  Quill effect, one of the intriguing phenomena in ultrafast laser writing, to
our knowledge, has not been studied in low-loss-waveguide (LLW) writing regime
yet, probably due to its invisibility under conventional white-light microscope
in that regime. In this report, with help of adaptive third harmonic generation
microscopy we reveal the quill effect in LLW writing regime and study its
influences on the properties of written photonic integrated components in term
of polarization-related properties in fused silica and beam-splitting ratio of
three-waveguide-coupler in borosilicate glass.
