US Patent 8002478 Optical sub-assembly with glass member physically contact with external fiber

An optical receptacle that enhances the optical coupling tolerance is disclosed. The optical receptacle of the invention provides, in stead of the coupling fiber installed in a conventional optical receptacle, a glass member with a diameter substantially equal to the diameter of the external fiber. The glass member, which is held by the support, provides a convex surface that abuts against the top of the external ferrule and another surface inclined with the optical axis to prevent the light reflected thereat from returning the optical device. The glass member has a substantially homogeneous distribution in the refractive index thereof; accordingly, the fluctuation in the optical coupling with the external ferrule may be reduced.