宽调谐范围垂直腔面发射激光器特性分析及设计

运用光学传输矩阵和有限元方法对波长可调谐垂直腔面发射激光器(VCSELs)的波长调谐范围进行了研究.对中心波长为980nm的可调谐VCSELs的波长调谐特性和微电子机械系统(MEMS)悬臂梁结构进行了设计，并进行了实验研究.结果表明，MEMS可调谐VCSELs调谐特性同时受到光波谐振腔结构和悬臂梁最大位移的共同影响.在悬臂梁几何尺寸和激光器有源区结构一定的条件下，通过优化可调谐VCSELs的牺牲层厚度可实现大范围波长调谐.同时，对可调谐VCSELs整体结构进行了设计，计算结果显示波长调谐范围达到30nm以 关键词： 悬臂梁 可调谐垂直腔面发射激光器     

外腔半导体激光器激光波长连续可调范围的研究

在此研究了利特曼结构和利特罗结构的外腔半导体激光器激光波长连续可调范围和反射镜转轴等关键几何位置与结构的机械加工或制作误差的关系，详细分析了由于制作工艺、技术精度等因素所造成的各种误差对激光器连续可调谐范围的影响。     

Single resonant and widely tunable ultrathin cladding long-period fiber grating filters

A spectrally single resonant and widely tunable, ultrathin cladding long-period fiber grating (UCLPG) is demonstrated in the present paper. Both experimental and theoretical analyses of the characteristics for the proposed device are accomplished. Since the single resonant and widely tunable characteristics of the proposed UCLPG are strongly influenced by the waveguide structure and surrounding material, both material dispersion and waveguide dispersion were included in the calculation for determining the wideband tuning range and resonant spectra of the UCLPG. The tuning range covered wavelength from 1.41 to 1.56 μm for the variation of refractive index of 1–1.445 (optical liquid n _D 1:456 for λ 1:5 mm) is achieved in the study.     

新型结构可调谐全光波长转换器的理论与实验研究

可调谐波长转换器是智能化光网络中的关键光电子器件. 提出了一种基于半导体光放大器的环形激光器实现连续可调全光波长转换的方案，建立了该方案的理论模型. 理论计算和实际测定了不同条件下波长转换的输出特性，实验结果与理论计算基本符合. 实验中实现了40nm范围内连续可调、转换速率为2.5Gb/s的交叉增益调制型波长转换. 关键词： 可调谐波长转换 半导体光放大器 环形腔     

C-band continuously tunable lasers using tunable fiber Bragg gratings

We report the development of a ring tunable fiber laser based on tunable fiber Bragg gratings (TFBG) integrated with an optical circulator. The TFBG is embedded inside a 3-piont bending device for wavelength tuning. The tunable laser operating in the C-band has power variation, tuning resolution, tuning range and laser line width of ±0.5 dB, 0.5 nm, 25.0 nm and less than 0.05 nm, respectively. As 40 mW of pump power is used, the ring tunable laser has a side mode suppression ratio of 60 dB and a power conversion efficiency of 25%. These specifications ensure the high-quality operation of a tunable laser.     

互注入锁定产生双波长可调谐光脉冲的实验研究

报道了两个增益开关调制的法布里-珀罗半导体激光器互注入锁定实验方案,可产生双波长可调谐光脉冲。该装置对两个结构基本相同的法布里珀罗半导体激光器做增益开关调制,产生多模光脉冲输出;然后利用两个光纤光栅作为滤波元件,通过调节可调谐光延迟线(VODL2),可使得双波长光脉冲在两个法布里-珀罗激光器之间相互注入锁定．从而在输出端得到高边模抑制比的双波长光脉冲输出。然后再通过应力作用在两个光纤光栅上以改变它们的反射波长和适当调整另一个可调谐光延迟线(VODLI)长度．可得到不同的双波长的光脉冲输出,而重复频率保持524．6MHz不变。在13．2nm调谐范围内边模抑制比高于25dB．系统稳定且波长调节方便。     

Cost-effective tunable fiber laser based on self-seeded Fabry-Perot laser diode using a Sagnac loop reflector

We propose and demonstrate a simple configuration of wavelength-tunable fiber laser made up of a tunable band-pass filter, a Sagnac loop refiector, and a Fabry-Perot laser diode. Based on the self-seeded operation, the proposed fiber laser can obtain a single-longitudinal-mode output in the wavelength tuning range of 1544.69–1563.39 nm with tuning step of 1.34 nm. The performances of output power （-9 dBm）, optical side-mode suppression ratio （ 65.5 dB）, and power and wavelength stabilities are well exhibited.     

