Invention Publication
- Patent Title: MODE CONVERSION DEVICE AND DESIGN METHOD
-
Application No.: US18277320Application Date: 2021-02-17
-
Publication No.: US20240142696A1Publication Date: 2024-05-02
- Inventor: Yoko YAMASHITA , Takayoshi MORI , Takashi MATSUI , Kazuhide NAKAJIMA
- Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
- Applicant Address: JP Tokyo
- Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION,NIPPON TELEGRAPH AND TELEPHONE CORPORATION
- Current Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION,NIPPON TELEGRAPH AND TELEPHONE CORPORATION
- Current Assignee Address: JP Tokyo; JP Tokyo
- International Application: PCT/JP2021/005851 2021.02.17
- Date entered country: 2023-08-15
- Main IPC: G02B6/02
- IPC: G02B6/02 ; G02B27/00
Abstract:
An objective of the present invention is to provide a mode conversion device capable of designing any coupling efficiency and full width at half maximum, and a design method therefor.
According to the present invention, a mode conversion device includes a long period grating at a core of an optical fiber through which light is able to propagate in at least two propagation modes. The long period grating satisfies a relationship of Expression C1, where a full width at half maximum FWHM is a wavelength band in which the coupling efficiency is a half of coupling efficiency of mode conversion at a center wavelength, C is coupling efficiency, Lc is a complete coupling length, Lg is a grating length, Λ is a grating pitch, and Δβ is a propagation constant difference between the two propagation modes at the center wavelength of a mode conversion target.
[
Math
.
C
1
]
Λ
=
2
π
Δβ
C
=
sin
2
(
π
2
L
g
L
c
)
FWHM
·
L
c
=
b
❘
"\[LeftBracketingBar]"
d
Δ
β
d
λ
❘
"\[RightBracketingBar]"
-
1
b
=
-
1169.3
C
+
1705.6
(
C
1
)
According to the present invention, a mode conversion device includes a long period grating at a core of an optical fiber through which light is able to propagate in at least two propagation modes. The long period grating satisfies a relationship of Expression C1, where a full width at half maximum FWHM is a wavelength band in which the coupling efficiency is a half of coupling efficiency of mode conversion at a center wavelength, C is coupling efficiency, Lc is a complete coupling length, Lg is a grating length, Λ is a grating pitch, and Δβ is a propagation constant difference between the two propagation modes at the center wavelength of a mode conversion target.
[
Math
.
C
1
]
Λ
=
2
π
Δβ
C
=
sin
2
(
π
2
L
g
L
c
)
FWHM
·
L
c
=
b
❘
"\[LeftBracketingBar]"
d
Δ
β
d
λ
❘
"\[RightBracketingBar]"
-
1
b
=
-
1169.3
C
+
1705.6
(
C
1
)
Information query
