Kwansoo Han

Synthesis of fluorinated polyimides and their application to passive optical waveguides

Fluorinated and chlorofluorinated polyimides with high thermal stability and low optical absorption loss in the optical communication wavelengths of 1.3 and 1.55 μm were investigated for low-loss passive waveguide applications. These polyimides were prepared from pyromellitic dianhydride (PMDA) with 1,4-bis-[4-amino-2-(trifluoromethyl)phenoxy]tetrafluorobenzene (ATPT), 1,4-bis-[4-amino-2-(trifluoromethyl)phenoxy]benzene (ATPB), and 1,3-bis-[4-amino-2-(trifluoromethyl)phenoxy]-4,6-dichlorobenzene (ATPD). Control of the refractive indices of the polymers was achieved from 1.5397–1.5671 for TE polarization and 1.5239–1.5513 for TM polarization at 1.55 μm by copolymerization of PMDA/ATPT and PMDA/ATPB. As the amount of PMDA/ATPT was increased, the refractive indices of the polymers were decreased. Rib-type optical waveguides were fabricated using these fluorinated polyimides. These waveguides exhibited a low propagation loss of less than 0.5 dB/cm at 1.55 μm.

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′-diaminobiphenyl (PFMB), and 2,2′-dichloro-4,4′-diaminobiphenyl (DCB) for optical waveguide applications. The resulting optical polymers exhibited good thermal stability, controllable refractive index, and low optical loss in the optical communication wavelengths of 1.3 and 1.55 µm. The control of refractive 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 properties of polymers such as absorption loss in the near-IR region were also investigated. Rib-type optical waveguides were fabricated using these chlorofluorinated polyimides. These waveguides exhibited low loss of less than 0.4 dB/cm for both TE and TM polarizations.

Synthesis and properties of chlorinated polyimides

Full paper: A series of diamines with various chlorine content was synthesized. Using these novel diamines, a series of new chlorinated polyimides was prepared by reacting them with 2,2-bis(3,4-dicarboxyphenyl)hexa-fluropropane dianhydride (6FDA). The purpose was no investigate the effect of the chlorine content on the proerties of polyimides, such as thermal and optical properties. The in-plane refractive (n te ) indices of polymer films increase with increasing order of in-plane orientation in these polyimides. The out-of-plane refractive (n tm ) indices increase with chlorine content.

Chloro-Fluorinated Polyimides for Low Loss Optical Waveguides Application.

Optical polymers which exhibit good thermal stability, controllable refractive index, and low optical loss in the optical communications wavelength of 1.55 µm were prepared using fluorinated and chloro-fluorinated polyimides. As the chlorine moiety is increased, the refractive indices of polymer are increased from 1.5176 to 1.5714 for TE polarization and from 1.5076 to 1.5590 for TM polarization at 1.55 µm. Single mode rib type polymer optical waveguides were fabricated using fluorinated and chloro-fluorinated polyimides. These waveguides exhibit a low propagation loss of less than 0.4 dB/cm at 1.55 µm, and a very low polarization dependent loss of less than 0.01 dB/cm.

Evaluation of halogenated polyimide etching for optical waveguide fabrication by using inductively coupled plasma

Oxygen plasma etching of a series of halogenated polyimides was carried out for low-loss waveguide fabrication by using inductively coupled plasma (ICP). The effects of etching parameters such as ICP power, rf power, and O2 flow rate on the etching rate and etching profile of polymer films were investigated. The increase in the etch rate with the ICP power and the rf power was observed. Both the vertical profile and sidewall roughness were found to be related to the ion energy (dc bias). By optimizing these parameters, a vertical profile and a smooth sidewall were obtained by 500 W of ICP power, 150 W of rf power, 5 mTorr of chamber pressure, and 40 sccm of the O2 flow rate.

Chloro-Fluorinated Poly(arylene ethers) for Optical Waveguide Application

Abstract Optical polymers which exhibit good thermal stability, refractive index controllability, and low optical loss in the optical communication wavelengths were developed by using chloro-fluorinated poly(arylene ethers).

Polymeric Optical Waveguides using Fluorinated Polyimides

Abstract Fluorinated polyimides with high thermal stability and low optical absorption loss have been investigated for waveguide application. Rib-type optical waveguides were fabricated using these fluorinated polyimides.