There has been a rapidly increasing demand for the high numerical aperture (NA) in specialty optical fibers used in
recent high power fiber lasers and remote sensing applications. Various polymer clad resins (PCR) have been reported
aimed for a low refractive index to achieve a high NA, which resulted in a lower modulus. In this study, we report a
novel PCR with a higher modulus whilst maintaining a high NA over 0.44 using newly designed fluorinated oligomer
and monomer having low refractive index and high functionality. Some resins prepared various formulations using
synthesized oligomers and then compared curing speed.
In order to clarify the relationship between the water resistance and compositional additives in the primary coating for optical fibers, we prepared various primary coatings that contained silane coupling agents in combination with amine synergists. We observed the appearance of the interface between glass and primary coating after soaking in water at 65° for 30 days. Water resistance was found to be heavily influenced by the content and type of silane coupling agents and amine synergists and their trends are reported.