combined power with a combining efficiency of 94.7%. The combined laser beam is near-diffraction-limited with a beam factor M^2-1.54. During this 4-channel beam-combining process, no special active cooling measures are used to evaluate the volume Bragg gratings as combining elements are under the higher power laser operation. Thermal expansion and period distortion are verified in a 2 k W 2-channel beam-combining process, and the heat issue in the transmission case is found to be more remarkable than that in the diffraction e-se. Transmitted and diffracted beams experience wave-front aberrations with different degrees, thus leading to distinct beam deterioration.

Implementation of Phase Generated Carrier Technique for FBG Laser Sensor Multiplexed System Based on Compact RIO

This paper presents the fundamental technique of phase generated carrier （PGC） and its realization on compact reconfigurable input and output （RIO） which adopts real-time and field programmable grate array （FPGA） techniques. Improvement of the PGC technique is also introduced by using peak-to-peak value detection method to reduce the influence of variation of the light intensity. A four-element fibre Bragg gratings （FBG） laser sensor system is conducted in the experiment and the demodulated results demonstrate correlation coefficient as high as 0.995 with the reference signal and the dynamic range to be 120dB@63Hz.

Widely Tunable Sampled-Grating DBR Laser

The 3-section SG-DBR tunable laser is fabricate d using an ion implantation quantum-well intermixing process.The over 30nm discontinuous tuning range is achieved with the SMRS greater than 30dB.

A Wavelength Tunable DBR Laser Integrated with an Electro-Absorption Modulator by a Combined Method of SAG and QWI

We report a wavelength tunable electro-absorption modulated DBR laser based on a combined method of SAG and QWI. The threshold current is 37mA and the output power at 100mA gain current is 3.5mW. When coupled to a single-mode fiber with a coupling efficiency of 15% ,more than a 20dB extinction ratio is observed over the change of EAM bias from 0 to -2V. The 4.4nm continuous wavelength tuning range covers 6 channels on a 100GHz grid for WDM telecommunications.

Bragg激光系统之间信号的同步传输

研究了具有相互耦合的三台Bragg激光系统之间信号的同步传输。在这种同步机理中,前一级激光系统的输出信号被提取一部分线性耦合到下一级激光系统中,逐级驱动多级激光系统达到信号的同步传输。基于稳定性定理,通过计算每个激光系统的Lyapunov指数,确定了实现多级激光器完全同步的条件。

2-μm mode-locked nanosecond fiber laser based on MoS_2 saturable absorber

We demonstrated a 2-μm passively mode-locked nanosecond fiber laser based on a MoS2 saturable absorber（SA）.Owing to the effect of nonlinear absorption in the MoS2 SA, the pulse width decreased from 64.7 to 13.8 ns with increasing pump power from 1.10 to 1.45 W. The use of a narrow-bandwidth fiber Bragg grating resulted in a central wavelength and 3-dB spectral bandwidth of 2010.16 and 0.15 nm, respectively. Experimental results show that MoS2 is a promising material for a 2-μm mode-locked fiber laser.

基于可调谐半导体激光器的高分辨率多路复用光纤光栅波长解调系统

构建了一套高分辨率的可复用光纤光栅波长解调系统.采用波长调谐范围为1 546nm至1 558nm的紧凑型可调谐半导体激光器作为光源,来提高系统的紧凑性、波长分辨率以及响应速度,加入标准气室作为波长基准以提高系统的长期稳定性.使用多个电极电流共同调谐的办法,实现了在12nm范围内半导体激光器波长分辨率高达1pm的准连续波长扫描.利用重心算法提高光纤光栅中心波长的解调精确度和稳定性,并对解调过程进行模拟.解调系统的波长分辨率优于1pm,精确度接近2pm.整个光纤布拉格光栅温度传感系统在1 550nm附近实现了0.1℃的温度分辨率.

