Study On The Material Of VECSEL Gain Chip Based On InGaAs Quantum Well

Vertical external cavity surface emitting laser (VECSEL) is a new type of optoelectronic device developed in recent years. It successfully combines the advantages of the expansion of the external cavity and the adjustability of the wavelength of the semiconductor laser, It can not only obtain high output power and high beam quality, but also can be used for intracavity frequency doubling and Q modulation, locking operation and so on, As one of the hot topics in the research of semiconductor laser and optoelectronic technology. Therefore, in this thesis, we have studied the material of VECSEL gain chip based on InGaAs quantum well, and on the basis of this, the fabrication of optical pumped VECSEL has been carried out.First of all, based on the theory of reflectivity and bandwidth of the distributed Prague reflector (DBR), the strain theory and gain theory of gain material, the theoretical calculation and structure design of DBR and multi quantum well active region (MQWs) are carried out, and on the basis of this, the whole structure of VECSEL gain chip is designed. Secondly, the material is prepared by metal organic vapor phase epitaxy (MOVPE),and uses high resolution X-ray diffraction (XRD),room temperature photoluminescence (PL), scanning electron microscopy (SEM), and spectrophotometer are used to verify the design of the gain chip. The DBR test results show that the thickness error is able to achieve about 3%, and the stopband is about 100 nm at the center of 997 nm.The emitting wavelength of multi quantum well active region can be adjusted by control the linear TMIn flow in the range of 961 nm-1000.6 nm. The results show that the crystal quality of the epitaxial material is good, the thickness of the epitaxial material is satisfied, and the reflection spectrum of the DBR and the luminescence spectrum of the quantum well can match well. In addition, it is analyzed that VECSEL gain chip is a the surface-emitted photoluminescence spectrum that are strongly modulated by interference with in the multilayer,while the PL spectra of active region is an intrinsic spectral profiles, free from modulation by interference effects, that is a representative set of edge-emitted photoluminescence spectra. The observed PL is a function of the QW emission and the spectral filtering causedby the micro-cavity resonances.Finally, we design and build the optical pumping VECSEL. The method of substrate etching and water cooling is adopted to remove the waste heat generated in the process of gain chip.A 808 nm semiconductor laser as the optical pumping source of light. When the incident light power is less than 3W, the pump absorption rate of the VECSEL gain chip is up to about 80%.The light pumped VECSEL device gets a strong light output at the 955.3 nm.and 1011 nm in the positive sequence VECSEL device,and at 1113 nm in the reverse sequence VECSEL devices.