Highly reliable high-power 980-nm pump laser

We report on highly reliable, high-power, and high-performance 980-nm quantum-well laser chips and modules. Ridge waveguide laser diode chips with 750-mW output power and 500-mW fiber Bragg grating stabilized modules have been achieved and Telcordia-qualified. Long-term reliability tests show a very low failure rate of 400 FIT (failures in time) at 900-mA operating current or 500-mW module power. The kink-free fiber coupled module output power can be as high as 640 mW with grating stabilization, which produces very good wavelength stability and power stability. A further improved structure shows a record continuous-wave rollover chip power of 1.6 W for the 5-/spl mu/m-wide ridge waveguide laser diodes.     

Greater than 500-mW CW kink-free single transverse-mode operation of weakly index guided buried-stripe type 980-nm laser diodes

This is the first report of greater than 500-mW CW kink-free single transverse-mode operation of 980-nm laser diodes with a weakly index guided buried-stripe type structure. The device exhibited a kink-free level of 545 mW and maximum optical output power of over 650 mW limited by thermal saturation and showed no catastrophic optical damage, in addition, a currently on-going aging test at 350 mW optical output power at 50/spl deg/C has shown stable operation. Using a can-sealed LD, we also fabricated a co-axial type module with a two-lens system and a lensed-fiber. The coupling efficiency between the LD and a single-mode fiber was calculated to be approximately 78% and we have confirmed 300 mW kink-free fiber output operation. These figures are also the highest reported operation levels for 980-nm co-axial type modules.     

偏振可控制的单频DBR光纤激光器

利用直接写在掺铒光纤上的一对光栅提供光反馈构成谐振腔,研制出了DBR光纤激光器;采用偏振控制器调节输出光的偏振态,分别观察到了与2个光栅Bragg波长对应的单频激光输出.泵浦功率68.8mW时得到了4.3mW的激光输出.对其调制特性进行了研究.     

一种高性能环形可调谐光纤光栅激光器研究

研制了一种新型的高性能环形可调谐光纤光栅激光器。该激光器使用980nm LD作为泵浦源,使用长度为10. 8m的新型增益平坦掺铒光纤作为增益介质,采用可调谐光纤光栅滤波器进行波长调谐,调谐范围可达41nm (1528nm～1569nm) ,中心波长可精确调谐到C波段指定的ITU - T标准中心波长处, 3dB 带宽< 0. 08nm, 25dB带宽< 0. 2nm,波长稳定性优于0. 01nm,边模抑制比> 60dB。最大输出功率46. 94mW,功率稳定性优于±0. 02dB,阈值泵浦功率7. 3mW,斜率效率为39. 75%。并分析了不同腔长、不同输出耦合比对输出功率的影响。     

Multiple-quantum-well GaInAs/GaInAsP tapered broad-area amplifierswith monolithically integrated waveguide lens for high-powerapplications

A 1.48-μm tapered broad-area semiconductor laser amplifier with a monolithically integrated waveguide lens as demonstrated. The gain saturation characteristics of the tapered amplifier were examined. A maximum output power of 300 mW and a 3-dB saturation power of 200 mW under quasi-CW conditions were obtained from the amplifier without the waveguide lens. Output power of 200 mW was obtained with a broad emission spectrum of ~30 nm when the device was used as a superluminescent diode. The amplified output was focused to a single lobe by the monolithically integrated aspheric waveguide lens, which may be useful for efficient coupling of the output into a single-mode fiber     

低掺杂铒纤上分布反馈布拉格光纤激光器的制作

采用准分子激光器成功地在低掺杂普通铒纤上制作出5 cm的光纤光栅分布反馈布拉格(DFB)激光器,铒纤的峰值吸收率为5 dB/m,在100 mW,980 nm抽运光条件下,光纤激光器的输出功率为50μW,边模抑制比为50 dB。使用耦合模理论分析了一段5 cm带相移的分布反馈布拉格光纤激光器输出光强同腔内损耗及相移量的关系,计算结果表明,光纤腔内的损耗对激光器的输出具有非常重要的影响,大的损耗对应获得最大功率的光栅耦合强度相应减小,因此,在低掺杂铒纤上制作分布反馈布拉格激光器必须正确估计光纤激光器的腔内损耗,选择合适的光栅耦合强度,可以获得较大的输出功率。     

Design of 20 W fiber-coupled green laser diode by Zemax

We represent a design of a 20 W, fiber-coupled diode laser module based on 26 single emitters at 520 nm. The module can produce more than 20 W output power from a standard fiber with core diameter of 400 μm and numerical aperture (NA) of 0.22. To achieve a 20 W laser beam, the spatial beam combination and polarization beam combination by polarization beam splitter are used to combine output of 26 single emitters into a single beam, and then an aspheric lens is used to couple the combined beam into an optical fiber. The simulation shows that the total coupling efficiency is more than 95%.     

