Research Of Ion-exchanged Optical Waveguide And Optical Power Splitter

With the developing of PLC and cutting down of cost, it is possible that integratedoptical devices based on PLC replace traditional discrete ones. Ion exchange has becomethe research focus for its main advantages of similar refractive index profile with fiber, littletransmission loss, simple manufacturing technology and low cost over other PLC technolo-gies, especially for applied in optical power splitter in FTTH.This dissertation mainly researches on performance of ion-exchanged optical waveg-uide and design of MMI optical power splitter, which mostly includes solution of indexprofile of grade-index optical waveguide, diffusion theory and technique of ion-exchangedoptical waveguide, mixed salt ion exchange, design of MMI splitter based on ion-exchangedwaveguide. It has been carried out as the followings:Three improved methods of TE/TM, measuring wavelength and external refractive in-dex are addressed and discussed, both of which can satisfy the limitation that IWKB methodis useless when mode number is less than 3. Computing results are implemented from usualfunction refractive index and experiment data. It also showed that these methods couldimprove fitting accuracy when mode number is more than 3.Basic principle of ion exchange and diffusion theory are introduced. Ion exchangeNeural Network based on Particle Swarm Optimization algorithm was proposed to predictcharacters of ion-exchanged waveguide at any arbitrary experiment condition more easilyand quickly, because it overcame the limitation of the conventional theories in which theconclusion had error caused by uncertain diffusion coefficient. This model has the advan-tages of reliability, accuracy, and time saving, which are identified by simulation.Ion exchange of Ag + /K + mixed salts is considered for absorbing the advantages ofAg + (big index change) and K + (small transport loss), avoiding the disadvantages of Ag +(big loss) and K + (slow exchange speed), and dropping exchange temperature.The results of experiments, which are focused on uniformity, birefringence, characterof K+ and K+-Ag+ mixed salt ion exchange, ion exchange time, index profile and differentsubtract glass are discussed and analyzed by the measures of ingredient and refractive indexchange.Principle of multimode is introduced summarily and analyzed by mode transportmethod and beam propagating method. Optimizing design based on GA is brought forward,design result of which shows ability of affording efficient optimized solution.Basic components of waveguide splitter and design ?ow are analyzed in detail.Parameters optimization and technics errors of 1×8 optical splitter at 0.85μm and 1×16 optical splitter at 1.55μm are researched. Cascaded structure of multimode interference isput forward, which shows several advantages to parameters of optical splitter, such as insertloss, uniformity, size, et al.