Patent ID: 8002478

Claim:
An optical sub-assembly optically coupleable with an external fiber that provides a ferrule in an end of said external fiber, comprising: an optical receptacle including a glass member having a substantially homogeneous distribution of refractive index and a diameter substantially equal to a diameter of said external fiber, said glass member coming in physical contact with said external fiber; a holder having a first bore, a second bore connected to said first bore, and a third bore, said first bore having a diameter slightly larger than a diameter of said glass member to hold said glass member, a sleeve arranged to receive said ferrule in one side thereof and said holder in another side thereof, and a shell including a support portion and a joint portion, said support portion holding said holder with said glass member and said sleeve; and an optical device that installs a semiconductor optical device, said optical device being held by said joint portion of said shell, wherein said second bore of said holder has a diameter greater than said diameter of said first bore to form a gap between said glass member and an inner wall of said second bore, wherein said third bore of said holder has a diameter greater than said diameter of said second bore, and wherein said glass member has an end surface facing said optical device positioned in said third bore.