Optical materials in the optical printed circuit board are required to overcome soldering process. In detail, the material
should not have absorption and shape changes after several tens of seconds heating at around 250°C. For such
application field, we have developed a novel organic-inorganic hybrid material having a high thermal stability and low
absorption at telecom wavelength.
The material is designed to UV and/or Thermal curable resin, and soluble to popular organic solvents. We fabricated a
rigid optical waveguides on a SiO2/Si wafers by UV lithography. The size of waveguide was 40 μm in width, 30 μm in
height, and 7 cm in length. Optical attenuation of the waveguide measured by the cut back method was 0.1 dB/cm at 850
nm, 0.29 dB/cm at 1310 nm, and 0.45 dB/cm at 1550 nm. These values are good low attenuation for the Near-IR optical
communication. The 5% weight loss temperature of the UV cured material was 402°C. The waveguide showed almost no
attenuation increase even after 1min heating at 300°C.
In addition, the material is having a high refractive index of n=1.60 at 633 nm and a low curing shrinkage of 4.7%. We
have demonstrated to fabricate a bulk body sample by UV curing, and obtained high uniformity cured materials with 5
mm-thick and 1 cm-diameter.
From these properties, the developed organic-inorganic material is expected to be beneficial for the optical
interconnection such as micro lenses and optical packages.