Optical fiber and laser device
An optical fiber, used in a laser device, propagates light having a wavelength of 1060 nm through a core in at least an LP01 mode and an LP11 mode. A difference between a propagation constant of light in the LP01 mode and a propagation constant of light in the LP11 mode is 1850 rad/m or more and 4000 rad/m or less.
1. An optical fiber used in a laser device, comprising:
a core, wherein
the optical fiber propagates light having a wavelength of 1060 nm through the core in at least an LP01 mode and an LP11 mode, and
a difference between a propagation constant of light in the LP01 mode and a propagation constant of light in the LP11 mode is 1850 rad/m or more and 4000 rad/m or less.
2. The optical fiber according to claim 1 , wherein
the difference between the propagation constant of light in the LP01 mode and the propagation constant of light in the LP11 mode is 2500 rad/m or less.
3. The optical fiber according to claim 1 , wherein
a refractive index profile of the core with respect to a cladding is stepwise,
the core has a diameter of 18 μm or more and 28.5 μm or less, and
a relative refractive index difference of the core with respect to the cladding is 0.1% or more and 0.2% or less.
4. The optical fiber according to claim 3 , wherein
the core has a diameter of 23 μm or more.
5. The optical fiber according to claim 1 , wherein
ytterbium is added to the core.
6. A laser device comprising an optical fiber, comprising:
a core, wherein
the optical fiber propagates light having a wavelength of 1060 nm through the core in at least an LP01 mode and an LP11 mode, and
a difference between a propagation constant of light in the LP01 mode and a propagation constant of light in the LP11 mode is 1850 rad/m or more and 4000 rad/m or less.
7. The laser device according to claim 6 , wherein
ytterbium is added to the core, and
pumping light is incident on the optical fiber.