Graded-index fiber

Mode volume

Long-period fiber grating

Fiber Bragg grating

Optics

Fiber optic sensor

Quantum mechanics

Composite material

Fiber

Single-mode optical fiber

Angular momentum

Optical fiber

Grating

Materials science

Physics

Optics Letters

An all-fiber orbital angular momentum (OAM) mode generator enabling simultaneous generation of the second- and the third-order OAM modes with conversion efficiencies larger than 95% has been proposed and experimentally demonstrated, which is realized by using a high-order helical long-period fiber grating (HLPG) written in a thinned four-mode fiber. This is the first time, to the best of our knowledge, that two such OAM modes have been simultaneously obtained at wavelengths ranging from 1450 to 1620 nm by using only one fiber component, i.e., the HLPG. The proposed method provides a new way to simultaneously generate different orders of the OAM modes, which would further expand the OAM’s applications to the fields of the optical tweezers, microscopy, and fiber communication, etc.

Simultaneous generation of the second- and third-order OAM modes by using a high-order helical long-period fiber grating