Low-loss passive polymer waveguides by using chlorofluorinated polyimides

Chlorofluorinated polyimides were prepared from 2,2-bis(3,4-dicarboxyphenyl )hexafluoropropane dianhydride (6FDA), 2,2'-bis(trifluoromethyl)-4,4'-diami nobiphenyl (PFMB), and 2,2'-dichloro-4,4'-diaminobiphenyl (DCB) for optical waveguide applications. The resulting optical polymers exhibited good ther mal stability, controllable refractive index, and low optical loss in the o ptical communication wavelengths of 1.3 and 1.55 mu m The control of refrac tive indices of the polymers was achieved by copolymerization of 6FDA/PFMB and 6FDA/DCB. As the amount of DCB was increased, the refractive indices of polymer were increased. The effect of addition of chlorine on optical prop erties of polymers such as absorption loss in the near-IR region were also investigated. Rib-type optical waveguides were fabricated using these chlor ofluorinated polyimides. These waveguides exhibited low loss of less than 0 .4 dB/cm for both TE and TM polarizations. (C) 1999 John Wiley & Sons, Inc.