Experimental and numerical study on AlGaInAs/AlGaAs distributed feedback lasers with GaInP gratings

Ridge-waveguide AlGaInAs/AlGaAs distributed feedback lasers with lattice-matched GaInP gratings were fabricated and their light-current characteristics, spectrum and far-field characteristics were measured. On the basis of our experimental results we analyze the effect of the electron stopper layer on light-current performance using the commercial laser simulation software PICS3D. The simulator is based on the self-consistent solution of drift diffusion equations, the Schrödinger equation, and the photon rate equation. The simulation results suggest that, with the use of a 80 nm-width p-doped Al_0.6GaAs electron stopper layer, the slope efficiency can be increased and the threshold current can be reduced by more than 10 mA.     

Spectral study of a 1.55 μm multimode FP semiconductor laser using the transmission-line laser model

Transmission-line laser modelling is a time-domain technique suitable for simulating large-signal dynamics and complex phenomena in semiconductor lasers. We show that the transmission-line laser model (TLLM) is capable of predicting optical spectra in excellent agreement with the measured spectra of a commercially available 1.55 m Fabry-Perot (FP) laser, providing that scattering centres are introduced to simulate the effect of discrete scattering in or near the active region. The same model is also able to accurately predict the light-current curve, the pulse-modulation response and the relative-intensity-noise spectra of the laser. Thus, the TLLM can be applied to design and optimize short-haul optical communication systems using these commercial FP lasers.     

Synchronization of chaotic semiconductor lasers by optical injection with random phase modulation

It is shown that identical synchronization of two chaotic semiconductor lasers can be achieved by injection of a common optical signal with randomly varying phase. An optical signal with randomly modulated phase is injected into two semiconductor lasers which have chaotic oscillations due to optical feedback. Strong correlation between complex intensity oscillations of the two lasers is observed even though the intensity of the common injection signal is constant. Characteristic properties of this type of synchronization are shown, in particular, the dependence of the synchronization threshold on the injection strength and the rate of phase modulation, and the dependence of the intensity correlation on the difference in phase of optical feedback.     

光纤激光器的偏振开关操作

本文阐述了采用光子注入法实现光纤激光器的偏振开关操作.这种新颖的全光开关器件具有极低的阈值(0.1μW).对操作机理、实验实现和器件特性.     

Chaos synchronization and communication of mutual coupling lasers ring based on incoherent injection

A chaos secure communication system of mutual coupling lasers ring based on incoherent optical injection is proposed, in which fine tuning of optical frequency is not required compared with other schemes based on coherent optical injection. Therefore the secure communication scheme is attractive for experimental investigation. The dynamics of semiconductor lasers in the coupling ring are examined. Numerical investigations indicate that zero lag synchronization can be achieved under equal coupling time and strength of mutual coupling. Furthermore, by chaos shift keying (CSK), secure communication is simulated with a random bit stream of 1.0 Gbit/s. The results confirm the possibility of applying incoherent schemes of mutual coupling lasers ring to realize chaotic secure communication.     

Diode lasers coupled to external resonators

This tutorial revíew is concerned with the properties of injection lasers operated with passive optical feedback. Thep-n junction laser characteristics relevant for operation in external cavities are summarized. The properties of diode lasers coupled to different types of external resonators are reviewed as well as experiments that incorporate passive feedback in monolithic integrated optical structures.     

Diffusion and waveguiding effects in twin-stripe injection lasers

The properties of the twin-stripe injection laser are examined as functions of two parameters governing diffusion and waveguiding effects in the device. The carrier diffusion rate, as determined by the ambipolar diffusion coefficient,D, is shown to influence the current range over which lasing action is maintained. The curvature of the nonlinear portion of the light-current characteristic of the device is also changed asD is altered. It is found that the relative strengths of the guiding mechanisms acting upon the optical field further influence the characteristics of the structure.     

