Strain-induced thermally tuned long-period fiber gratings fabricated on a periodically corrugated substrate

This paper reports the characteristics of a strain-induced thermally controlled loss-tunable long-period fiber grating (LPFG) fabricated on a prepatterned corrugated substrate. Periodic microbending at the fiber-subtrate interface induces mode coupling between the core find asymmetrical cladding modes that yields narrow-band attenuation as large as -25 dB. Several-parameters that affect the performance of the tunable LPFG, such its the diameter of the etched fiber, number of grating periods, curing condition, and thermal expansion properties of the bonding materials,are investigated. This paper also demonstrates the integration of an on-chip thin-film microheater that also functions as a temperature sensor for the LPFG.