光纤光栅外腔反馈的高功率半导体激光器光谱特性的研究

对光纤光栅外腔反馈的高功率半导体激光器的光谱线宽特性进行了理论与实验研究。理论分析表明，根据不同的外腔参数，激光器的线宽能被压缩或展宽。外腔反射率对光谱线宽的影响要比外腔腔长灵敏得多。实验实现了激光器的线宽由６ｎｍ到０．８ｎｍ的压缩。光纤光栅外腔反馈不仅能改善高功率半导体激光器的光谱特性，而且可提高激光器主模对次模的抑制比。     

Design of Balanced Dual‐Band Bandpass Filter with Self‐Feedback Structure

A balanced dual‐band bandpass filter based on λ/2 stepped‐impedance resonators and open‐loop resonators is proposed in this letter. By employing a type of self‐feedback structure, an extra transmission zero is introduced near the common‐mode resonance frequency, and the common‐mode signal is suppressed. The measured results indicate that the filter can operate in 2.46 GHz and 5.6 GHz bands, and the insertion loss is 1.85 dB and 1.9 dB, respectively. Also, better common‐mode suppression is achieved.     

Proposal for an All-Optical Flip-Flop Using a Single Distributed Feedback Laser Diode

We introduce a new concept for an all-optical flip-flop based on a single distributed feedback laser. The injection of external light into the laser results in a nonuniform carrier distribution. We will show numerically that this nonlinear effect of the carriers gives rise to a bistability that can be exploited for fast flip-flop operation.     

Proposal and Analysis of Distributed Reflector‐Laser Diode Integrated with an Electroabsorption Modulator

A novel integrated laser, that is, a distributed reflector laser diode integrated with an electroabsorption modulator, is proposed to improve the output efficiency, single‐mode stability, and chirp. The proposed laser can be realized using the selective metalorganic vapor phase epitaxy technique (that is, control of the width of the insulating mask), and its fabrication process is almost the same as the conventional electroabsorption modulated laser (EML) process except for the asymmetric coupling coefficient structure along the cavity. For our analysis, an accurate time‐domain transfer‐matrix‐based laser model is developed. Based on this model, we perform steady‐state and large‐signal analyses. The performances of the proposed laser, such as the output power, extinction ratio, and chirp, are compared with those of the EML. Under 10‐Gbps NRZ modulation, we can obtain a 30% higher output power and about 50% lower chirp than the conventional EML. In particular, the simulation results show that the chirp provided by the proposed laser can appear to have a longer wavelength side at the leading edge of the pulse and a shorter wavelength side at the falling edge.     

长腔长体布拉格光栅外腔半导体激光器

为了实现体布拉格光栅外腔半导体激光器(VBL)的外腔腔内光束合成,研究了长腔长VBL的激光输出特性。采用焦距为25 mm的平凸柱透镜作为单管激光二极管(LD)的慢轴准直镜,同时快轴方向体布拉格光栅(VBG)离轴放置,使得VBL的外腔腔长达到约240 mm,线宽从自由运转时的1.8 nm压窄至0.14 nm。在实验中,改变LD的偏振特性,VBL的激光输出特性不变。通过调节VBG温度,该长腔长VBL的激光中心波长从779.18 nm到779.75 nm连续可调,调谐过程中线宽基本不变。     

Monolithic Integration of a Waveguide Optical Isolator With a Distributed Feedback Laser Diode in the 1.5- μm Wavelength Range

We present first monolithic integration of a waveguide optical isolator with a distributed feedback laser diode (DFB LD) in the 1.5-mum wavelength range. The integrated devices are composed of 0.25-mm-long index-coupled DFB LDs and 0.75-mm-long semiconductor active waveguide optical isolators. The semiconductor active waveguide optical isolators are based on the nonreciprocal loss in the semiconductor optical amplifier (SOA) waveguides with ferromagnetic metals (Fe). The fabrication process consists of two steps of metal-organic vapor phase epitaxy to grow the DFB LD/SOA layer structures, one dry-etching process for the waveguide stripe formation, and three steps of electron-beam evaporation for the electrodes and ferromagnetic metals deposition. They showed single-mode emission at 1543.8nm and 4-dB optical isolation under a magnetic field of 0.1 T.     

半导体激光微小振动实时反馈式干涉测量仪

提出了一种带有反馈系统的半导体激光正弦相位调制干涉仪。该干涉仪可以实现对微小振动的高精度实时测量。通过一个简单的信号处理系统对干涉信号进行分析 ,获得实际振动的振幅和频率。由于引入反馈系统 ,减低了测量误差 ,排除了环境噪声的影响。给出了具体的理论分析和实验结果     

Dual-Wavelength InAlGaAs–InP Laterally Coupled Distributed Feedback Laser

The design and operation of a novel dual-wavelength laterally coupled (LC) distributed feedback (DFB) semiconductor laser are reported. The laser has two different grating periods, one on each sidewall. Stable dual-mode emission, with low threshold currents and good extinction ratio approaching 30 dB, has been demonstrated. Generation of millimeter-wave signals by photomixing has been performed, and the linewidths of each of the individual modes and of the beat mode have been measured as a function of the injection current. It is observed that while the linewidth of the separate modes has a modest dependence on the injection level, the linewidth of the beat mode experiences a strong decrease as the injected current increases     

Semiconductor Laser in Distributed Optical Feedback Regime

Wireless Personal Communications - In this work, we first analyse the behaviour of semiconductor laser in the presence of weak-to-moderate feedback from a single (lumped) and double external cavity...     

