| Since the concept of integrated optics has been put forward,it has been widely concerned.It adopts an integrated method to study related aspects of optics and optoelectronics,involving wave optics,nonlinear optics,information optics,crystal optics,thin film optics,semiconductor optics,related device design,system integration theory and application etc,by integrating different optical devices according to the requirements of a certain number,order,position and other related aspects,the preset specific aspects or multiple aspects of optical functions can be realized.In optical information processing,optical fiber communication networks,fiber optic sensors,optical storage,optical precision measurement,optical instruments and spectroscopy applications are widely used.The optical waveguide is a structure formed by a medium with a slightly higher refractive index and a thickness that is similar to the wavelength of the light by being wrapped in a medium with a lower refractive index.It can limit and guide the transmission of light under different spatial dimensions and structure.The light transmitted in the optical waveguide is generally limited to tiny areas of the order of micrometers.Due to the obvious size reduction compared to the bulk material,this will increase the light intensity in the optical waveguide area to be much larger than the bulk material.The high value that can be reached in the optical waveguide,so it has a higher research value and a wider range of applications.Passive optical devices,such as optical switches,and active optical devices,such as optical modulators,optical amplifiers,and lasers,can be fabricated based on the optical waveguide structure.Compared with traditional passive optical devices,the light guide structure can better limit the light.Cross-section of size microns or even smaller makes the energy density inside the optical waveguide higher,achieving higher energy conversion efficiency and lower laser thresholds.This makes the optical waveguide an important part of integrated optics and the most basic optical element,and at the same time it is a carrier for connecting photonic devices with different functions in the integrated photonics system.Energetic Ion Beams technology is a method of fabricating an optical waveguide structure by interacting with optical materials to change the refractive index of the material in the irradiated area.According to the different technical methods,energetic ion beams technology can be divided into ion implantation,swift heavy-ion irradiation and focused ion beam writing.By setting different energies,doses,ion species and ion beam sizes,a variety of optical waveguide structures on the order of micrometers and submicrometers can be fabricated on different optical crystals.By effectively modulating the refractive index or surface structure of a material,various applications can be realized in many branches of photonics.At present,optical waveguide structures have been fabricated in more than one hundred materials.Combined with auxiliary methods such as photolithography or femtosecond laser direct writing technology,optical waveguide structures with more complicated structures and superior performance can also be fabricated.Moreover,the optical waveguide structures and other optical structures fabricated by the energetic ion beams technology have shown good wave-guiding performance and characteristics related to the substrate material,which indicates that it has wide application potential in many aspects of photonics.Faraday magneto-optic effect is a kind of bias ingesting in the direction of light vibration produced by magnetic field acting on the light field according to the nature of the material.That is,when a beam of polarized light is under the influence of a magnetic field parallel to its transmission direction,its light vibration direction changes with the magnetic field,and the angle of deflection is proportional to the product of magnetic induction intensity and the distance of light transmission in the medium.The proportional coefficient,which is the Verdet constant,is a parameter that is related to the nature of the medium and to the frequency of the transmitted light.The nature of the transmitted optical medium and the direction of the applied magnetic field together determine the direction of vibration deflection of the transmitted light.This effect can be used for the analysis of substances,such as hydrocarbons,because different hydrocarbons have their own different Faraday magneto-optical rotation properties Spectroscopic analysis can also be used to obtain the excitation-level related knowledge content.Laser technology applications can be used to isolate reflected light to achieve the role of modulation light.In this paper,the main application of ion irradiation/injection technology to Terbium gallium garnet(Tb3Ga5O12,TGG)microstructure modification,and the fabrication of optical waveguide structure,and carried out a series of experiments to test and study the properties of optical waveguide,including optical waveguide microscope photos,dark model,fitting refractive index distribution,waveguide mode,propagation loss changes,Raman spectra and other wave-guided optical properties,and the addition of external magnetic field based on this,studying magneto-optical rotation characteristics,to achieve the magneto-optical rotation effect of light inside the optical waveguide,analyzing the practical application of optical waveguide.According to the different methods of optical waveguide fabrication,the research work and results of this paper are discussed as follows:Ion irradiated optical planar waveguides based on TGG crystal:The main work is to fabricate a magneto-optical waveguide based on TGG crystal by irradiation with 15MeV C3+ ion beam.The energetic ion beam irradiation process causes the optical anisotropy in the irradiated TGG crystal optical waveguide,which hinders the magneto-optical rotation in the optical waveguide.In order to eliminate the optical anisotropy caused by irradiation of energetic ion beams,we anneal the irradiated TGG crystal optical waveguide under different conditions.After annealing for one hour at 400?,under the action of an external magnetic field of 0.24 T,the incident light with a wavelength of 632.8 nm was observed to rotate at 14° per centimeter in the optical waveguide.The results observed in the crystals are comparable.This work paves the way for the application of TGG crystal optical waveguides as integrated optical rotators and isolators. |
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