Patent ID: 9507082
Filing Date: 2016-11-29
CPC Classification: G02B

Claim Text:
1. A two-mode optical fiber for propagating an LP01 mode and an LP11 mode which are components of a signal light, said two-mode optical fiber comprising: an inner core having an αth-power-type refractive index distribution and a maximum refractive index of n an outer core surrounding the inner core and having a refractive index of n a clad surrounding the outer core and having a refractive index of n wherein a mode dispersion Δτ defined by the following mathematical formula (2) is constant in a predetermined wavelength band: wherein vg 11 represents a group velocity of the LP11 mode component and vg 01 represents a group velocity of the LP01 mode component, said two-mode optical fiber satisfying the following three conditions 1 to 3: where: a radius of the inner core is set to r a radius of an outer circumference of the outer core is set to a; a relative refractive index difference between the outer core and the clad is set to Δ−; a relative refractive index difference between the inner core and the clad is set to Δ+, Ra=r Rd=|Δ−|/|Δ+|.