Efficient adjustment of the RF parameters of directly modulated laser diodes with ‘RF’ light-current parameters

An efficient method of adjusting the RF parameters of directly modulated laser diodes (LDs) is presented. By using the light-current parameters estimated from initial RF measurements, the new bias and modulation currents are obtained self-consistently for the target extinction ratio and average optical power. Experiments performed using distributed feedback lasers show that this adjustment method works efficiently, bringing the initial RF parameters very close to the target values within a couple of iterations. This method can be useful in manufacturing where there is a need to adjust the RF performance of the direct-modulated LDs to a desired specification.     

Semiconductor laser bistable operation with an adjustable trigger

Hysteresis is demonstrated in the light output versus current characteristics of twin-stripe injection lasers subject to optical injection. The sensitivity of the device to optical injection is adjustable and allows an adjustable switch for bistable operation to be defined.     

自旋激光器的动力学特性及应用研究进展

在半导体激光器中引入自旋极化载流子是实现室温自旋电子应用的新途径,其超越了常规的磁阻效应。自旋极化载流子的注入导致自旋激光器具有丰富的动力学行为并展示出包括高频偏振振荡和偏振混沌动力学等特性,使其在保密光通信、量子计算、光信息处理和数据存储、可重构光互联以及生物医学传感等领域具有巨大的应用潜力。梳理了近年来自旋激光器的动力学特性及其应用研究进展。介绍了自旋激光器丰富的动力学行为及混沌演变机制;随后分析了自旋激光器的高频振荡特性;归纳了基于自旋激光器动力学特性的最新应用研究进展。在此基础上,展望了自旋激光器的发展趋势和面临的挑战,为相关领域的研究和工程应用提供参考。     

Multi-target ranging using an optical reservoir computing approach in the laterally coupled semiconductor lasers with self-feedback

We utilize three parallel reservoir computers using semiconductor lasers with optical feedback and light injection to model radar probe signals with delays. Three radar probe signals are generated by driving lasers constructed by a three-element laser array with self-feedback. The response lasers are implemented also by a three-element lase array with both delay-time feedback and optical injection, which are utilized as nonlinear nodes to realize the reservoirs. We show that each delayed radar probe signal can be predicted well and to synchronize with its corresponding trained reservoir, even when parameter mismatches exist between the response laser array and the driving laser array. Based on this, the three synchronous probe signals are utilized for ranging to three targets, respectively, using Hilbert transform. It is demonstrated that the relative errors for ranging can be very small and less than 0.6%. Our findings show that optical reservoir computing provides an effective way for applications of target ranging.     

Stability of Optically Injected Two‐State Quantum‐Dot Lasers

Simultaneous two‐state lasing is a unique property of semiconductor quantum‐dot (QD) lasers. This not only changes steady‐state characteristics of the laser device but also its dynamic response to perturbations. In this paper we investigate the dynamic stability of QD lasers in an external optical injection setup. Compared to conventional single‐state laser devices, we find a strong suppression of dynamical instabilities in two‐state lasers. Furthermore, depending on the frequency and intensity of the injected light, pronounced areas of bistability between both lasing frequencies appear, which can be employed for fast optical switching in all‐optical photonic computing applications. These results emphasize the suitability of QD semiconductor lasers in future integrated optoelectronic systems where a high level of stability is required.     

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。     

1.55-μm InGaAs/InGaAlAs MQW vertical-cavity surface-emitting lasers with InGaAlAs/InP distributed Bragg reflectors

High-performance InGaAs/InGaAlAs multiple-quantum-well vertical-cavity surface-emitting lasers (VCSELs) with InGaAlAs/InP distributed Bragg reflectors are proposed for operation at the wavelength of 1.55 μm. The lasers have good heat diffusion characteristic, large index contrast in DBRs, and weak temperature sensitivity. They could be fabricated either by metal-organic chemical vapor deposition (MOCVD) or by molecular beam epitaxy (MBE) growth. The laser light-current characteristics indicate that a suitable reflectivity of the DBR on the light output side in a laser makes its output power increase greatly and its lasing threshold current reduce significantly, and that a small VCSEL could output the power around its maximum for the output mirror at the reflectivity varying in a broader range than a large VCSEL does.     

