Optical fiber holding structure, optical transmission module, and method of manufacturing optical fiber holding structure

An optical fiber holding structure for being mounted on a substrate equipped with an optical element that includes a light receiving unit inputting an optical signal or a light emitting unit outputting an optical signal such that the optical fiber holding structure faces the optical element via the substrate, the optical fiber holding structure being configured to hold an optical fiber that transmits the optical signal to or from the optical element, the optical fiber holding structure comprising:

• a structure main body having a prismatic shape;
• a through hole into which the optical fiber is inserted;
• a protruding portion having a columnar shape projecting from the structure main body and configured to be inserted into an opening portion of the substrate;
• and
• a contact portion configured to abut on a surface of the substrate to position the optical element and the optical fiber at a predetermined distance, wherein
• the through hole is formed so as to penetrate from a surface of the structure main body through which the optical fiber is inserted to an end surface of the protruding portion, and
• at least one side surface of the structure main body is flush with at least one side surface of the protruding portion.