Few-mode fiber Bragg grating-based multi-wavelength fiber laser with tunable orbital angular momentum beam output

Abstract

We experimentally demonstrate a multiwavelength fiber ring laser with tunable orbital angular momentum (OAM) beam output. The laser is embedded with a few-mode fiber Bragg grating and a mode selective coupler (MSC). The mode conversion from LP01 mode to LP11 mode is realized by using the MSC as a mode converter. By rotating a polarizer set at the output end of the MSC, the topological charge of the OAM beam can be tuned from l = −1 to l = +1 and thus a tunable OAM beam is obtained. By adjusting the polarization controllers (PCs), the laser can operate under single-, dual- and triple-wavelength lasing conditions.

Spectral optimization of Stokes channels for multi-wavelength Brillouin fiber lasers

“…Initially, figure 2 depicts the saturation curve employed for the amplifier gain obtained from equation (12), which corresponds to a 10 m erbium-doped fiber [(EDF)-Thorlabs-M12-980-125] pumped by a 280 mW tunable laser source at 1474 nm. This is the exact EDFA condition over which we choose to run our simulations, and it was used unchanged throughout all optimization we performed in this work.…”

“…In equation (12), G max is the amplifier's maximum gain, P in is its input power, and P sat is the saturation power. The parameters a and b are real numbers calculated to fit the simulated curve to the measured experimental data, as will be shown later in figure 3 in the results section.…”

“…low intracavitary losses, mechanical robustness, and compact structures. Some multi-wavelength fiber laser architectures can be built by employing fiber Bragg gratings [12], Mach-Zehnder interferometers [13], Sagnac fiber loop filters [14], Lyot filters [15], Fabry-Perot filters [16], nonlinear optical loop mirrors [17], and also very often nonlinear effects such as nonlinear polarization rotation effect [18], four-wave mixing [19], and stimulated Brillouin scattering (SBS) [20].…”

Double-groove reflection grating for three-channel beam separation at infrared wavelength

“…In numerous laser systems [1][2][3], the diffraction grating is a very important binary optical device [4][5][6][7][8]. It can be used in fiber Bragg elements [9,10], optical communication [11,12], a laser modulation interferometer [13][14][15] and holographic technology [16].…”

High power narrow linewidth LP11 mode fiber laser using mode-selective FBGs

“…Currently, many methods have been adopted to generate a single higher-order transverse mode laser, e.g. spatial light modulators [7][8][9][10], spatially variant waveplates [11,12], mode converters [13,14], fiber Bragg grating (FBG) [2,[15][16][17][18][19], polarization controllers [20,21], coherent polarization beam combination [22], etc. Most of the methods mentioned above are based on bulk components.…”