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 invention prevents electrostatic discharge damage by providing a means for grounding a lead to a controlled ground potential. At least a portion of one of the first surface area and the second surface area comprises an air permeable surface area having a predetermined airflow rate such that the heat generating agent remains substantially evenly distributed within the pouch.