| With the development of integrated devices in radio frequency(RF), microwave, terahertz wave and optical band, an idea has been brought forward, that is how can we investigate a kind of film using in microwave, terahertz (THz) and optical devices and realize the integrated devices in range from microwave to optical band. The main work of this thesis is the verification of the imagination. Firstly, three kinds of garnet films were designed based on its low propagating loss in microwave devices and magneto-optical devices and potential application in terahertz band; Secondly, several kinds of garnet films were realized by liquid phase epitaxy (LPE) method with lead-free flux and RF magnetron sputtering, and their properties and application in microwave, terahertz and optical band were analyzed in detail; Finally, the application of garnet films using in these devices were investigated, the test results show that these garnet films have good performance in three wave band and it is very important to future integrated devices.Based on the abovementioned ideas, many investigations have been done on basic theories, material preparing technologies and devices designing. In this thesis, the main work is just as follows,(1) The investigation of LuBiIG mono-crystal garnet film by buffer LPE method with lead free flux has been done. The microstructure, surface condition and deficiency controlling technologies of large area film were studied in detail. The buffer LPE method which is suitable for lead free flux technology has been brought forward, and the point is the effect of axis of GGG substrate and film growth rate to the films qualities. At last, the film combined with both superior magnetic and magnetic-optical properties together is obtained by optimizing LPE technology, and the lattice of the thin film has a good match with the GGG (111) substrate and good surface. The saturation magnetization (Ms) of the film is about 1562Gs, the Faraday rotation is 1.6～2.0deg/μm and the minimum FMR linewidth value is 2△H=5.1Oe.(2) The application of microwave sintering (MS) technology in ferrite garnet materials has been carried out. The MS method has been applied in garnet target sintering and the garnet target with good performance is obtained by optimizing sintering curve and temperature. Experiments show that microwave sintering (MS) treated YIG materials possess excellent properties in target density, dielectric loss, dielectric constant and magnetic loss besides high efficiency and saving time. If the room with even temperature in MS oven is enlarged, the MS method is not only making for improving performance of garnet substrate using in microwave devices, but also voluble for preparing sputtering targets.(3) The investigation of garnet films by RF magnetron sputtering has been done in this thesis. The effects of substrate, sputtering parameters, post-treated technology to the film performance have been studied in detail. The films with dense structure, smooth surface condition and adjustable saturation magnetization have be prepared by optimized technology. Additionally, the monocrystal garnet film can be obtained on GGG substrate by controlling the sputtering and annealing technology.(4) The investigation of rapid recurrent thermal annealing (RRTA) theories and technology has been done. The RRTA nanometer crystallizing quantum kinetics model was created and the rules of crystal core forming and growth in the process of crystallizing were analyzed. The results show that the crystal grains scale of garnet films can be decreased efficiently by RRTA method, which leading to the increasing of magneto-optical effect and the Faraday Angle is doubled.(5) The investigation of theories and experiments of magnetostatic surface wave (MSSW) filter has been done in chapter 4. Firstly, the insertion loss model of MSSW filter has been created, and the effect of the thickness of garnet film, saturation magnetization and linewidth to the insertion loss of the filter have been analyzed in detail; Secondly, the dispersion restrain theory with the double magnetic layer structure has been created; Finally, the filters with good performance were realized with LuBiIG film. The filter parameters are as follows, the center frequency is between 4.0 and 5.5GHz, the pass bandwidth is 180±10MHz, insertion loss is smaller than 8.0dB (this value can be reduced to 6.0dB with double magnetic layer structure), and out-band rejection is bigger than 35dB.(6) The feasibility investigation of microwave ferrite film circulator has been done. Based on circulator design theory, the effect of thickness of substrate or film to the circulator performance has been investigated. The results show that the film circulator can be realized from 1.0GHz to 3.0GHz by perfecting garnet film preparing technology, however, it is still needs a long time to be realized because of its restriction conditions in high frequency band.(7) The investigation of THz response of garnet film has also been done. The transmittance performance of LuBiIG garnet film by LPE method and polycrystalline garnet film by RF magnetron sputtering in THz frequency range has been investigated and the results show that garget film is with low absorbance coefficient at THz band, and minimum value is 0.01- 0.2/cm, and garnet films are potential materials in THz wave-guide application.(8) At last, the investigation of garnet film plane wave-guide switch has been done. Based on the giant magneto-optical (MO) Faraday Effect of Bi :YIG garnet, the model of wave-guide MO switch has been created and the factors which affecting the performance of the switch have been analyzed by applying MO transmittance theory, and the wave-guide MO switch has been realized at last. Its insertion loss is between 0.6 and 3.0dB, on-off rate is between 40μs and 2ms.
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