We have demonstrated controlled erasure of localized FBGs using post-inscription femtosecond treatment. The Bragg wavelength can be tuned via applied strain, as well as through pre- and post-femtosecond processing. Additionally, we achieved wavelength tuning by introducing defocusing lenses into the inscription beam path.
Grating arrays with multiple Bragg wavelengths have been inscribed at the same spatial location. We also observed transient FBGs in reflection and transient phase-shifted FBGs in transmission.
Our system enables inscription in various fiber types, including passive, active, and large-core fibers, which are subsequently integrated into our in-house fiber laser systems. Beyond laser cavity applications, these FBGs are also investigated for sensing applications.
The laboratory is further equipped with 266 nm femtosecond pulses (via third-harmonic generation) and near-IR to mid-IR femtosecond pulses generated by an optical parametric amplifier (OPA).
This research is ongoing.