Fabrication And Characterization Of Planar And Ridge Waveguides In Magneto-Optical Glasses

An optical isolator is one of the most important components in optical system because it allows only one direction of light to pass through and isolates the transmission of reverse direction light.Nowadays,commercial optical isolators are all bulk optical isolators.With the development of integrated optical path,traditional optical isolators are not easy to integrate.Optical waveguide,as the core component of waveguide optical isolation,can confine light to the micron range for transmission,it greatly improving the optical density.The excellent performance of optical waveguides determines the performance of waveguide-type optical isolators.The fabrication of optical waveguides for optical isolators has been a research hot topic for scholars at home and abroad.The magneto-optical glasses of boro-aluminosilicate system are the basic material for magneto-optical devices due to its excellent optical and thermal stability,large verdet constant and high transmittance in the visible and near-infrared regions.Ion implantation is a material modification technology that has been developed for nearly 60 years.Optical waveguides have been successfully fabricated on more than 100 materials.Ion implantation technology can control the species,energy and dose of implanted ions.It possesses the advantages of simplicity,flexibility and high precision.However,ion-implanted magneto-optical glass can only produce planar optical waveguide structures that limit light propagation in one dimension.Ridge waveguides have small cross-sectional area and can restrict the transmission of light in two dimensions,which is more advantageous for integration.The methods of fabricating ridge waveguide include ion beam etching,femtosecond laser etching,precise diamond blade dicing,wet etching,etc.Compared with other technologies,the ridge waveguide fabricated by precise diamond blade dicing technology has smooth side wall and less transmission loss.This paper studies the fabrication and related properties of planar and ridge waveguides on magneto-optical glasses by ion implantation and precision diamond blading technology,which provides a new idea for the application of magneto-optical glass waveguides in optical isolators.The main work is as follows:1.Fabrication of planar optical waveguide by hydrogen ion implantation in the magneto-optical glassThe planar optical waveguide is fabricated by the implantation of single-energy hydrogen ions in the magneto-optical glass.The optical performance of the planar optical waveguide was tested at 633 nm.Four waveguide modes were measured at 633 nm,which is a multimode waveguide structure with a loss of 3.56 dB/cm.2.Fabrication of planar optical waveguide by the dual-energy hydrogen ion implantation in the magneto-optical glassThe planar optical waveguide is fabricated by the hydrogen ion implantation in the magneto-optical glass with energy of 500 keV and 550 keV.Optical properties of the planar optical waveguide were measured at visible(633 nm)and near infrared(1539 nm)wavelengths.With the elongate of wavelength,the transmission mode decreases,the measurement loss is 1.56 dB/cm.Compared with the single energy hydrogen ion implantation,the double energy implantation broadens the optical barrier and reduces the optical propagation loss.3.Fabrication of the planar optical waveguide by the MeV-carbon ion implantation in the magneto-optical glassThe planar optical waveguide is fabricated by carbon ions implantation in the magneto-optical glass with energy of 5.5 MeV and 6.0 MeV.Optical performance of the planar optical waveguide was measured at 633 nm wavelength.There was only one transmission mode at this wavelength,which indicated that the waveguide was a single-mode waveguide with a measurement loss of 1.2 dB/cm.Compared with the multi-mode waveguide structure,the transmission loss of single-mode waveguide is greatly reduced.4.Ridge waveguide fabricated by precise diamond blading on the magneto-optical glassThe planar optical waveguide fromed by single-energy hydrogen ion implantation is diced by Disco DAD3350 precision diamond blade machine to form a ridge waveguide structure.The dicing depth of waveguide is 30 ?m,the ridge width is 8 ?m and the ridge interval is 250 ?m.The mode field measurements of the ridge waveguides at 633 and 106 nm wavelength show that ridge waveguides with a width of 8 ?m can well limit the transmission of light.At 633 nm transmission wavelength,the loss of the ridge waveguide is 3.28 dB/cm.