Second-harmonic generation of second-order modes in thermally poled double-anode optical fibers

Abstract

Second-harmonic generation (SHG) in double-anode thermally poled fibers is numerically investigated. The poling process is investigated based on a two-dimensional charge dynamics model. We show that SHG efficiencies of HE11, TM01, and HE21 modes are affected by χ(2) distribution in the fiber core, which can be deliberately designed by varying poling parameters. Efficient generation of the TM01 mode at second-harmonic (SH) could be achieved in symmetrically double-anode poled fiber, which provides an alternative method to obtain radial vector beams in compact all-fiber-based devices. SHG of HE11 and TM01 (or HE21) modes could also be available at different wavelengths in a single asymmetrical double-anode poled fiber, which can be potentially applied in two-wavelength or ultrabroadband SHG.