Optical fiber test equipment and optical fiber test method
An object of the present invention is to provide an optical fiber testing device and an optical fiber testing method capable of acquiring both unidirectional crosstalk and bidirectional crosstalk of an uncoupled multicore fiber in a short time and with a little man-hour. The optical fiber testing device 301 according to the present invention includes: the light input unit 10 configured to input test light to an arbitrary core at one end A of the uncoupled multicore fiber 50 ; the light receiving unit 20 configured to receive output light outputted from each core at the other end B of the uncoupled multicore fiber 50 by the test light and measure light intensity of the output light of each core; and the calculation unit 30 configured to calculate unidirectional transmission crosstalk in a case of performing unidirectional transmission, in which transmission directions of light beams are the same between two cores of the uncoupled multicore fiber 50 , from the light intensity of the output light, and calculate bidirectional transmission crosstalk in a case of performing bidirectional transmission, in which transmission directions of light beams are different between two cores of the uncoupled multicore fiber 50 , from the unidirectional transmission crosstalk.
1 . An optical fiber testing device comprising:
a light input unit configured to input test light to an arbitrary core at one end of an uncoupled multicore fiber;
a light receiving unit configured to receive output light outputted from each core at an other end of the uncoupled multicore fiber by the test light and measure light intensity of the output light of each core; and
a calculation unit configured to calculate unidirectional transmission crosstalk in a case of performing unidirectional transmission, in which transmission directions of light beams are same between two cores of the uncoupled multicore fiber, from the light intensity of the output light, and calculate bidirectional transmission crosstalk in a case of performing bidirectional transmission, in which transmission directions of light beams are different between the two cores of the uncoupled multicore fiber, from the unidirectional transmission crosstalk.
2 . The optical fiber testing device according to claim 1 , wherein the calculation unit is further configured to:
calculate the unidirectional transmission crosstalk from light intensity of the output light of the one core and light intensity of the output light of another core;
calculate a power coupling coefficient from the unidirectional transmission crosstalk; and
calculate the bidirectional transmission crosstalk by substituting a Rayleigh scattering coefficient, a backscattered light capturing rate, and a loss coefficient into a power coupling equation of Expression C1:
[
Expression
C
1
]
X
T
b
≅
α
s
α
Bh
[
sinh
(
α
L
)
α
-
L
exp
(
-
α
L
)
]
(
C
1
)
where α is the loss coefficient, α s is the Rayleigh scattering coefficient, B is the backscattered light capturing rate, h is the power coupling coefficient, and L is a fiber length of the uncoupled multicore fiber.
3 . An optical fiber testing method comprising:
inputting test light to an arbitrary core at one end of an uncoupled multicore fiber;
receiving output light outputted from each core at an other end of the uncoupled multicore fiber by the test light and measuring light intensity of the output light of each core;
calculating unidirectional transmission crosstalk in a case of performing unidirectional transmission, in which transmission directions of light beams are same between two cores of the uncoupled multicore fiber, from the light intensity of the output light; and
calculating bidirectional transmission crosstalk in a case of performing bidirectional transmission, in which transmission directions of light beams are different between the two cores of the uncoupled multicore fiber, from the unidirectional transmission crosstalk.
4 . The optical fiber testing method according to claim 3 , further comprising:
calculating the unidirectional transmission crosstalk from light intensity of the output light of the one core and light intensity of the output light of another core;
calculating a power coupling coefficient from the unidirectional transmission crosstalk; and
calculating the bidirectional transmission crosstalk by substituting a Rayleigh scattering coefficient, a backscattered light capturing rate, and a loss coefficient into a power coupling equation of Expression C1:
[
Expression
C
1
]
X
T
b
≅
α
s
α
Bh
[
sinh
(
α
L
)
α
-
L
exp
(
-
α
L
)
]
(
C
1
)
where α is the loss coefficient, α s is the Rayleigh scattering coefficient, B is the backscattered light capturing rate, h is the power coupling coefficient, and L is a fiber length of the uncoupled multicore fiber.