褶皱衍射光栅提升绿光量子点发光二极管的光耦合输出效率

为了解决绿光量子点发光二极管(QLED)基底模式陷入光问题,首先通过在柔性聚二甲基硅氧烷基底上蒸镀铝层,自发形成了准周期褶皱结构。这种简单、有效的方法可以制作大面积的褶皱结构,所制作的褶皱结构具有随机取向和宽周期分布的特点。然后,将褶皱结构作为外结构引入到QLED中,构筑了高效的绿光QLED。与参考QLED相比,褶皱QLED的外量子效率(EQE)从12.09%增加到16.06%,提升了32.8%;最大亮度从184600cd·m^(-2)增加到226500cd·m^(-2),在不改变发光峰位的情况下实现了基底模式陷入光的高效提取,为提升绿光QLED性能提供了一种新的选择。

用于光催化反应器的双面出光LED光源设计

从光催化反应器的光源结构出发,采用波长为365 nm的紫外2835LED作为光源。使用基材为PMMA并分别掺入二氧化硅和氧化铝晶体颗粒的亚克力板作为纳米导光板。利用建模工具Solidworks及仿真工具Lighttools设计导光板双面出光模型,并进行仿真优化。仿真结果表明,当导光板尺寸为600 mm×300 mm×4 mm,采用氧化铝纳米晶粒的粒子数密度为3 450 mm^(-3),粒径为2 150 nm时,紫外光光耦合效率在70%以上,双面出光光照均匀度均在80%以上,符合光催化反应器光源的要求。

一种新型可见光无线通信可调复眼光学接收系统

在可见光无线通信系统中,接收端需具备小型化、大视场、高增益等特点。本文设计了一种基底可活动、由塑料光纤代替晶椎的复眼结构光学接收系统。和传统复眼透镜相比,最大视场角增加了92°。光纤代替晶椎使得光损耗降低了0.3457dB,实现了可见光无线通信接收端大视场、高增益的目的。

用于空间光信号接收的指数型特种光锥耦合效率分析与测试

在无线光通信中，外界复杂的环境很容易造成光束的偏转，从而影响其光接收效率。针对这一问题，提出一种指数函数型特种光锥作为空间光信号光接收装置。它是由纯净玻璃材料制成的，母线形状将直接影响其光接收性能。研究并推导了特种光锥的母线方程，然后基于射线光学理论，分析了特种光锥内部光线轨迹和在小端面的出射光能量，并且搭建了实验装置，进行了耦合效率的测试，并对其误差进行了分析。实验结果表明，指数型特种光锥曲线与理论结果基本一致，其大端面接收范围可达6.8 mm，耦合效率最高可达57%，可用于无线光通信、光纤通信、光束耦合等场合的光信号接收。

Influence of positioning errors of optical shaping components for single emitter laser diode on beam shaping effects

Beam shaping is required for semiconductor lasers to achieve high optical fiber coupling efficiency in many applications.But the positioning errors on optics may reduce beam shaping effects,and then lead to low optical fiber coupling efficiency.In this work,the positioning errors models for the single emitter laser diode beam shaping system are established.Moreover,the relationships between the errors and the beam shaping effect of each shapers are analysed.Subsequently,the relationship between the errors and the optical fiber coupling efficiency is analysed.The result shows that position errors in the Z axis direction on the fast axis collimator have the greatest influence on the shaping effect,followed by the position errors in the Z axis direction on the converging lens,which should be strictly suppressed in actual operation.Besides,the position errors have a significant influence on the optical fiber coupling efficiency and need to be avoided.

Wavelength dependent loss of splice of single-mode fibers

After reviewing three different definitions of mode field diameter of single-mode fibers, coupled efficiency calculation methods associated with lateral offset, longitude separation and wavelength, the effects produced by them, and the influences of splicing defects were discussed in detail. The regularities of the effects were studied according to the first order derivation of couple efficiency formula, and a simplified formula for couple efficiency calculation was presented under the circumstance of slight misalignment, with respect to wavelength, 2, and in a good agreement with the theoretical model. The simplified formula provides a new but simple approach to evaluate wavelength dependent couple efficiency of single-mode fibers. Theoretical analyses and numerical calculations show that, when those defects exist, the wavelength produces additional effects on the couple loss that growth of wavelength causes an increase on the couple efficiency for the lateral offset or longitude separation whereas lessens the couple efficiency due to angular misalignment or mode fields mismatching, and that the wavelength degrades the couple efficiency distinctly when λ≥2.5 μm whereas it distorts the couple slightly in range of λ≤2λ≤2 μm.

