Ferrule and ferrule structure

A ferrule comprising:

• a main body including an inner wall, an outer wall, and a connection end surface at which a tip of an optical fiber is to be disposed, wherein the inner wall has fiber holes through which the optical fiber is inserted toward the connection end surface;
• an adhesive filling part disposed in the main body on an opposite side from the connection end surface with respect to the inner wall;
• an upper opening that opens from the outer wall to the adhesive filling part;
• and
• a lower opening that opens from the outer wall to the adhesive filling part and is disposed on an opposite side from the upper opening, wherein
• the inner wall has a first surface and a second surface protruding toward the adhesive filling part from the first surface,
• the upper opening is opened in a location along the first surface, and
• the lower opening is opened in a location along the second surface.

A ferrule comprising:

• a main body including an inner wall, an outer wall, and a connection end surface at which a tip of an optical fiber is to be disposed, wherein the inner wall has fiber holes through which the optical fiber is inserted toward the connection end surface;
• an adhesive filling part disposed in the main body on an opposite side from the connection end surface with respect to the inner wall;
• an upper opening that opens from the outer wall to the adhesive filling part;
• and
• a lower opening that opens from the outer wall to the adhesive filling part and is disposed on an opposite side from the upper opening, wherein
• the inner wall has:
• a first surface along an edge of the upper opening on a side of the connection end surface,
• a second surface protruding toward the adhesive filling part from the first surface, and
• a third surface disposed on an opposite side from the upper opening with respect to the second surface and on the side of the connection end surface with respect to the second surface.