A widely tunable SOA-integrated DBR laser by combination of sampled and superstructure gratings

We report on the development of the first 30 nm tunable laser diode utilizing a front sampled grating-distributed Bragg reflector (SG-DBR) and a rear superstructure grating DBR (SSG-DBR). A high output power greater than 18 mW was achieved with superior longitudinal mode stability, as well as an overall power variation of less than 3 dB for the well-defined laser. Furthermore, lasers integrated with a semiconductor optical amplifier (SOA) enabled the output power to be controlled independently both by the active current and the SOA current, as well as achieving a maximum output power of 45 mW. The side-mode suppression ratio was in excess of 40 dB for all the 50 GHz spaced wavelength channels.     

基于光纤光栅谐振腔的双包层光纤激光器

理论分析了线型腔双包层光纤激光器的输出特性,包括光纤长度、光纤损耗及后腔镜反射率对激光输出功率和阈值泵浦功率的影响.设计了基于光纤光栅谐振腔的双包层光纤激光器,采用锥度光纤实现了泵浦模块与双包层光纤之间的低损耗连接,实现了全光纤化的掺Yb3 双包层光纤激光器,其阈值泵浦功率为300 mW,在泵浦入纤功率为17 W时达到了10.5 W的最大激光输出功率,斜率效率为62%.     

Wavelength Selector External Cavity Laser Diode by Fiber Switch

A Fabry–Perot laser diode coupled to a single-mode fiber Bragg grating has the ability to emit a single longitudinal mode. In this paper a wavelength selector source based on a mechanical fiber switch used to change the Bragg grating in front of the laser diode is investigated. The external laser wavelength is changed. Critical coupling exists between the two fiber ends of the switch, which leads to the creation of a parasitic cavity inside the laser cavity. The aim of this work is to optimize the coupling ends of a single-mode fiber switch with respect to coupling efficiency and afterward measure the laser output power variation and spectrum to check their optical feedback characteristics on the relative intensity noise. Typical emission performance is a power of −2.5 dBm with a SMSR of 43 dB and a RIN of −146 dB/Hz.     

基于光纤Bragg光栅的掺铒光纤激光器

研制了基于光纤Bragg光栅的掺铒单模光纤激光器。用 980nmLD作抽运源 ,在 1 56 μm波段获得了谱线宽为 0 1nm的激光输出。最大输出光功率为 1 73mW。输出功率稳定性为± 0 .0 2dB ,波长稳定性为 0 0 5dB。阈值抽运光功率为 7mW ,斜率效率为 3%。     

双光纤光栅法-珀腔可调谐窄线宽激光器

基于游标原理,利用一对自由谱宽(FSR)略有不同的光纤布喇格光栅法布里-珀罗腔(FBG-FP)作为模式选择器件,设计了一种新颖的环形腔光纤激光器。从理论和实验上研究了该激光器的特性。通过对可调谐FBG-FP应力调谐,在1552.240～1552.912 nm范围内,以96 pm为平均间距,获得了8个由固定FBG-FP的透射谱所确定的窄线宽稳定激光输出。8个输出波长的平均功率为-17.66 dBm,波动在0.7 dB范围内。当泵浦光的功率为95 mW的时候,输出信号的信噪比均大于50 dB。实验上每隔1 min用光谱分析仪(OSA)对输出光波长自动扫描,记录的输出光波长漂移在数皮米范围内,且功率的波动小于0.1 dB。这种可调谐的窄线宽光纤激光器在光纤通信和光纤传感方面有潜在的应用价值。     

High-power and highly reliable 1020-nm ridge waveguide laser diodes with small aspect ratio as a pumping source for praseodymium-doped fiber amplifiers

The structure of an asymmetrically expanded optical field normal to the active layer was applied to 1020-nm ridge waveguide laser diodes in order to increase their maximum kink-free output power and reduce the aspect ratio of the output beams. As a result, a kink-free output power of more than 400 mW and an aspect ratio of less than 2.5 were achieved by this structure. Good reliability was also obtained at an output power of 300 mW at 50/spl deg/C.     

全光纤型Er/Yb共掺光纤短腔激光器

报道了一种高输出功率、高斜率效率的短腔ErYb共掺杂光纤激光器。激光谐振腔由一段ErYb共掺杂单模光纤与一对布拉格反射波长相同的光纤布拉格光栅(FBG)组成。反射率为60%的光纤光栅用作光纤激光器谐振腔的输出,3dB带宽为016nm。反射率为99%的光纤光栅作为高宽带反射腔镜,同时作为抽运光输入端,3dB带宽102nm。以980nm激光二极管(LD)作抽运源进行实验。使用不同的抽运功率分别测量不同长度的ErYb共掺杂光纤,优化光纤激光器谐振腔得到的最佳长度仅为13cm。即选用13cmErYb共掺杂光纤作为增益介质来制作短腔ErYb光纤光栅激光器,最大输出功率可达11mW,输出功率稳定性<±001dB,抽运阈值功率为35mW,斜率效率为153%,测量其15522nm激光的输出光谱,25dB线宽为03nm,边模抑制比>60dB,波长稳定性为005nm。可用于密集波分复用(DWDM)系统。     