自激发多波长可开关掺铒光纤激光器

波长可开关光纤激光器可以选择多波长光纤激光器中的一个或多个波长输出,支持光网络中多个波长的动态分配,适应现代光纤通信系统信道数越来越多的波分复用和密集波分复用的发展方向.本文提出并实现了一种自激发多波长可开关掺铒光纤激光器.该激光器通过一个980nm泵浦进行抽运,使用掺铒光纤作为增益介质,产生1 550nm光谱,并通过一个环形结构返回,从而实现自激发的过程,降低了实验成本.实验使用一个含有两段保偏光纤的Sagnac环作为滤波器.通过调整Sagnac环形滤波器内偏振控制器的角度,改变Sagnac环形滤波器的腔内增益,可以让光纤光栅反射出来的波长选择性通过,从而实现波长的开关功能.实验证明,通过调整Sagnac滤波器的腔内增益而让多波长选择性通过,是一种有效的实现波长可开关功能的方法.

基于MG-Y型可调谐半导体光源的光纤光栅解调系统研究

介绍了一种基于调制光栅Y分支(MG-Y)可调谐光源的光纤光栅解调系统。该系统由可调谐光源控制系统和光电探测电路组成。光源系统由ARM处理器对单片集成恒流源芯片和高精度温度控制芯片控制;光电探测电路是由光电二极管和高动态范围的对数放大电路组成,用于接收光纤光栅反射信号。针对基于可调谐扫描光源的硬件系统研究,提出采用波长计实现查找表的方法,构建了"波长-电流"精确转换模型,实现了光纤光栅解调仪的装配与调试。实验对可调谐光源进行测试,该光源在1527~1567 nm光谱范围能够按照20 pm间隔依次输出2001个激光,扫描波长间隔偏差最大为8 pm,功率波动小于4.5 dBm;在F-P标准具验证实验中,解调仪能够对40 nm范围内的52个反射峰实现分辨。

Q-switched pulse generation from an all-f iber distributed Bragg reflector laser using graphene as saturable absorber

A Q-switched distributed Bragg reflector fiber laser using a graphene passive saturable absorber is proposed in a cavity consisting of a fiber Bragg grating and Faraday rotator mirror as end mirrors, together with a highly doped erbium-doped fiber as a gain source. The laser has a Q-switched threshold of about 28 mW and a tunable repetition rate of 10.4-18.0 kHz with varying pump power. The shortest pulse width obtained from the system is 3.7 its, with a maximum pulse energy and peak power of 22.2 nJ and 3.4 mW, respectively.

A self-seeded fiber laser incorporated with a fiber Bragg grating external cavity semiconductor laser

A self-seeded fiber laser incorporated with a fiber Bragg grating external cavity semiconductor laser (FBG-ECL) and a Mach-Zehnder interferometer (MZI) were reported in this paper. The MZI provided a Q-switching with response time in the order of micro-seconds. The FBG-ECL provided narrow pulses as seeds to shorten the Q-switched pulses. Experimentally, pulse width of 0.8 μs was measured, which was one fifth of the pulse width without self-seeding.

Frequency and wavelength tunable optical microwave source based on a distributed Bragg reflector self-pulsation laser

A frequency and wavelength tunable self-pulsation laser based on DBR laser devices is reported for the first time.This laser generates continuous tunable optical microwave in the range of 1.87-21.81 GHz with 3-dB linewidth about 10 MHz by tuning the injection currents on the front and back gain sections,and exhibits wavelength tuning range from 1536.28 to 1538.73 nm by tuning the injection currents on the grating section.

Effects of the Facet Reflectivity of a Laser Diode on Fiber Bragg Grating Semiconductor Lasers

Effects of facet reflectivity of a laser diode on the performance of fiber Bragg grating semiconductor lasers are studied experimentally. Facet reflectivity of less than 10-4 is necessary to obtain stable oscillation wavelength.