Tunable fiber Bragg gratings for application in tunable fiber lasers

The resonance wavelength of the fiber Bragg gratings (FBGs) is tuned using two methods. Tunable FBGs are used as the selecting elements in the cavities of tunable lasers. An ytterbium-doped fiber laser with a wavelength tuning range of 1063–1108 nm and an output power of 6 W, a Raman fiber laser with a wavelength tuning range of 1252–1303 nm and an output power of 3 W, and an erbium-doped fiber laser with a wavelength tuning range of 1530–1580 nm are realized, and their characteristics are studied.     

宽范围可调谐内腔液晶垂直腔面发射激光器设计与研究

为增加可调谐激光器的波长调谐范围,提高系统的可靠性和稳定性,基于液晶的电控双折射特性,设计了一种中心波长为852 nm的内腔液晶可调谐垂直腔面发射激光器结构。分析了该结构获得宽范围波长调谐和单偏振稳定输出的物理原理,利用传输矩阵法进一步计算整个器件下不同液晶层厚度所对应的反射谱,得出不同液晶厚度和折射率下激光器的激射波长。结果表明,液晶可调谐激光器单偏振波长调谐范围达到31 nm,调谐效率大于10 nm/V。     

Widely ultra-narrow linewidth 104 nm tunable all-fiber compact erbium-doped ring laser

A widely tunable narrow linewidth compact erbium-doped all-fiber ring laser with 104 nm tuning range was reported. An all-fiber Fabry-Perot filter (FFP-TF) was used to realize the laser tuning output, and the wavelength at constant voltage had high time stability. With the 8 m length erbium-doped fiber as gain medium, we realized widely tunable laser from 1513 to 1617 nm with the linewidth less than 40 pm at any wavelength. Pumped by the 976 nm laser diode, the fiber laser worked with slope efficiency of above 10% and threshold of less than 21 mW.     

级联光栅结合Sagnac环的可调谐光纤激光器

提出并验证了一种单-双波长可调谐掺铒光纤激光器。利用级联光纤布拉格光栅(Cascaded Fiber Bragg gratings,Cascaded FBGs)结合Sagnac环结构所产生的复合滤波效应,实现较高精细度滤波,并通过调节环内偏振控制器(Polarization Controller,PC),引入双折射效应,得到波长可调谐的光纤激光器。基于耦合模理论并使用传输矩阵法对该结构的传输特性进行了分析,在此基础上搭建实验系统,验证了理论分析的正确性。实验结果表明:通过调节PC,激光器输出激光的波长范围约为1 555.644～1 556.112 nm,双波长间隔的可调范围约为0.108～0.452 nm,单-双波长的边模抑制比(SMSR)均高于40 dB;在稳定性测试中,输出单-双波长激光的波长最大漂移量小于0.008 nm。该方法具有结构简单、调谐方便、易于实现且精细度较高的优点,可应用于密集波分复用及全光通信系统等领域。     

单片集成微环反射器可调谐半导体环形激光器理论和数值模型(英)

设计了一种新颖的快速可调谐激光器。这种激光器在恒定电流泵浦的有源微环组成的半导体环形激光器腔外部集成一个可调谐的无源微环反射器,其结构将决定激光器激射腔模的有源腔和无源可调谐部分分离,有助于提高调谐速度。与光栅结构的激光器相比,该激光器结构简单,具有强烈的选模功能,不需要相位匹配部分,输出波长不受调谐部分热效应的影响。基于多模速率方程建立了激光器的理论和数值模型,数值仿真结果表明该激光器能在选取的15个腔模范围内完成数字调谐,且具有40 mA的较低阈值电流和适中的边模抑制比。     

