Patent ID: 8419622

Claim:
An optical fiber connection structure for connecting a first optical fiber and a second optical fiber each of which is a multi-mode fiber having a core diameter of at least 100 μm, and for transmitting light having an optical power of at least 100 mW from said first optical fiber to said second optical fiber, said optical fiber connection structure comprising: a first graded-index fiber having a core diameter at least three times larger than that of said first optical fiber and being detachably attached to one end of said first optical fiber, said first graded-index fiber expanding a beam diameter of said light from said first optical fiber and collimating said light; a second graded-index fiber having a core diameter equal to or larger than that of said first graded-index fiber and being detachably attached to one end of said second optical fiber, said first graded-index fiber and said second graded-index fiber being spaced apart from each other with a predetermined gap, said second graded-index fiber converging said beam diameter of said light from said first graded-index fiber and causing said light enter said second optical fiber; a first connection member attached to said end of said first optical fiber such that said end of said first optical fiber is exposed from one end surface of said first connection member; a first optical component housing said first graded-index fiber such that a light incident surface and a light exit surface of said first graded-index fiber are exposed from both ends of said first optical component; a first holding member for holding said first connection member and said first optical component such that said end of said first optical fiber and said light incident surface of said first graded-index fiber are in contact with each other; a second connection member attached to said end of said second optical fiber such that said end of said second optical fiber is exposed from one end surface of said second connection member; a second optical component housing said second graded-index fiber such that a light incident surface and a light exit surface of said second graded-index fiber are exposed from both ends of said second optical component; a second holding member for holding said second connection member and said second optical component such that said end of said second optical fiber and said light exit surface of said second graded-index fiber are in contact with each other; and a joining member for joining said first optical component and said second optical component such that said light exit surface of said first graded-index fiber and said light incident surface of said second graded-index fiber are faced across with a predetermined gap; wherein the length of said first holding member is shorter than the total length of said first connection member and said first optical component, and the length of said second holding member is shorter than the total length of said second connection member and said second optical component.