Patent ID: 8027557

Claim:
Optical fiber interconnection apparatus for optically coupling a source of optical energy having an output wavelength and an optical amplifier, comprising: an optical fiber arrangement having an input reference plane and an output reference plane, said arrangement comprising at least one intermediate section of optical fiber having a core spliced at first and second ends, respectively, to the cores of first and second sections of optical fiber, there being a first geometrical mismatch and a first numerical aperture mismatch between the core of the intermediate optical fiber and said core of said first section of fiber and a second geometrical mismatch and a second numerical aperture mismatch between said core of said intermediate section and said core of said third section of fiber, said mismatches being such that in the forward propagation direction wherein optical energy propagates from the input reference plane to said output reference plane, the geometrical mismatches are from smaller cross sectional area cores to larger cross sectional area cores and the numerical aperture mismatches are from larger numerical aperture cores to smaller numerical aperture cores and in the opposite direction of propagation, wherein optical energy propagates from said output reference plane to said input reference plane, the geometrical mismatches are from larger cross sectional area cores to smaller cross sectional area cores and the numerical aperture mismatches are from smaller numerical aperture cores to larger numerical aperture cores.