Fluorine‐containing optical adhesives for optical communications systems

Fluroinated epoxy resin adhesives containing diglycidylether of bisphenol AF (DGEBAF) with a fluorine content of 25.7 wt % are developed for fabrication of optical communications devices. These adhesives, formulated with a diluent of butanediol diglycidylether (BDDG) and a curing agent of polyether polyamine (Q694), can be cured at a curing temperature as low as 65°C and exhibit high transparency of more than 80% in the wavelength range of 0.5–1.3 μm. Moreover, they significantly reduce return loss at optical‐glass/adhesive interfaces because of the low refractive indices of ca. 1.52 and also improve heat durability of optical devices. They are successfully applied to submarine optical fiber transmission system.