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1.
A new technique for analyzing the single-mode condition and mode discrimination of high-order modes in photonic crystal VCSEL
is proposed and reported in this paper. The technique proposed is a semi-empirical approach that uses analytical analysis
based on experimental data. For that purpose, single- and multimode photonic crystal VCSEL devices are fabricated and characterized
for comparison of device performance. The mode width for first- and second-order mode of PhC VCSEL is computed for analyzing
the mode behavior. In order to verify the findings, the fabricated single- and multimode devices are analyzed using finite
difference frequency domain technique for the purpose of showing the loss as a function of mode order for the PhC VCSEL. The
results show close agreement between the computed and experiment findings, justifying the use of the proposed semi-empirical
technique for analyzing single-mode condition and of high-order modes discrimination in photonic crystal VCSEL. 相似文献
2.
Excitation of various transverse modes in possible nitride vertical-cavity surface-emitting lasers (VCSELs) is investigated and compared using the effective frequency optical model. In the comparative analysis of laser mode selectivity, two distinctly different configurations of possible nitride VCSELs are considered: the traditional VCSEL design with both (n-side and p-side) ring contacts as well as the uniform-current-injection (UCI) VCSEL design. Our simulation reveals that, during the continuous-wave device operation at room temperature, a multi-mode operation dominated by higher-order transverse modes is typical for traditional nitride VCSEL configurations whereas a desirable single-mode (based on the fundamental LP01 mode) operation turns out to be characteristic for the wide current range in UCI ones. The above different threshold device behaviours are an immediate consequence of essentially different current-spreading phenomena in both VCSEL designs, resulting in completely different not only gain profiles but also temperature distributions within the laser active regions of both VCSELs. Seemingly similar behaviour has been also reported in arsenide VCSELs but it is expected to be much more severe in the case of nitride ones as a result of much higher both electrical resistivities of p-type nitrides and their temperature derivatives of refractive indices. 相似文献
3.
We have investigated the lasing modes of oxide-confined vertical-cavity surface emitting lasers (VCSELs). The individual Laguerre–Gaussian modes have been spectrally and spatially resolved with scanning confocal microscope with time resolution of 4 ps. Subject to the injection of ultrafast laser pulses, the VCSEL showed irregular pulsed emission which indicates the potential for transverse mode-locking of the VCSEL. 相似文献
4.
A theoretical analysis of the polarization and transverse modes of Vertical-cavity Surface-emitting lasers with external optical
injection is performed. We show that, for single-mode operation, weak injection of linearly polarized light can lead to stable
output power in the injected polarization. We also show that, for multitransverse mode operation, weak injection of linearly-polarized
light can lead to stable emission of the fundamental transverse mode in the injected polarization over wide current ranges.
The previous selection can occur when the transverse modes have parallel or orthogonal polarizations. 相似文献
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A multi-hole vertical-cavity surface-emitting laser(VCSEL) operating in stable single mode with a low threshold current was produced by introducing multi-leaf scallop holes on the top distributed Bragg-reflector of an oxidationconfined 850 nm VCSEL.The single-mode output power of 2.6 mW,threshold current of 0.6 mA,full width of half maximum lasing spectrum of less than 0.1 nm,side mode suppression ratio of 28.4 dB,and far-field divergence angle of about 10 are obtained.The effects of different hole depths on the optical characteristics are simulated and analysed,including far-field divergence,spectrum and lateral cavity mode.The single-mode performance of this multi-hole device is attributed to the large radiation loss from the inter-hole spacing and the scattering loss at the bottom of the holes,particularly for higher order modes. 相似文献
9.
A multi-hole vertical-cavity surface-emitting laser (VCSEL) operating in stable single mode with a low threshold current was produced by introducing multi-leaf scallop holes on the top distributed Bragg-reflector of an oxidation-confined 850 nm VCSEL. The single-mode output power of 2.6 mW, threshold current of 0.6 mA, full width of half maximum lasing spectrum of less than 0.1 nm, side mode suppression ratio of 28.4 dB, and far-field divergence angle of about 10° are obtained. The effects of different hole depths on the optical characteristics are simulated and analysed, including far-field divergence, spectrum and lateral cavity mode. The single-mode performance of this multi-hole device is attributed to the large radiation loss from the inter-hole spacing and the scattering loss at the bottom of the holes, particularly for higher order modes. 相似文献
10.
