Patent ID: 7920767

Claim:
An optical fiber having at least a segment that is bent, said bent segment comprising: a core region having a longitudinal axis, and a cladding region surrounding said core region, said core and cladding regions configured to support and guide the propagation of signal light in a fundamental transverse mode and at least one higher-order transverse mode, said modes propagating in said core region in essentially the direction of said axis, said cladding region comprising: an outer cladding region, an annular trench region disposed between said core region and said outer cladding region, at least one axially-extending pedestal region disposed within said trench region being configured (i) to support the propagation of at least one transverse mode of said at least one pedestal region, and (ii) to resonantly couple the at least one higher order transverse mode of said core region to the at least one transverse mode of said at least one pedestal region, wherein said resonant coupling is precompensated for effects from said bending; and wherein the refractive index n ped of said at least one axially-extending pedestal region is selected to pre-compensate for an expected bend-induced shift in the equivalent index of said pedestal region wherein said shift is equivalent to 0.8n ped (R ped /R bend ), where R ped is the distance of the center of said pedestal region from said axis and R bend is the radius of said bent segment.