InSb/InAsSb nanostructures for Mid-IR optoelectronics

The technique of preparation of nanostructures with InSb quantum dots in an InAs(Sb) matrix, emitting in the mid-IR range upon optical and injection pumping, by molecular beam epitaxy is considered and the structural and optical properties of these nanostructures are investigated. The characteristics of the first injection lasers based on III–V/II–VI hybrid heterostructures with InSb/InAs(Sb) quantum dots in the active region are reported.     

基于非相干光反馈与注入的级联混沌系统研究

提出了基于延迟非相干光反馈与非相干光注入的级联混沌同步方案,与相干方案相比,该方案不需要频率完全匹配.数值研究结果表明,在其他参量匹配的情况下,发送机与接收机能实现完全同步.通过混沌键控方法,实现了信息的编码与解码.由于该级联方案具有非相干,宽带宽和多信息点传输的特点,所以在物理实现上很有吸引力,在全光中继通信方面也存在着很大的潜力.     

Characteristics of the Phase Noise Correlation of Injection Locked Lasers for RF Signal Generation and Transmission

Theoretical and experimental results on phase noise characteristics of an optical radio-frequency generation and transmission system using heterodyne photo-detection and side band injection locking is reported. Optical phase noise correlation of the lasers is achieved by noise transfer from a modulated master laser. Our investigation takes into account phase noise enhancement in optical comb generation, injection dynamic, path delay, and fiber dispersion. Theoretical expressions are derived from an adiabatic approximation and compared with experimental measures.     

A novel structure of visible semiconductor lasers

Terraced substrate inner current stripe lasers emitting in the range of 750–780 nm are developed with very simple fabrication processes. The lasers have good performance of cw room temperature, linear light-current output over 30 mW per facet and maintain stable fundamental transverse and longitudinal mode of 2–4 times current threshold. The current threshold of 25 mA under cw room temperature operation has been achieved.     

半导体激光器混沌输出的延时特征和带宽

外腔延时特征和带宽是影响混沌激光应用的两个重要参量.本文将一个单路光反馈的半导体激光器输出的激光部分地注入到另一个双路滤波光反馈的半导体激光器中,从而构成一个具有外光注入的双路滤波光反馈半导体激光器系统,即主从激光器系统,用于抑制混沌激光的延时特征并研究其带宽.数值研究了外光注入系数、反馈强度、抽运因子和滤波器带宽对系统输出混沌激光的延时特征的影响,然后将该系统对延时特征的抑制效果和具有外光注入的单路光反馈半导体激光器系统、具有外光注入的双路光反馈半导体激光器系统、具有外光注入的单路滤波光反馈半导体激光器系统以及无光注入双路滤波光反馈半导体激光器系统进行对比和分析,结果表明本文提出的方案对延时特征的抑制效果最好.然后在本文提出的具有外光注入的双路滤波光反馈半导体激光器系统中,延时特征被有效抑制的参数条件下研究系统输出混沌激光的带宽,结果表明,通过适当选择参数的取值,本文提出的方案可以提高系统输出混沌激光的带宽.     

Synchronization properties and effects of parameter mismatches in unidirectionally coupled chaotic vertical-cavity surface-emitting lasers

We numerically investigate the effects of parameter mismatches on chaos synchronization in vertical-cavity surfaceemitting lasers (VCSELs). We assume injection-locked chaos synchronization in a unidirectionally coupled and openloop optical feedback system. The accuracy of chaos synchronization is greatly affected by the mismatches of the device parameters and operation conditions between the two lasers. In particular, the oscillation frequency of the laser is one of the important parameters in a system of injection-locked chaos synchronization. However, the variations of the device characteristics of VCSELs are very large compared with those of other types of semiconductor lasers. We study the effects of parameter mismatches related to the oscillation frequency of VCSELs on chaos synchronization. We proved that mismatches in terms of the birefringence and the injection current play crucial roles for the quality of chaos synchronization.