为了分析质子轰击垂直腔面发射激光器(VCSEL)中注入电流引起的激光模式竞争过程,在三维空间中对VCSEL激射后光电热进行了研究。给出仿真光电热的方程之后,在室温连续工作条件下,对电流孔半径r为4μm、阈值电流Ith为4.5 m A的VCSEL进行自洽求解。当注入电流Iin分别为5.0,5.5,6.0 m A时,得到了对应的外加电压和输出光功率,并绘制了VCSEL的电势、注入电流、载流子、光场和热场的空间分布,给出了连续工作下输出光功率随注入电流变化的曲线。仿真结果表明:随着注入VCSEL中的电流增加,电流密度增大,激光的横向基模和横向一阶模式同时增强。横向一阶模式增加的强度及扩展的范围大于横向基模,激光输出能量逐渐向横向一阶模式过渡,横向模式竞争的同时产生载流子空间烧孔,因此在电流孔半径r≥4μm的VCSEL中,连续工作激光模式不稳定。 相似文献
11.
We theoretically investigate the synchronization performance of the polarization modes of two unidirectionally coupled vertical-cavity surface-emitting lasers (VCSELs), where the master VCSEL subjects to polarization-preserved optical feedback and the slave VCSEL subjects to polarization-preserved optical injection. We demonstrate that high synchronization can be achieved between corresponding polarization components of the master laser and the slave laser. We also analyze the influence of the internal mismatched parameters on the synchronization performance. Furthermore, this system is used to dual-channel communication and the different transmitted digital information is respectively recovered at each polarization branch of the slaver laser successfully with the encryption scheme of chaos masking (CM). The results open an opportunity for multichannel chaotic communication by utilizing different polarization components in single-mode or multi-transverse-mode VCSELs. 相似文献
12.
M. S. Alias S. Shaari P. O. Leisher K. D. Choquette 《Applied physics. B, Lasers and optics》2010,100(3):453-459
In this letter, we report on single-mode operation of originally multi-mode oxide VCSEL by using etched photonic crystal air
holes and unique trench structure. The device fabrication utilized conventional photolithography; with simplified lithography
step of self-aligning the photonic crystal and trench structures to the laser aperture for efficient and vigorous device processing.
The fabricated photonic crystal VCSEL with trench device exhibits a single-mode output power of 0.7 mW, threshold current
of 3.5 mA, slope efficiency of 0.10 W/A, and continuous single-mode output spectra at wide operating current range. The results
are compared with conventional multi-mode oxide VCSEL of similar device geometry. In addition, theoretical analysis is presented
for developing further understanding of the photonic crystal VCSEL. 相似文献
13.
The dynamics of radiation of a vertical cavity surface emitting laser (VCSEL) has been simulated numerically under the conditions of a pseudorandom sequence of the pumping current pulses. The influence of diffusion and spatial burning of holes in the carrier concentration distribution in the active layer on the competition of the transverse modes of the VCSEL has been investigated. 相似文献
14.
在最近的实验和理论研究中,我们探讨了氩原子和氖原子在红外强激光场中低于再碰撞阈值的非序列双电离问题。在研究中,我们发现在非序列双电离过程中,氖原子的电子关联表现为在激光偏振面内肩并肩出射,而对于氩原子的电子关联行为表现为在激光偏振面内的背对背出射,我们采用三维半经典模型(考虑电子隧道电离)很好地解释了实验结果。在阈值附近,我们发现电子在激光场中的多次散射以及电子再碰撞激发后电子隧道电离是氩原子反关联行为的主要原因,而电子在激光场作用下的单次碰撞是电子关联行为的主要原因。通过测量双电离过程中产生电子的横向电子动量分布,观察到了库伦聚焦效应,我们认为这是非经典的关联行为。最后,我们给出了氩原子和氖原子在激光场中阈值的解析模型,并给出了原子的关联和反关联激光强度区域. 相似文献
15.
Using a theoretical semiclassical approach, we study in detail the amplitude fluctuations and correlations of a two-orthogonal polarization-mode semiconductor laser as obtained from a vertical-cavity surface-emitting laser (VCSEL). We demonstrate that there exists the possibility of squeezing in the two-mode regime besides sub-shot-noise emission in the well-known ideal single-mode operation regime. These theoretical results confirm a recent experimental demonstration of the generation of amplitude-squeezed light with VCSEL's. 相似文献
16.
