A 1- $\mu$ m Cylindrical Vector Beam Fiber Ring Laser Based on a Mode Selective Coupler

Abstract

Abstract-We propose and demonstrate a continuous-wave all-fiber ring laser generating cylindrical vector beams (CVBs) using a MSC as transverse mode converter and mode splitter. The MSC is fabricated by a novel method free of pre-tapering, achieving LP 11 mode with a high purity of > 96% near the wavelength of 1064 nm. The CVB fiber laser operates at a center wavelength of 1053.9 nm, with a 3 dB linewidth of less than 0.04 nm and a signal-to-background ratio of > 60 dB. The laser slope efficiency is > 9%. The radially and azimuthally polarized beams can be switched by adjusting the polarization controllers in the fiber ring cavity, with a high mode purity measured to be > 96%.Index Terms-Cylindrical vector beams, optical fiber lasers, mode converter. I. INTRODUCTIONhe cylindrical vector beams (CVBs) includes radially and azimuthally polarized beams [1]. Due to their characteristic of unique axial symmetry in both amplitude field and polarization, CVBs have been widely used in particle physics [2], optical tweezers [3], material processing [4] high-resolution metrology [5], and surface plasmon excitation [6]. Especially the radially polarized beam, which is attracting more and more attention.Various kinds of continuous-wave (CW) CVB generation techniques have been demonstrated with the use of certain spatial polarization selective elements introduced into the laser

Mode Coupling Analysis for a Mode Selective Coupler Using the Supermode Theory

“…As seen from Figure 5a,b, the differences of the propagation constants |δ| calculated using the two methods match well with each other when the core radius a 1 varies from 3 µm to 4.9 µm, while there is a notable calculation error for the coupling coefficient κ when a 1 is smaller than ~4.2 µm, which is different from the results in Figure 4. This is also due to the error when we represent the supermodes as linear combinations of the individual modes supported by the single fiber waveguides, as shown in Equation (16). When a 1 deviates from the phase matching point (a 1 ≈ 4.493 µm), the error between the modal distributions of the supermodes and the linear combinations of the individual modes increases.…”

“…Mode selective couplers (MSCs) are key components of future mode division multiplexing (MDM) optical networks [1,2], which could be used in a mode multiplexer/ demultiplexer [3][4][5][6][7], few-mode fiber lasers [8][9][10][11][12][13][14][15][16], etc. Usually, an MSC consists of a singlemode-fiber (SMF) and a few-mode-fiber (FMF) whose cores are brought close together.…”

Dissipative soliton resonance Ytterbium-doped fiber laser with cylindrical vector beam generation

“…The SMF was firstly pre-tapered to about 80 um, then the well-prepared device was aligned and fused together with TMF using the modified flame method [16].…”

Generation of three-port splitter by double-layer grating in second-order Littrow configuration

“…Grating is a common optical device, which can perform different functions depending on the fabricated material and structure, such as polarization, splitting, filtering, etc. [1][2][3][4][5]. The grating can be designed as an anti-reflector [6], a phase retardation waveplate [7], a polarization beam splitter [8], and a wavelength selective reflection filter [9] according to different functions.…”