Abstract: A ferrule product 30b is utilized in an optical module 5 comprising a semiconductor optical amplifier 55 having a pair of end facets. The ferrule product 30b comprises an optical fiber 51 and a ferrule 52. The optical fiber 51 has one end part, optically coupled with one of the pair of end facets, a first part including a grating 511 disposed at a predetermined position separated from one end part, and a second part different from the first part. The ferrule 52 has a capillary part 521 for holding the optical fiber 51 and a flange part 522 for holding the capillary part. The flange part 522 is disposed on the second part.