单频单偏振窄线宽光纤激光器及其放大研究

为了获得高功率单频单偏振窄线宽激光,对一个带单级放大结构的环形腔结构掺铒光纤激光器系统进行了研究。采用作为可饱和吸收体的未抽运掺铒光纤结合作为波长选择器的高反射率光纤布喇格光栅形成超窄带滤波器,在环形腔内加入光纤偏振控制器和具有高消光比的保偏环行器获得单偏振光。环形腔输出后进行单级光放大以提高输出激光光功率。获得了206mW激光输出,输出功率长时间稳定度达到1.4%。通过光纤延迟自外差线宽测试系统得到输出激光线宽小于500Hz,光纤激光器输出光偏振度长时间稳定在99.7%。结果表明,非保偏可饱和吸收体加光纤布喇格光栅结合部分保偏结构可产生单频单偏振窄线宽激光,激光放大对线宽有明显的展宽效果。     

Highly Narrow Linewidth, CW, All-Fiber Oscillator With a Switchable Linear Polarization

We present a fiber laser with a switchable state of linearly polarized output realized by inscribing point-by-point fiber Bragg gratings directly into the active core of a polarization-maintaining fiber. The compact all-fiber system exhibited a very narrow laser linewidth of ~13.5 pm (3.5 GHz), at a maximum continuous-wave output power of 188 mW. The optical signal-to-noise ratio was greater then 62 dB for both lasing polarizations. The robust system exhibited excellent long-term wavelength and laser linewidth stability.     

High efficient and narrow linewidth fiber laser based on fiber grating Fabry-Perot cavity

A high Er3+-doped narrow linewidth fiber laser based on fiber Bragg grating Fabry-Perot cavity was demonstrated. The spatial hole burning effect was restrained by a fiber Faraday rotator. Two short fiber Bragg grating Fabry-Perot cavities as narrow bandwidth filters discriminated and selected laser longitudinal modes efficiently. A stable single-frequency 1534.83 nm laser was acquired. Pumped by two 976 nm laser diodes and two-ended output, the fiber laser exhibited a 12 mW threshold. Total 39.5 mW output power and one end 22 mW output power were obtained at the maximum 145 mW pump power. Optical-optical efficiency was 27% and slope efficiency was 29.7%. The output power seemed to be saturated when pump power increased. The 3 dB linewidth of the laser was less than 7.5 kHz, measured by the delayed self-heterodyne method with 15 km monomode fiber. The high power narrow linewidth fiber laser can be used in high resolution fiber sensor systems.     

Switchable multiwavelength erbium-doped fiber laser with cascadedfiber grating cavities

We propose a new concept to produce switchable multiwavelength oscillations with a cascaded fiber Bragg grating overlapping cavity erbium-doped fiber laser. The laser can be designed to operate in multiwavelength or in wavelength switching modes. The different lines have different thresholds. For three-wavelength oscillation, the output powers are linear or piecewise linear functions of the input pump power. An output with a variation of only 1.5 dB has been achieved with an input pump power of 100 mW. For wavelength switching, three single-wavelength and two dual-wavelength operation regions have been obtained toy adjusting the input pump levels     

平均功率近2 W的被动锁模皮秒掺镱光纤激光器

报道了一个三级主振荡功率放大(MOPA)结构的瓦级皮秒光纤激光器.第一级利用半导体可饱和吸收镜(SESAM)和光纤光栅组成线性腔,构建了一个低功率的被动锁模掺Yb3+光纤激光器,其最大平均输出功率为9.2 mW,作为整个激光器的种子源;第二级采用单模掺镱光纤放大器对种子光进行预放大,得到108 mW平均输出功率;第三级采用带树状耦合器的双包层掺镱光纤放大器进行功率放大,获得了1.9 W平均输出功率.得到的脉冲脉宽36 ps,中心波长1064 nm,重复频率29.6 MHz,峰值功率1.8 kW,相应的单脉冲能量为61 nJ.实验中观察到种子源输出光谱中有一个凹陷,这是由于光纤光栅反射率过高并且带宽较窄引起的.     

High-performance 980-nm ridge waveguide lasers with a nearly circular beam

We report high-performance 980-nm ridge waveguide quantum-well lasers with extremely low vertical beam divergence of 13/spl deg/. A very small aspect ratio of 1.6 is obtained at high operating power of 900 mW. In addition to the more circular beam, low threshold, high efficiency, high characteristic temperature, and high output power of over 1.18 W are achieved. The fiber coupled output power can be as high as 680 mW with fiber Bragg grating stabilization. Excellent wavelength and power stability are also demonstrated.