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1.5 μm dual-lateral-mode distributed bragg reflector laser for terahertz excitation

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Chinese Optics Letters 2016年第1期14卷 70-74页

作者：张莉萌余力强潘碧玮陆丹潘教青赵玲娟 Key Laboratory of Semiconductor Materials Science Institute of Semiconductors Chinese Academy of Science and Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices

A terahertz excitation source based on a dual-lateral-mode distributed bragg reflector （DBR） laser working in the 1.5 μm range is experimentally demonstrated. By optimizing the width of the ridge waveguide, the fundamental and the first-order lateral modes are obtained from the laser. The mode spacing between the two modes is 9.68 nm, corresponding to a beat signal of 1.21 THz. By tuning the bias currents of the phase and DBR sections, the wavelengths of the two modes can be tuned by 2 nm, with a small strength difference （〈5 dB） and a large side-mode suppression ratio （SMSR 〉 45 dB）.

关键词： bragg reflectors distributed bragg reflectors Laser excitation Reflection Ridge waveguides

distributed bragg reflector laser(1.8 μm) with 10 nm wavelength tuning range

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Chinese Optics Letters 2015年第4期13卷 37-40页

作者：米俊萍于红艳袁丽君李士颜李梦珂梁松阚强潘教青 Key Laboratory of Semiconductor Materials Science Institute of SemiconductorsChinese Academy of Sciences

We report a 1.8 μm two-section distributed bragg reflector laser using butt-jointed InGaAsP bulk material as the waveguide core layer. The threshold current is 17 mA and the output power is 8 mW on average. The threshold current, output power, and emitting wavelength dependences on temperature are measured. The obtained wave- length tuning range is 10 nm. This device has potential applications in simultaneous multiple-gas detection.

关键词： bragg reflectors distributed bragg reflectors Fiber optic sensors Reflection

GaInN light-emitting diodes with omni-directional reflector using nanoporous SnO_2 film

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Chinese Optics Letters 2008年第2期6卷 152-153页

作者：沈常宇冯华君徐之海金尚忠 State Key Laboratory of Modern Optical Instrumentation Zhejiang University Optoelectronics Technology Institute China JiLiang University

Enhancement of light extraction in a GaInN light-emitting diode （LED） employing an omni-directional reflector （ODR） consisting of GaN, SnO2 nanorod and an Ag layer was presented. The ODR comprises a transparent, quarterwave layer of SnO2 nanorod claded by silver and serves as an ohmic contact to p-type GaN. Transparent SnO2 sols were obtained by sol-gel method from SnCl2·2H2O, and SnO2 thin films were prepared by dip-coating technique. The average size of the spherical SnO2 particles obtained is 200 nm. The refractive index of the nanorod SnO2 film layer is 2.01. The GaInN LEDs with GaN/SnO2/Ag ODR show a lower forward voltage. This was attributed to the enhanced reflectivity of the ODR that employs the nanorod SnO2 film layer. Experimental results show that ODR-LEDs have lower optical losses and higher extraction efficiency as compared to conventional LEDs with Ni/Au contacts and conventional LEDs employing a distributed bragg reflector （DBR）.

关键词： Coating techniques distributed bragg reflectors Light reflection Nanorods Ohmic contacts Optical losses Porous materials Refractive index Semiconducting gallium compounds Sol gel process Thin films Tin oxides

Self-imaging effect in photonic crystal multimode waveguides exhibiting no band gaps

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Chinese Optics Letters 2007年第12期5卷 690-692页

作者：于天宝江晓清廖清华戚伟杨建义王明华 Department of Information Science and Electronic Engineering Zhejiang UniversityHangzhou 310027 Department of PhysicsNanchang UniversityNanchang 330047 Department of Information Science and Electronic Engineering Zhejiang UniversityHangzhou 310027 Department of Physics Nanchang UniversityNanchang 330047

The properties of the propagating field in multimode photonic crystal waveguides （PCWs） exhibiting no photonic band gaps （PBGs） are investigated. The transmission spectrum shows that the input field can be guided with high efficiency, and resemble index-guided modes owing to the combination of total internal reflection （TIR） and distributed bragg reflection （DBR）. Self-imaging effect happens and the filling fraction determines the beating lengths. The rows of air holes decide DBR coming from the mirrors on both sides of the guiding region, which governs the transmission spectrum. It provides a new way to realize the components for both polarizations by combining PBG and TIR effects in PCWs.

关键词： distributed bragg reflectors Imaging techniques Light transmission Photonic band gap Photonic crystals

Intracavity frequency-doubled green vertical external cavity surface emitting laser

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Chinese Optics Letters 2008年第4期6卷 271-273页

作者：宋晏蓉张鹏张新平颜博霞周翊毕勇张志刚 College of Applied Sciences Beijing University of Technology Beijing 100022 Academy of Opto-Electronics Chinese Academy of Sciences Beijing 100080 College of Electronic Engineering and Computer Science Peking University Beijing 100871

An intracavity frequency-doubled vertical external cavity surface emitting laser （VECSEL） with green light is demonstrated. The fundamental frequency laser cavity consists of a distributed bragg reflector （DBR） of the gain chip and an external mirror. A 12-mW frequency-doubled output has been reached at 540 nm with a nonlinear crystal LBO when the fundamental frequency output is 44 mW at 1080 nm. The frequency doubling efficiency is about 30%.

关键词： distributed bragg reflectors Mirrors