Botao Zhang 《Optics Communications》2011,284(12):3011-3013
Single-mode vertical-cavity surface-emitting lasers (VCSELs) have been investigated with ultrafast optical modulation. After injection of a subpicosecond laser pulse into the VCSEL cavity, nonlasing modes were excited and produced optical beating in the emission of the VCSEL. After these oscillations have died down, when the VCSEL is operating at high power and when the injected laser pulses exceed a power threshold as well, the injected laser pulses can induce the lasing to switch to a normally nonlasing mode with crossed polarization. Our measurements of the decay time of the nonlasing modes at low injected pulse energy are consistent with the interpretation of this switching as enabled by increased lifetime of the nonlasing modes at high power. 相似文献
17.
Hongbin Zhang 《International Journal of Infrared and Millimeter Waves》2007,28(9):713-723
A spatially independent model of vertical-cavity surface-emitting lasers (VCSELs) is derived by integrating the spatially
dependent rate equations over the cross section of the cavity of a VCSEL. The angular and radial non-uniformities of the injection
current are taken into account. The well-known LP modes of a weakly-guiding cylindrical waveguide are employed to describe
the transverse modal structure in the VCSEL cavity. This model is solved in a self-consistent way by using the 4th order Runge-Kutta
method. The dependence of transverse mode competition on the current intensity, the angular and radial non-uniformities of
the injection current, and the geometrical parameters of the electrical contact are thoroughly investigated and analyzed.
The results are useful to the optimum design of the optical transverse modal structure of VCSELs. 相似文献
18.
在最近的实验和理论研究中,我们探讨了氩原子和氖原子在红外强激光场中低于再碰撞阈值的非序列双电离问题。在研究中,我们发现在非序列双电离过程中,氖原子的电子关联表现为在激光偏振面内肩并肩出射,而对于氩原子的电子关联行为表现为在激光偏振面内的背对背出射,我们采用三维半经典模型(考虑电子隧道电离)很好地解释了实验结果。在阈值附近,我们发现电子在激光场中的多次散射以及电子再碰撞激发后电子隧道电离是氩原子反关联行为的主要原因,而电子在激光场作用下的单次碰撞是电子关联行为的主要原因。通过测量双电离过程中产生电子的横向电子动量分布,观察到了库伦聚焦效应,我们认为这是非经典的关联行为。最后,我们给出了氩原子和氖原子在激光场中阈值的解析模型,并给出了原子的关联和反关联激光强度区域。 相似文献
19.
We report a tunable, single-mode vertical cavity surface-emitting laser (VCSEL) format suitable for array operation, power scaling, fiber coupling, and operation in isolated environments such as those required by atom optics. The devices are fiber VCSELs, consisting of a semiconductor gain and mirror structure separated from a mirror-coated optical fiber by an air (or vacuum) gap. The gain structure has polymer microlenses fabricated on its surface, of characteristics suitable to focus the oscillating mode on both cavity mirrors, ensuring stable fundamental mode emission and high fiber coupling efficiency. We demonstrate such devices in continuous-wave operation at 1.03 microm at room temperature, with a single-mode tuning range of 13 nm, laser threshold as low as 2.5 mW, and a maximum fiber-coupled output power of 10 mW. 相似文献
20.
?ukasz Piskorski Robert P. Sarza?a W?odzimierz Nakwaski 《Applied Physics A: Materials Science & Processing》2010,98(3):651-657
Minimal optical attenuation of plastic (polymer) optical fibres (POFs) corresponds to the 650-nm wavelength. Currently the
GaInP/AlGaInP quantum-well (QW) oxide-confined (OC) vertical-cavity surface-emitting diode lasers (VCSELs) are undoubtedly
the laser devices most suited to be used in 650-nm POF optical communication, for which the stable single-fundamental-mode
LP01 emission (SFM) is definitely the one most desired. In the present paper, the comprehensive fully self-consistent VCSEL model
is used to examine mode selectivity of the above VCSELs. An increase in the VCSEL active-region diameter leads to a gradual
modification of the current injection into this region and subsequent carrier radial diffusion within it before their recombination,
which is followed by an essential transformation of active-region optical-gain profiles deciding upon an excitation of successive
transverse modes. In standard arsenide OC VCSELs, SFM operation is usually limited to relatively small active regions. But
for a room-temperature continuous-wave operation of the GaInP/AlGaInP VCSELs, the fundamental LP01 mode remains surprisingly the lowest-threshold one up to relatively large active regions of 9-μm diameters. Nevertheless,
in such VCSELs, thresholds of many LP modes become very similar to one another, which leads to their relatively poor mode
selectivity and an unwanted multi-mode operation for higher output powers. 相似文献