Research On Coupling VCSEL Array Beam Steering

Vertical-cavity surface-emitting lasers(Vertical-cavity surface-emitting lasers, VCSEL) coupled array with high brightness, near diffraction- limited high quality beams, single mode mase, phase-locking and other feature advantages, so it could has been ful y applied in laser radar, beam controllable light sources, spectrum sensing, optical logic processing and other fields. In this paper, we study the beam steering of coupled VCSEL array, which is by changing the current-injection to control unit of beam deflection, then to get the high-speed high-precision scanning of a laser beam. At first, we have reported the research status of coupled VCSEL arrays and beam steering, studied the principle of beam steering, according to the study based to experimenta l designed, and then simulated the experimental scheme based on the principle of beam steering, improved the technological process, and at last have produced the devices with high degree of coupling and high steering-angle, and design to get the complete testprogramme. Main summary as follows:1. Experimental design and simulationBefore the beam steering, first is to obtain high beam quality. According to the existing research results of our research group about coupled VCSEL arrays, have determined the two array sizes for 1×2 and 1×3, respectively. This is the experimenta l scheme. For better study of beam steering mechanism, we simulate electric and thermal field distribution of mutual coupling in devices at first by software COMSOL Multiphysics, and then simulate the effect of refractive index, initial phase difference, different unit sizes and spacing's to coupling beam deflection in far-field by software FDTD Solutions.2. The preparation processBy design scheme of devices and the laboratory technology conditions, the preparation process and layout are designed, and through the actual encountered problems in the experimental preparation procedure to further optimization. By introducing nano-metal layer as current spreading layer, improved the reliability, while ensuring the current of each unit were respectively be injected. Finalize a set complete preparation technology of coupled VCSEL array beam steering devices.3. Test data analysisThe systematic and detailed testing for near-field, far-field, optical power and spectra of the sample devices have been made. The near-field measurement data of 1×2 arrays have been compared, find the influential law of element spacing to coupling current; in the near-field testing of 1×3 arrays, revealed coupling current below the threshold current and three-element coupling lower than two units coupled into the injection current, and explained about this. By compare the optical power and spectra with near-field and far-field data under the same injection current conditions, the optical power and spectra all were influenced by the coupling efficiency in the beam steering process. According to the test and analysis, got a perfect testing scenarios of coupled VCSEL array beam steering.