Patent ID: 8270787
Filing Date: 2012-09-18
Classification: G02B

Abstract:
1. An optical fiber coupler, comprising: an input section of optical fiber for supporting the propagation of a fundamental mode of an optical signal along a longitudinal axis thereof; a substantially adiabatic transition section of optical fiber coupled to an output of the input section, the substantially adiabatic transition section of optical fiber having a radius r and a radius of curvature R that are controlled to shift the propagating fundamental mode of the optical signal into an outer peripheral region of the substantially adiabatic transition section; and an output section of optical fiber coupled to an output of the substantially adiabatic transition section for receiving the shifted propagating optical signal, wherein the substantially adiabatic transition section of optical fiber is curved to form a coil, the coil exhibiting an expanding radius r(·) to maintain propagation of the fundamental mode from the output of the input section to the input of the output section.