稳定可调谐的单纵模多环形腔掺铒光纤激光器

提出了一种多环形腔(MRC)结构的稳定可调的单纵模(SLM)掺铒光纤激光器,多环形腔结构由双环形有源腔和两个次级无源腔组成.这种激光器是利用光纤法布里珀罗可调滤波器(FFP-TF)以及光学光栅滤波器(OGF)两种滤波器和多环形腔结构相结合来共同选模.可实现波长调节范围为1528～1565 nm,在整个波长调节范围内边模抑制比大于44.53 dB,在1554 nm附近边模抑制比可以达到最大值51.18 dB, 输出功率为-8.84 dBm,通过应用多环型腔结构,激光器的输出很稳定,在18 min的观察时间内,中心波长的变化小于0.02 nm,输出功率的变化小于0.04 dBm,实现了稳定且可调谐的单纵模输出.     

Linewidth of SG-DBR laser and its effect on DPSK transmission

In this paper the linewidth of widely tunable SG-DBR lasers has been investigated theoretically and experimentally. We demonstrate experimentally the importance of obtaining low linewidth operation for the application of SG-DBR laser with advanced modulation format transmission. This is achieved by choosing two sets of tuning currents for an SG-DBR laser that give the same wavelength channel and good SMSR, but different linewidths. When the laser is employed in a DPSK system only the operating point (the set of drive currents used to obtain specific output characteristics) that portrays low linewidth achieves error free transmission. This work shows that although calibration of tunable lasers is normally based on achieving sufficient SMSR and output power, it will be important to consider the linewidth parameter as these lasers begin to be used in more spectrally efficient WDM systems employing advanced modulation formats. The simulation results illustrate that the operating points which achieve narrow linewidth are correlated with those that exhibit low threshold current. This finding may be used for calibration of SG-DBR lasers to achieve minimum linewidth at each operating wavelength.     

TDLAS氧气测量系统中激光器调谐性能测试与优化

TDLAS(可调谐半导体激光吸收光谱)技术以其分子光谱高选择性、速度快、灵敏度高、非接触测量等难以取代的优势,成为燃烧过程诊断等应用的首选,可以有效用于氧气测量。DFB(分布反馈)半导体激光器以其体积小、功耗低、寿命长、线宽窄、波长可调谐等优点成为TDLAS系统的主要选择,而其调谐特性是制约系统测量性能的关键因素。根据TDLAS氧气测量系统工作要求,采用一种简单易行的实验方法对系统中用到的764 nm DFB激光器的电流波长、温度波长和电流功率等重要调谐特性进行了测试和分析,发现出射光谱窄线宽、高边模抑制比和宽波长可调谐范围等特点明显,电流波长调谐曲线近似但并非严格线性、调谐速率约0.023 nm·mA-1,温度越高阈值电流越大、PI曲线也并非严格线性,温度调谐特性曲线线性较好、波长温度调谐速率基本保持恒定约为0.056 nm·℃-1。可见各种调谐曲线的非线性失真比较明显,影响氧气测量精度。温度调谐非线性可以通过温控精度的提高来消除,电流功率调谐非线性可以通过设置参考光强来消除。为了进一步解决电流波长调谐非线性问题,根据DFB半导体激光器的调谐机理和电流波长测试结果的多项式拟合,考虑通过DA控制注入电流的方式对电流波长调谐非线性进行补偿。这种方法针对不同激光器只需在系统初次工作之前进行一次多项式拟合,方案合理、实现简单且不影响测量过程。实验证明,补偿之后的λI曲线线性拟合残差小于1 pm,远小于补偿前的22 pm,效果明显,为氧气各种参数TDLAS精确测量和反演提供了依据。     

100nm宽光谱可调谐掺饵光纤激光器

采用1480 nm大功率激光二极管双向抽运,新型铋基掺饵光纤做增益介质,基于旋转法布里-珀罗腔的可调谐滤波器和带通滤波器做选频装置的宽光谱环形腔可调谐光纤激光器,可实现100 nm（1523~1623 nm）激光波长程控连续可调谐输出,激光输出功率大于1.58 mW,3 dB带宽小于0.1 nm,波长重复性准确度小于0.01 nm.     

