Optical circuits in fiber cladding: Femtosecond laser-written Bragg Grating Waveguides

High strength, first order Bragg Grating Waveguides are inscribed in the core and cladding of optical fibers using oil immersion femtosecond direct laser-writing. A laser-induced birefringence of 2.05 × 10
^-4
was inferred from polarization split Bragg resonances.