Study Of Traveling-wave Electrode Of Polymer Electro-optic Modulator

In this dissertation, studies of traveling-wave electrode of polymerElectro-optic modulator, including theoretic analysis, optimizing, design,fabrication and testing, were carried out. The main results include:(1) Five types of electrodes were presented and compared to each other byFEM. The polymer electro-optic modulator with MSL electrode, whichbandwidth is 39.9 GHz and half-wave voltage is 2.275V at wavelength 1.319μmand length of interactive region 20mm, were designed.(2) MSL traveling-wave electrodes of polymer Electro-optic modulator weredesigned. The method of transition from MSL to CPW has solved theconnection between MSL and coaxial connector. Dimensions and performanceparameters of transitional region were computed in detail. For MSL,bidirectional mask and ramose mask were designed respectively. Both maskshave improved the chances of successful fabrication of MSL modulator.(3) Two types of 15 CPW electrodes based on silicon, quartz and glasssubstrates were fabricated, 10 electrodes among which were based on thepolymer layers. All of them were tested for S parameters.(4) According with the theoretic results, tested Nm is 1.689, α0 is0.32dB /(cm GHz) of 20GHz CPW electrodes based on the quartz withpolymer layers, while tested α0 is 0.35dB /(cm GHz) of 40GHz CPWelectrodes.(5) The bandwidth of polymer Electro-optic modulator, which is computedusing tested parameters, is more than 37GHz, exceeding the target 20GHz. Itwas proved that this kind of electrode is fit for the polymer modulator.(6) Tested results have showed that the loss of CPW based on the silicon ismuch more than that on the quartz or glass, for the low resistivity of silicon.The solution would be to use substrate quartz rather than silicon. - II -(7) The total fabricating process has been created and developed. Thedissolution between polymer layers has been solved. The fabricating period hasbeen reduced to several hours from about a week. It has been solved thatphotoresist would fall off the golden electrode during the electroplating process.The problem that cladding layer NOA73 would crack during the sputteringprocess has been also analyzed. BPAN/M20S has replaced NOA73 as claddingmaterial.