1.5μm波长范围的InGaAsP/InP分布反馈式激光器

<正> 日本KDD研究和发展实验室从理论上和实验上研究了1.5μm波长范围的InGaAsP/InP分布反馈式(DFB)激光器的激射特性。分析了5层DFB波导中波的传播,估算出结构参数对阈值条件的影响。在设计低阈值激光器及其激射波长方面进行了主要考虑。用液相外延方法制备了具有1.53μm发射主光栅的DFB隐埋异质结构激光器。在-20℃～58℃的温度范围内实现了CW工作。室温下的CW阈值电流低至50mA。在直流与500Mbit/s的伪随机脉冲电流     

1.78 μm应变InGaAs-InGaAsP-InP分布反馈量子阱激光器

采用低金属有机汽相外延(LP-MOVPE)生长大应变InGaAs/InGaAsP做有源区,研制了激射波长为1.78μm的脊波导分布反馈(DFB)激光器,对于解理腔长为900μm的激光器,室温时其激射的阈值电流为33mA,最大单面光输出功率/和单面外微分量子效率分别为8mW和7％;此外,激射光谱边模抑制比(SMSR)为27.5dB。     

MOCVD生长InGaAs/InGaAsP多量子阱光泵微碟激光器

用MOCVD方法生长了InGaAs/InGaAsP多量子阱微碟激光器外延片,用光刻、干法刻蚀和湿法刻蚀等现代化的微加工技术制备出直径9.5μm的InGaAs/InGaAsP微碟激光器,并详细介绍了整个制备工艺过程．在液氮温度下用氩离子激光器泵浦方式实现了低阈值光泵激射,测出单个微碟激光器的阈值光功率为150μW,激射波长约为1.6μm,品质因数Q=800,激射光谱线宽为2nm,同时指出微碟激光器激射线宽比F-P普通激光器宽很多是由于其品质因数很高造成的．     

1．7μm波长单频掺铥光纤激光器研制成功

最近，丹麦科技大学的科学家们研制成功被认为是第1个基于铥（Tm）离子的1．7μm波长、单频、分布反馈（DFB）的光纤激光器，他们期望该激光激射波长在1．7～2．1μm，将用于高分辨率光谱仪、相干光雷达和光频率混合等领域。     

全息光刻制备LC-DFB及光栅刻蚀优化（英文）

成功制备出室温激射波长为2μm的Ga Sb基侧向耦合分布反馈量子阱激光器.采用全息曝光及电感耦合等离子体刻蚀技术制备二阶布拉格光栅.优化了光栅制备的刻蚀条件,并获得室温2μm单纵模激射.激光器输出光功率超过5 m W,最大边模抑制比达到24 d B.     

MOCVD生长InGaAs/InGaAsP多量子阱光泵微碟激光器

用 MOCVD方法生长了 In Ga As/ In Ga As P多量子阱微碟激光器外延片 ,用光刻、干法刻蚀和湿法刻蚀等现代化的微加工技术制备出直径 9.5μm的 In Ga As/ In Ga As P微碟激光器 ,并详细介绍了整个制备工艺过程 .在液氮温度下用氩离子激光器泵浦方式实现了低阈值光泵激射 ,测出单个微碟激光器的阈值光功率为 15 0μW,激射波长约为 1.6μm,品质因数 Q=80 0 ,激射光谱线宽为 2 nm,同时指出微碟激光器激射线宽比 F- P普通激光器宽很多是由于其品质因数很高造成的     

InGaAsP/InP宽调谐有源Bragg反射集成半导体激光器

目前,由InGaAsP/InP双异质结构成的工作在1.3或1.55μm的半导体激光器由于适用于光纤通信系统,其可调单模激光器受到了人们日益的重视。因为不少实际应用场合都需要波长的调谐。一般,除了依靠器件的工作温度来达到少量的调节外、半导体激光器本身是不能调谐的。用带有可调光栅反射器的外腔结构,可以实现20-60nm的调谐范围,它只受到了激射材料增益光谱的限制。不用外部光学元件的单片集成激光器,调谐可以用多段式的分布反馈(DFB)或     

1．7μm波长单频掺铥光纤激光器研制成功

目前，世界上已研制出在1．1μm光波段掺镱（Yb）离子和1．5μm光波段掺铒（Er）离子的单频光纤激光器。最近，丹麦科技大学的科学家们研制成功被认为是第一个基于铥（Tm）离子的1．7μm波长、单频、分布反馈（DFB）的光纤激光器。他们期望该激光器激射波长在1．7—2．1μm，将用于高分辨率光谱仪、相干光雷达和光频率混合等领域。     