785nm便携式光栅外腔可调谐半导体激光器的研制和输出特性

针对移频激发拉曼光谱测试系统的小型化需求,在Littrow结构中,采用商用的785nm大功率激光二极管作为增益器件,构建了一款便携式光栅外腔可调谐半导体激光器。该激光器通过采用一种新型的波长调谐方法,即以改变半导体增益器件相对于准直透镜的水平位置来实现波长的连续调谐,实现了尺寸为140mm×65mm×50mm的小型化结构设计。相比于传统的旋转衍射光栅改变光线在光栅上的入射角来实现波长调谐的方式,该方法有效地缩减了增益器件的平移距离,从而有利于便携式外腔激光器波长的快速宽带调谐。实验结果表明,该激光器具有较宽的波长调谐范围,在340~900mA注入电流下均可实现10nm以上的波长调谐,尤其在900mA大注入电流下,其波长调谐覆盖779.40~791.07nm,调谐范围可达11.67nm,且激射线宽小于0.2nm,单波长输出功率最高可达280mW,放大的自发辐射抑制比大于25dB,呈现出较优异的输出性能,满足移频激发拉曼光谱检测系统对光源的基本要求。此外,该激光器可采用一微型压电陶瓷驱动器来实现波长的电动调谐,实验获得了1.35nm的波长调谐范围,证实了所制785nm便携式光栅外腔可调谐半导体激光器适合作为便携式移频激发拉曼光谱检测系统的光源用于减除原始拉曼光谱中的荧光背景。     

A Continuously Tunable Erbium-Doped Fibre Laser Using Tunable Fibre Bragg Gratings and Optical Circulator

A continuously tunable erbium-doped fibre laser （TEDFL） based on tunable fibre Bragger grating （TFBG） and a three-port optical circulator （OC） is proposed and demonstrated. The OC acts as a 100%-reflective mirror. A strain-induced uniform fibre Bragger grating （FBG） which functions as a partial-reflecting mirror is implemented in the linear cavity. By applying axial strain onto the TFBG, a continuously tunable lazing output can be realized. The wavelength tuning range covers approximately 7.00nm in C band （from 1543.6161 to 1550.3307nm）. The side mode suppression ratio （SMSR） is better than 50 dB, and the 3 dB bandwidth of the laser is less than 0.01 nm. Moreover, an array waveguide grating （AWG） is inserted into the cavity for wavelength preselecting, and a 50 km transmission experiment was performed using our TEDFL at a 10 Gb/s modulation rate.     

Development of a dual-wavelength dye-laser system for the UV and its application to simultaneous multi-element detection

In this paper, the design and performance characteristics of a pulsed tunable dye laser system for the simultaneous generation of two UV wavelengths are presented. The system is composed of an oscillator and an amplifier stage, pumped by the second harmonic of a commercial Nd:YAG laser. Dual-wavelength operation is achieved with one additional tuning mirror introduced to the prism expanded grazing incidence oscillator. The two obtained wavelengths are independently tunable, their separation is only limited by the gain profile of the dye. Both wavelengths are frequency doubled by Second-Harmonic Generation (SHG) in two KDP or BBO crystals. Performance characteristics such as bandwidth, efficiency, tuning range and wavelength separation are reported. As application two such systems are used for the simultaneous detection of the four elements cadmium, nickel, manganese and lead by Laser-Excited Atomic Fluorescence Spectrometry in a graphite furnace (ETA-LEAFS).     

Single polarization, single transverse mode, and widely tunable narrow-linewidth laser from a multimode vertical cavity surface-emitting laser by use of a coupled cavity

A simple method for achieving a widely tunable narrow-linewidth, single polarization state and single transverse mode lasing oscillation from a commercially available multimode vertical cavity surface-emitting laser by use of a coupled cavity is reported. The laser has a wavelength tuning range of more than 5 nm along 850 nm, a side-mode suppression ratio of approximately 15 dB, and an output power of approximately 0.3 mW from a 50-microm multimode optical fiber at a bias current of 15 mA. The laser was operated in a single state of polarization lasing oscillation without any polarization switching.