Research On Molding Technology Of Polymer Optical Waveguide For Electro-Optical Printed Circuit Board

With the rapid development of information technology,the data transmission within printed circuit boards has been escalated exponentially.Due to the inherent physical defects of copper wires,the parasitic effects of printed circuit boards under high frequency conditions are getting more serious.In order to adapt to the increasing trend of broadband transmission,the use of optical interconnection instead of electrical one is an applicable solution.The polymer-based optical waveguide manufacturing process can be modified to become compatible with the traditional printed circuit board manufacturing process,the optical waveguide can be combined with the traditional printed circuit board to form an electro-optical printed circuit board through lamination.Based on the background of optoelectronic interconnection technology and the main structure of electro-optical printed circuit board,this thesis studies the fabrication of optical waveguides in both theoretical and experimental aspects.Among the many preparation methods,the soft lithography method is simple in process and can provide higher preparation accuracy.However,the roughness of the sidewall of the optical waveguide manufactured by this method is relatively large.The increase of surface roughness will increase the light scattering loss,which greatly affects the performance of optical devices.This work proposes a method for reducing the roughness of the sidewall by thermal reflow,which improves the performance of the optical waveguide.In this paper,the polymer-based optical waveguide is simulated based on the electromagnetic theory,The finite-difference-time-domain(FDTD)method is used to simulate the optical waveguide device,and the influence of the surface roughness of the optical waveguide on the optical signal transmission effect is obtained.The simulation results show that the larger the surface roughness of the device,the weaker the optical signal received by the monitor,and the greater the signal transmission loss.This paper explores the preparation conditions of optical waveguide on electrooptical printed circuit board,mainly including the manufacturing of the elastic Polydimethyl-siloxane(PDMS)mold and the manufacturing of the polymer-based optical waveguide.The traditional process is improved through experimental exploration,and the optical waveguide after the molding is thermally reflowed to improve the side wall roughness,the sidewall roughness is reduced from 0.16 ?m to 0.11 ?m.In the experiment,a complete optical waveguide sample was finally manufactured.The optical waveguide samples were tested for light transmission,optical loss test,crosstalk test and process reliability test.In the case of a wavelength of 850 nm,the transmission loss of the optical waveguide was reduced from 0.70 d B/cm to 0.52 d B/cm.The loss situation has been significantly improved.After heating and cooling cycle treatment and reflow soldering treatment,the performance of the optical waveguide has almost unchanged,indicating that it can be compatible with the temperature difference environment in the manufacturing process of the printed circuit board.At the same time,the optical waveguide fabricated by this method has good repeatability and stability.In summary,the paper concludes that the improved optical waveguide process has important practical significance for the performance improvement of high-performance information transmission systems and industrial production.