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers.We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide.The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm.Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm.Therefore,our invariable coupling power technique is simpler than Intel's.

Design of coupling system in fiber optic sensing measurement

According to the principle of choosing the light source in the fiber optic sensing measurement,semiconductor laser is used as the light source of fiber optic sensor and single-mode fiber is used as the tail fiber of light source. Based on optical design software Zemax’s pure non-sequential components,a coupling system of semiconductor laser and single-mode fiber is designed. By analyzing the beam characteristics of the semiconductor laser and the coupled mode theory of semiconductor laser and single-mode fiber,the combined lens consists of a ball lens and a collimating lens for the purpose of improving the coupling efficiency and adjusting tolerance. The simulation results show that the coupling efficiency can reach about 78% by using one million ray traces on non-sequential components,while the experimental test result is 69.11%,accordingly,the reasons for the difference between the experiment and the simulation results are analyzed.

光纤照明——一种现代化的照明方式(上)

光纤应用于照明已取得了很大的进展。它从最初仅仅用来产生特殊的照明效果(如闪耀的星光),到如今不但广泛应用于装饰性照明,而且可以应用于一般性照明,亦即光纤照明已经进入了真正的全方位的照明领域。特别是那些普通的照明设备无法实现照明的场所,更是光纤照明的时代了。...

Periodical rocking long period gratings in PANDA fibers for high temperature and refractive index sensing

We report periodical rocking long period gratings(PR-LPGs) in PANDA fibers fabricated with CO_2 laser. The PR-LPGs achieve very high coupling efficiency of 19 dB with 12 periods and a 3.5° twist angle in just one scanning cycle, which is much more effective than the conventional CO_2 laser fabrication technique. This type of LPGs exhibits polarization-selective resonance dips which demonstrate different sensitivities to environmental parameters. The high temperature and external refractive index sensitivities are measured simultaneously, so it can be used as a wavelength-selective polarization filter and sensor.

Rational design of perfectly oriented thermally activated delayed fluorescence emitter for efficient red electroluminescence

How to control the dipole orientation of organic emitters is a challenge in the field of organic light-emitting diodes(OLEDs).Herein,a linear thermally activated delayed fluorescence(TADF)molecule,PhNAI-PMSBA,bearing a 1,8-naphthalimide-acridine framework was designed by a doublesite long-axis extension strategy to actively control the dipole orientation.The horizontal ratio of emitting dipole orientation of PhNAI-PMSBA reaches 95%,substantially higher than that of isotropic emitters(67%).This unique feature is associated with the intrinsically horizontal molecular orientation of PhNAI-PMSBA and the good agreement between its transition dipole moment direction and molecular long axis.The PhNAI-PMSBA-based OLED achieves an ultrahigh optical outcoupling efficiency of 43.2%and thus affords one of the highest red electroluminescence with an external quantum efficiency of 22.3%and the Commission International de l’Eclairage 1931 coordinates at around(0.60,0.40).

Suppression of fluctuation on the angle of arrival for freespace optical communication

In order to increase the coupling efficiency and suppress the random angular jitter induced by atmosphere turbulent, the fine tracking system with fast steering mirror （FSM） is demonstrated. The field experiment results of free-space optical communication link across 16 km show that when there is no tracking, the range of the x-axis coordinates＇ fluctuation achieves 46 pixels, corresponding to the incident angle of 73.6 μrad, and its mean square deviation is 6.5 pixels, corre- sponding to the incident angle of 10.4/.trad. When there is tracking, the range of fiuctuation is suppressed to 10 pixels and 16 ktrad, and the mean square deviation reduces to 1.5 pixels and 2.6 brad for the spot＇s centroid and the incident angle, respectively. Significantly, the coupling efficiency increases by 6 times, and the fluctuation of received light power decreases obviously.