Maximum and Continuous Wavelength Tuning Ranges of a Grating External—cavity Laser Diode

The wavelength tuning rages of a grating external-cavity laser diode(ECLD)have been studied by the equivalent avity method.The maximum tuning range(MTR)and the continuous tunding range(CTR),which are related to the maximum and the minimum threshold carrier densities,are deduced from the threshold condition.We define a ratio of the CTR to the MRT.This ratio is only determined by the reflectivities of the external and internal facets of the ECLD.The analysis shows that there is an appropriate combination of the external and internalcavity reflectivites to obtain a given CTR in the design of an ECLD.     

用光纤光栅作外反馈的可调谐外腔半导体激光器

制作了一种以光纤光栅作为外反馈的半导体激光器。光纤光栅用紫外曝光法制作 ,反射率为 5 0 %。器件在5 0mA注入电流时 ,出纤功率高于 1mW ,主边模抑制比为 42dB。使用对光纤光栅施加应变和改变光栅温度的方法实现了输出激光波长的调谐 ,利用施加应变方法得到了 2nm范围的输出波长变化。     

Characteristics of Laser Cavity Solitons in a Vertical-Cavity Surface-Emitting Laser With Feedback From a Volume Bragg Grating

In this paper, the properties of laser cavity solitons (CS) in a vertical-cavity surface-emitting laser with feedback from a volume Bragg grating (VBG) are experimentally characterized. Independent optical manipulation of all eight possible bit states of three CS is demonstrated. Tilting the VBG provides evidence for different trapping states due to device disorder. The CS are found to “split” from a single peak to two peaks with increasing current, then to more complex arrangements, which are strongly governed by the spatial inhomogeneities. Due to the lack of any dominant polarizing elements, the system shows complex polarization behavior; however, each stage of the CS evolution has an approximately constant polarization angle unique for each CS. The polarization state of the CS can be controlled by adding polarization-selective or changing optics into the cavity.      

光纤光栅外腔半导体激光器特性的研究

对谐振式集成光学角速率传感器 IORS 的关键器件之一——大功率、窄线宽光源进行了分析与实验 .分析结果表明 ,为达到优于 1°/ h的分辨率 ,光源应选用线宽小于 1MHz的强反馈光纤光栅外腔半导体激光器 FBG- L D ;研究了 FBG- LD的单纵模机制和线宽压窄特性 ,着重考虑了反馈端面的残留反射率对 FBG- L D输出功率的影响 ,以及耦合效率对 FBG- L D线宽的影响 ;在实验研究中采用了大功率、窄线宽、单纵模的 FBG- L D,并应用于光纤谐振腔 ,实测的谐振腔的清晰度与理论计算值是一致的 .     

外腔反馈半导体激光器的损耗和阈值特性研究

通过对半导体激光器(LD)的损耗和阈值电流特性的分析，引入等效反射系数的概念，根据多光束干涉的原理，导出了在外腔反馈作用下LD的阈值电流公式。从等效反射系数的推导可以看出，外腔的反馈相当于增大了LD一个端面的反射率，减小了损耗，从而使LD激光振荡的阈值降低。该公式在外腔长度和激光波长可以比拟的情况下能够准确地分析反馈注入对阈值电流的影响，但是在外腔长度远大于激光波长情况下不再适用。针对实验中外腔长度较大的情况，使用光功率的分析简化了理论模型，得出了与实验结果相吻合的结论，即外腔反馈注入使LD出光阈值电流明显降低。     

Design of a Fiber Bragg Grating External Cavity Diode Laser to Realize Mode-Hop Isolation

Recently, a unique approach has been reported in which optical signal degradation is suppressed by realizing mode-hop isolation. This paper analyzes the mode-hop isolation condition in fiber Bragg grating type external-cavity diode lasers (FBG-ECDL). As a result, it has become possible to determine whether mode-hop isolation could be achieved. Moreover, it was verified experimentally that the mode-hop isolation of FBG-ECDLs was actually achieved with this method. The analytical method described in this paper is very useful for designing the uncooled ECDLs whose mode-hop must be isolated.     

Thermal Characteristics of a Laser Diode Integrated on a Silica‐Terraced PLC Platform

A spot‐size converted Fabry‐Perot laser diode (LD) was flip‐chip bonded to a silica‐terraced planar lightwave circuit (PLC) platform to examine the effect of the silica terrace on the heat dissipation of the LD module. From the measurement of the light‐current characteristics, it was discovered that the silica terrace itself is not a strong thermal barrier, but the encapsulation of the integrated LD with an index‐matching polymer resin more or less deteriorates the heat dissipation.     

新型窄脉冲半导体激光器驱动电源的研制

研制了一种新型窄脉冲半导体激光器的驱动电源,包括驱动电路和温控电路两部分。驱动电路采用高速金属氧化物半导体场效应晶体管(MOSFET)作开关,为激光器提供一个重复频率高(0~50 kHz)、前沿快(2.2~4.9 ns)、脉宽窄(4.6~12.1 ns)、脉冲峰值电流大(0~72.2 A)的脉冲信号,且输出的激光脉冲波形平滑。对不同的激光器,改变电路中电源电压、电阻、电容参数,可获得不同的重复频率、前沿、脉冲宽度、脉冲峰值电流。温控电路采用高精度的比例积分微分(PID)温控,保证了激光器输出功率和中心波长的稳定。此激光器驱动电源不仅可作为一般高速、窄脉冲半导体激光器的驱动电源,也是大能量、窄脉宽的半导体激光器种子光源的理想驱动电源。     

光纤光栅作为外反馈的混合腔半导体激光器

利用一个一端镀有增透膜的Ｆ－Ｐ腔半导体激光器芯片和一段反射率为５０％的光纤光栅组合成一混合腔激光器，腔长约为２ｃｍ。在５０ｍＡ的偏置电流下，主边模抑制比为３７．６ｄＢ，出纤功率为１ｍＷ。并对这种结构的激光器进行了初步的理论分析