掺铒半导体注入式激光器:提高单纵模工作特性及其在1.55μm下的传输实验

<正> 美国Bell实验室的W.T.Tsang等人在第6届光纤通信-集成光学,光纤通信国际会议(OFC/IOOC,1987)上报导了一种掺铒半导体注入式新型激光器结构。这种新结构是利用在半导体激光器的有源层内掺有0.5％的稀土元素—铒,从而使稀土元素的原子能级跃迁产生的窄增益谱叠加在基质半导体的较宽增益谱之上,结果稀土跃迁波长下的增益很高,首先克服腔损耗而达到激射作用。在1.55μm波长下,腔长250μm激光器的纵模间隔为     

Single Mode Operation of Short-Cavity Quantum Cascade Lasers

报道了激射波长为5.4和7.84μm的应变补偿In1-xGaxAs/In1-yAlyAs量子级联激光器的单模激射.以高质量的应变补偿量子级联激光器材料为支撑,通过减小FP腔长,开辟实现单模器件的新途径.首次实现阈值电流仅为50mA、腔长为145μm的激射波长在λ≈5.4μm的单模激射和阈值电流仅为80mA、腔长为170μm的激射波长在λ≈7.84μm的单模激射.这是目前InGaAs/InAlAs材料体系最短腔长的边发射量子级联激光器.     

Analysis of a wavelength selectable cascaded DFB laser based on the transfer matrix method

A novel cascaded DFB laser,which consists of two serial gratings to provide selectable wavelengths,is presented and analyzed by the transfer matrix method.In this method,efficient facet reflectivity is derived from the transfer matrix built for each serial section and is then used to simulate the performance of the novel cascaded DFB laser through self-consistently solving the gain equation,the coupled wave equation and the current continuity equations.The simulations prove the feasibility of this kind of wavelength selectable laser and a corresponding designed device with two selectable wavelengths of 1.51μm and 1.53μm is realized by experiments on InP-based multiple quantum well structure.     

Longitudinal mode behaviors of 1.5 µm range GaInAsP/InP distributed feedback lasers

Longitudinal mode behaviors of asymmetric structure distributed feedback buried heterostructure (DFB-BH) lasers are examined theoretically and experimentally. A 1.5 μm range GaInAsP/InP DFB-BH laser was fabricated by a three-step LPE growth process. We measured the stopband in the spectrum of the DFB laser. It was found that no resonance mode emission occurred in the gain spectrum and its spectrum was asymmetric with respect to the Bragg wavelength. Most of the lasing power concentrated on the DFB mode adjacent to the stop-band which was determined by the Bragg condition. The measured spectrum was explained by the calculated results of the coupled wave theory with external reflectors. The asymmetric spectrum was caused by the relative position of the cleaved facet on the corrugation grating. It was shown that the asymmetric structure DFB laser, which consisted of two end facets with different reflection coefficients, gives a stable single longitudinal mode. There was no mode jump up to 2.3 times threshold. At a modulation depth of 100 percent, the ratio of the highest nonlasing mode intensity to the lasing DFB mode was estimated to be -16.0 dB.     

Dual-Wavelength DFB Fiber Laser Based on Unequalized Phase Shifts

A novel structure for dual-wavelength distributed feedback (DFB) fiber laser is proposed and experimentally demonstrated. This structure is based on a uniform fiber Bragg grating with two unequalized phase shifts, which markedly suppress the mode competition of the two lasing wavelengths; and then a 52-pm-spaced dual-wavelength DFB fiber laser operating at single-longitudinal-mode and single-polarization is achieved at room temperature. A simple method is also implemented to fabricate the phase shifts with high precision     

Optical frequency spacing tunable four-channel integrated 1.55 mu m multielectrode distributed-feedback laser array

A four-channel integrated 1.55- mu m multielectrode distributed-feedback (DFB) laser array was fabricated using the metallorganic vapor-phase deposition/liquid-phase epitaxy (MOVPE/LPE) hybrid method. Simultaneous single-longitudinal mode operation was achieved in each multielectrode DFB laser on a single chip. Utilizing the frequency tunability of multielectrode DFB lasers, optical frequency spacings were controlled and set to within a few gigahertz. The drift of frequency spacings due to temperature fluctuation was in the range of +or-50 MHz for temperature control of +or-0.1 degrees .<>     

