A waveguide includes a core part, clad layer surrounding the core part about an optical axis of the core part, and an optical path conversion mirror formed at the end face of at least one of the core part or the clad layer. The method includes providing first servo bursts on a first track, measuring edge errors of the first servo bursts, and self-servo writing second servo bursts to a second track using different combinations of the edge errors to adjust the position error signals for the second servo bursts. The voltage of the power supply is 4. The composite radius filler is made structural by a nanostructure arranged within the composite radius filler for the reinforcement of the interface between the radius filler and the structural composite part. Various components are adjustable to allow the configuration of the completed gutter guard to be adjusted as desired.