| Vertical cavity surface emitting laser(VCSEL)as compared to edgeemitter has a small divergence angle,circular spot which can be easily coupled with an optical fiber,single longitudinal mode operation,is easy to integrate the two-dimensional array,a wafer-level testing,low cost and other advantages,has gradually replace other devices in many areas.In particular high-power vertical-cavity surface-emitting laser pumping efficiency due to its high fiber and an ideal pump light source,has become an ideal light source for optical interconnection,optical communications,optical computing and other fields.How to further improve the output power of the semiconductor laser has been the primary goal of research scholars.At present the problem of high power vertical cavity surface emitting lasers is how to obtain high power,at the same time,have high reliability and high energy conversion efficiency,high beam quality and good spectral characteristics.Due to the skin effect and carrier aggregation effect of current,the working current injected into the active region only passes through a narrow channel in the edge ring region,and the laser power density distribution is uneven,resulting in the ring-shaped laser spot.This phenomenon will have a great impact on the output quality of large aperture devices.Therefore,a new type of VCSEL with a novel optical hole structure is proposed.This design can make the light-emitting region adapt to the carrier aggregation effect,make full use of the central region of the traditional structure which is almost no light-emitting,increase the effective light-emitting area of the device while maintaining high power output.It not only meets the demand of VCSEL for high power semiconductor laser source in the field of optical communication,but also improves the beam quality,makes it easier and more effective to collect the imaging system or focus into the diffraction limit spot,and further expands the application of VCSEL in the field of intelligent equipment.The main work of this paper is as follows:1.Based on the data of 808 nm VCSEL structure,the basic model is designed and simulated by pics3 d software.The distribution of refractive index,normalized standing wave electric field intensity in resonance cavity and the gain curve of VCSEL at room temperature are obtained,and the phenomenon of uneven optical field distribution of traditional large aperture VCSEL is verified.2.A new type of optical hole structure and electrode arrangement is designed for 808 nm VCSEL,and the optical field of large aperture VCSEL with different electrode width and arrangement is simulated and analyzed by FDTD software.3.According to the simulation results,a mask with different width ratio is designed.And the key technologies of VCSEL preparation were studied,including UV lithography,wet oxidation and dry etching.The temperature dependence of wet oxidation process is studied in detail,and the relationship curve between oxidation rate,oxidation temperature and oxidation time is obtained.The relationship between oxidation hole figure and oxidation temperature is explored,and the temperature control curve of oxidation furnace is optimized.At room temperature,when the input current is 0.8A,the output power reaches 140 m W,and the maximum output power reaches 0.387 w under the far-field test condition. |
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