基于扫描激光器的边孔光纤光栅温度压力传感系统

研究了一种基于波长扫描激光器的光纤温度压力测量系统.光纤传感头为边孔光纤光栅,利用其特有的双折射特性产生双反射峰,以实现对温度和压力的同时测量.系统采用嵌入式开发技术,将激光波长扫描、光谱数据采集和以牛顿最小二乘法为核心的光栅解调算法高度整合于一体,极大降低了光纤传感系统的体积与成本.实验结果表明,在温度10～50℃、压力0～1.2 MPa时,双反射峰对应温度与压力的变化均呈现良好的线性响应特性;系统的波长解调准确度可达1pm,温度及压力的分辨率分别达到0.1℃和0.1 MPa.该系统可为温度、压力的参量测量提供低成本、小型化、性能可靠的解决方案.

Temperature-controlled mode selection of Er-doped random fiber laser with disordered Bragg gratings

In this paper, we proposed a way to realize an Er-doped random fiber laser(RFL) with a disordered fiber Bragg grating(FBG) array, as well as to control the lasing mode of the RFL by heating specific locations of the disordered FBG array. The disordered FBG array performs as both the gain medium and random distributed reflectors, which together with a tunable point reflector form the RFL. Coherent multi-mode random lasing is obtained with a threshold of between 7.5 and 10 mW and a power efficiency between 23% and 27% when the reflectivity of the point reflector changes from 4% to 50%. To control the lasing mode of random emission, a specific point of the disordered FBG array is heated so as to shift the wavelength of the FBG(s) at this point away from the other FBGs.Thus, different resonance cavities are formed, and the lasing mode can be controlled by changing the location of the heating point.

Wavelength Tuning in the Two-Section Distributed Bragg Reflector Laser Fabricatedby Quantum-Well Intermixing

The two-section tunable ridge waveguide distributed Bragg reflector (DBR) lasers fabricated by strained In xGa1-xAsyP1-y The threshold current of the laser is 51mA. The tunable range of the laser is 3.2nm and the side mode suppression ratio (SMSR) is more than 38dB.

基于光纤光栅温度传感器的BP-PID选择性激光烧结温度控制系统

为消除选择性激光烧结系统中温度调控纯滞后系统的超调,提高温度控制的灵活性与准确性,文中设计了一种基于光纤光栅温度传感器的BP-PID的选择性激光烧结温度控制系统。在硬件上使用光纤对温度变化进行精密测量,利用BP神经网络改进PID算法,提高控制系统的稳定性。给出基于光纤光栅阵列的温度监控系统模型,通过BP-PID算法迅速整定最优参数。结果表明基于该方法的超调量较小,达到稳态所用的时间更短。在设定预热温度为200℃时,采用BP-PID算法控制系统稳态误差在±3℃之内,超调量小于3%。

Regenerated fiber Bragg grating for fiber laser sensing at high temperatures

Thermally regenerated low-reflectivity fiber Bragg gratings（RFBGs）, as one mirror of a resonant cavity, have been introduced as linear-cavity fiber lasers combining with fiber saturable absorbers. The output of lasing presents an optical signal-to-noise ratio of 50 dB and temperature sensitivity coefficient of 15.36 pm∕℃ for the heating process and 15.46 pm∕℃ for the cooling process. The lasing wavelength variation and power fluctuation at 700℃ are less than 0.02 nm and 0.21 dB, respectively. The RFBG-based fiber laser sensing has displayed good linearity for both the temperature rising and cooling processes, and favorable stability at high temperatures.

高效声光调制器研究

本文根据声光互作用的基本理论以及结合Bragg方法 ,提出了一种线性调制器的设计方法。该设计方法比以往传统设计方法的主要优点是提高了衍射效率。论文还叙述了利用该设计方法制作声光器件的过程 ,制作了以Ge为声光介质、中心频率为 80MHz、带宽为 10MHz的可见光声光调制器。最后给出了设计方法的实验数据 ,充分证明这种设计方法的可行性。