多功能红外焦平面读出电路设计

主/被动成像系统具备多种成像模式,集成度高、成本低、系统运行效率高,应用前景良好。设计了一种64×64规模的多功能红外焦平面阵列读出电路,在30 μm像元中心距的限制下实现了日光标准成像、微光成像、异步激光脉冲检测和二维激光测距四种成像功能。基于TSMC 0.35 μm工艺,完成了多功能读出电路的芯片设计与流片验证。电路复用设计和像素共享架构显著降低了版图面积。CTIA的T型开关有效减小漏电流,改善了红外被动成像电路的动态范围,高增益模式下动态范围达60 dB,低增益模式下动态范围达68 dB。并且满阱电荷容量分别为203 ke?和1.63 Me?。三级push-pull运放和MOS反馈电阻使RTIA兼具高增益和小尺寸。芯片测试结果表明,电路具备主/被动成像功能,性能良好,可应用于红外焦平面激光雷达成像系统。     

Detuning adjustable multiwavelength MQW-DFB laser array grown byeffective index/quantum energy control selective area MOVPE

A multiwavelength MQW DFB laser array with novel structure Is described. Oscillation wavelength and gain peak wavelength were simultaneously controlled on the same epitaxial wafer by using modulated grown thicknesses of selectively grown InGaAs/InGaAsP/InP MQW active waveguides. The laser array with constant-pitch built-in corrugation fabricated by a simple DFB laser process demonstrated 10.1 nm controllable range for lasing wavelength and 45 nm for gain peak wavelengths, with uniform lasing properties and narrow spectral linewidths. The technique is attractive for light sources used in WDM/FDM applications     

强增益耦合DFB激光器单片集成自对准模式变换器

提出并成功制作出一种新型的强增益耦合 DFB激光器与自对准模式变换器单片集成器件 .采用三次外延实现上述器件 .采用强增益耦合 DFB激光器 ,获得了高单模成品率和大边模抑制比器件 ;采用自对准模式变换器 ,得到了近圆形的远场图样     

Longitudinal spatial instability in symmetric semiconductor lasersdue to spatial hole burning

A novel type of longitudinal instability due to spatial hole burning in symmetric semiconductor laser structures (DFB lasers in particular) is examined analytically and numerically. It is shown that, at a certain output power, the gain and refractive index spatial distributions of the lasing mode become unstable. Above this output power, the modal gains and oscillation frequencies change drastically, which often causes multimode operation. A measure of the cavity stability is introduced and derived analytically for a Fabry-Perot and a single phase-shifted DFB laser. Results from numerical simulations of a multiple phase-shifted DFB laser are presented     

Distributed feedback InGaAsP/InP lasers with window region emitting at 1.5 µm range

Distributed feedback (DFB) InGaAsP/InP lasers with a window region formed at an end of the corrugated DFB region were made in order to overcome the problems inherent in the previous structures of DFB lasers with cleaved, sawed, etched, or AR-coated facets, or with an unexcited corrugation region. The window structure DFB lasers showed linear current versus output (I-L) curves, in contrast to those with a hysteresis or a kink appearing in a DFB laser with an unexcited region. Suppression of Fabry-Perot (F-P) resonances due to the two facets were sufficient enough to keep a single longitudinal mode property by DFB up to high excitation level. CW operation up to 65°C was achieved at the 1.5 μm wavelength range. Axial modes concerning the corrugated resonator were measured at about the threshold current. A stop band of a DFB laser was clearly observed with two dominant modes and much smaller submodes, which almost agreed with the axial modes predicted from a basic DFB theory.     

A 1.54-μm monolithic semiconductor ring laser: CW andmode-locked operation

The authors have fabricated a monolithic semiconductor ring laser with a diameter of 3.0 mm. A straight tangent waveguide provides two output ports through evanescent coupling. The laser, which exhibits a threshold current of 157 mA, operates in a single longitudinal mode with a linewidth of 900 kHz at a wavelength of 1.54 μm. The device has been actively mode-locked at the fundamental resonance frequency of 9.0 GHz, yielding 27-ps pulses with a time-bandwidth product of 0.47. Differences in the characteristics of the pulses emitted from the two output ports indicate counterpropagating pulse trains, which because of the mode-locking scheme must collide in the modulated gain section