Improvement on asymmetry of low-loss waveguides written in pure silica glass by femtosecond laser pulses

Abstract

Low-loss and symmetrical mode-field optical waveguides were directly written in a pure silica glass by nearinfrared femtosecond laser processing. By optimizing laser processing parameters, such as the pulse duration and the pulse energy of femtosecond laser pulses, we demonstrated the propagation-loss reduction and the mode- field diameter (MFD) aspect ratio improvement. We have achieved the propagation-loss of 0.10 dB/cm and the MFD aspect ratio of 1.0 at the wavelength of 1550 nm at the same time.