솔 - 젤 하이브리드 소재를 이용한 연성 광도파로 제작 Fabrication of Free Standing Flexible Multimode Waveguide

1. Bending Test with Various Cylinder Silylation by HMDS & MFD Under Cladding Coating MD Core UV-Moulding PET Film MFD Over Cladding Coating PET Film Lift Off Final Flexible Waveguide • Role of HMDS : Silylation is the displacement of an active hydrogen( OH on PET) by an organosilyl group Reference 1. W.S. Kim, J.H. Lee, S.Y. Shin, Y.C. Kim and B.S. Bae, IEEE Photonics Technology Letters, 16[8], pp 1888-1890 (2004) 2. W.S. Kim, K.S. Kim, Y.C. Kim and B.S. Bae, Thin Solid Films, in press(2004). 3. W.S. Kim, K.S. Kim, Y.J. Eo, K.B. Yoon, and B.S. Bae, Journal of Materials Chemistry, in press (2004) 4. W.S. Kim, J.K. Kim, Y.C. Kim and B.S. Bae, XX ICG'04 Proceedings, 20, 0-11-039 (2004) 솔-젤 하이브리드 소재를 이용한 연성 광도파로 제작 Fabrication of Free Standing Flexible Multimode Waveguide using Sol-Gel Hybrid Materials (HYBRIMERs) 김 우 수1), 윤 근 병2) , 배 병 수*1) 1)한국과학기술원 신소재공학과 광학재료연구실 ( KAIST ), 2)한국전자통신연구원 광접속모듈팀 ( ETRI ) * E-mail : bsbae@kaist.ac.kr, www.sol-gel.net/lomc Introduction • Flexible waveguide devices have been attracting interest for use in short-distance optical interconnects. • Polymer device is the compatibility with a variety of substrates, such as Si, GaAs, or plastics. • Flexible device can be applicable to board-to-board connection by a polymeric waveguide film with connector. • Escape from the substrate dependence is necessary for optical materials to bend itself b/w shallow board-to-board distance. • In order to ignore the bending excess loss, the refractive index difference b/w core and cladding materials must be high ( >1 % ). • Easy and simple process for the fabrication of flexible optical waveguide is needed for the optical interconnects. • One of the major questions concerning flexible devices is how much they can be bent before their performance is affected. • Flexible Polymer Waveguide • for board-to-board interconnects - I. Basic Investigation: What kind of material & Process are suitable for flexible waveguide? UV Moulding Process HYBRIMER Properties Replicated HYBRIMER Pattern • Easy Viscosity Control • Inorganic-Organic Nano Hybrid Materials • Low Optical Loss mold mold UV- Stamping • “HYBRIMERs” are organic-inorganic hybrid materials, • which can be synthesized using a sol-gel process. • HYBRIMER has advantages afforded by the combined • properties of the organic flexibility of polymers and • the inorganic thermal stability from the inorganic glass • network. • the non-hydrolytic sol-gel process facilitates synthesis • of resin without leaving any trace of solvent. substrate substrate ③ Contact to Substrate ④ UV- Curing ⑤ De-molding & Thermal Curing waveguide patterns mold substrate ② Mold Fabrication ① Master Fabrication Replicated HYBRIMER Pattern mold mold UV- Embossing Less than 1 dB/cm in telecommunication region Viscosity decreased 1/10 by heating without solvent • Thus, crack-free thick-coating films can be easily fabricated without abrupt • shrinkage from non-hydrolytic sol-gel HYBRIMERs • Due to this crack-free pattern structure and minor volume contraction, • HYBRIMER synthesized by a non-hydrolytic sol-gel process is suitable for soft • lithographic moulding processes. substrate substrate • Easy Refractive Index Control • High Thermal Stability ④ UV- Curing ⑤ De-molding & Thermal Curing ③ Coating & Molding • Large Core Waveguide 65 ㎛ 60 ㎛ Representative HYBRIMER :Fluorinated Methacrylic HYBRIMER 62 ㎛ Optically Transparent, Refractive Index Tunable, Good Coating Quality, Low optical Loss • Propagation loss = 0.24 dB/cm @ 850 nm Thermally stable over 300 °C Refractive Index Change: 1.40 ~ 1.65 II. Free Standing Flexible Waveguide with HYBRIMERs Characterization Fabrication • Flexible Waveguide Fabricating Procedure • Bending Test & Measuring Bending Excess Loss Fiber connected waveguide was bended until 2 mm bending radius There’s no bending effect until 1 mm bending radius. • Mechanical Test of HYBRIMER Films • Materials: HYBRIMERs on PET film • Specimen: 1 cm  10 cm • Temperature: 25 °C • Strain Rate: 1  10-3 /sec • Cleaved Edge Image of Flexible Waveguide after Polishing 45 µm 35 µm • UTS (Ultimate Tensile Strength) of MFD : 13 MPa, MD : 10 MPa • cf) glasses (100~120 MPa), thermoplastics ( 5~50 MPa) • Young’s modulus : E= σ/ε, MFD, MD : 0.115 ~ 0.120 GPa • cf) glasses (70~80 GPa), poly ethylene ( 0.3 GPa) •  Mechanically Polymer-like Behavior - Micro-Tensile Test for HYBRIMER Thin Film - Conclusions • Basic Investigations: • Homogeneously synthesized HYBRIMER has good optical properties, good coating quality, and high thermal stability for the flexible devices to apply optical interconnects. • UV moulding process is suitable for the fabrication of easy, cheap and reproducible flexible devices. • Large core ( 50 ~ 100 µm) optical waveguide by HYBRIMER material can be made for optical interconnects with little volume shrinkage. • Free Standing Flexible Waveguide by HYBRIMERs: • Free standing flexible waveguide was made with HYBRIMERs by UV moulding method. • There’s no change of bending excess loss during bending of HYBRIMER flexible waveguide • until 1 mm bending radius. We would like to thank… the Ministry of Commerce, Industry and Energy of Korea, who supported us by Sol-Gel Innovation Project (SOLIP).