Device, method and system for calculating power coupling coefficients between cores
A device according to the present disclosure: acquires a group delay time difference between eigenmodes, at a specific wavelength, in a coupled two-core fiber; acquires spatial mode dispersion between the eigenmodes, at the specific wavelength, in the coupled two-core fiber; and calculates an average power coupling coefficient between cores, at the specific wavelength, within an entire length of the coupled two-core fiber by using the group delay time difference, the spatial mode dispersion, and a length of the coupled two-core fiber.
1 . A method comprising:
acquiring a group delay time difference between eigenmodes, at a specific wavelength, in a coupled two-core fiber;
acquiring spatial mode dispersion between the eigenmodes, at the specific wavelength, in the coupled two-core fiber;
calculating an average power coupling coefficient between cores, at the specific wavelength, within an entire length of the coupled two-core fiber by using the group delay time difference, the spatial mode dispersion, and a length of the coupled two-core fiber, wherein the power coupling coefficient is calculated by using Expression C2,
[
Math
.
C2
]
Δ
τ
=
d
Δ
β
d
ω
L
h
(
C2
)
where Δ τ represents the spatial mode dispersion between the eigenmodes, at the specific wavelength, in the coupled two-core fiber, dΔβ/dω represents the group delay time difference between the eigenmodes, at the specific wavelength, in the coupled two-core fiber, L represents a fiber length of the coupled two-core fiber, and h represents a power coupling coefficient between cores; and
optimizing design of the coupled two-core fiber using the power coupling coefficient.
2 . A system that calculates a power coupling coefficient between cores of a coupled two-core fiber, the system comprising:
a light source configured to inject light into the coupled two-core fiber;
a light receiving unit configured to receive light propagating through the coupled two-core fiber;
a processor interfaced with the light receiving unit; and
a storage medium having computer program instructions stored thereon, when executed by the processor, perform to:
acquire a group delay time difference between eigenmodes, at a specific wavelength, in a coupled two-core fiber using the light injected by the light source and received by the light receiving unit;
acquire spatial mode dispersion between the eigenmodes, at the specific wavelength, in the coupled two-core fiber using the light injected by the light source and received by the light receiving unit; and
calculate an average power coupling coefficient between cores, at the specific wavelength, within an entire length of the coupled two-core fiber by using the group delay time difference, the spatial mode dispersion, and a length of the coupled two-core fiber, wherein the power coupling coefficient is calculated by using Expression C1,
[
Math
.
C1
]
Δ
τ
=
d
Δ
β
d
ω
L
h
(
C1
)
where Δ τ represents the spatial mode dispersion between the eigenmodes, at the specific wavelength, in the coupled two-core fiber, dΔβ/dω represents the group delay time difference between the eigenmodes, at the specific wavelength, in the coupled two-core fiber, L represents a fiber length of the coupled two-core fiber, and h represents a power coupling coefficient between cores.
3 . The system according to claim 2 , wherein the coupled two-core fiber has a length in which an impulse response width is widened in proportion to a square root of a distance.
4 . The system according to claim 2 , wherein the computer program instructions further perform to
acquire the group delay time difference, at different wavelengths, individually
acquire the spatial mode dispersion, at different wavelengths, individually, and
calculate the power coupling coefficient, at a wavelength at which both the group delay time difference and the spatial mode dispersion are acquired.