Fig. 1. Experimental setup of on-demand mode laser. PL, 980 nm pump laser; ISO, isolator; Col, fiber collimator; Fi, filter; Pol, polarizer; SMF, single-mode fiber.

Fig. 2. (a) Phase setting of superpixel cell, (b) multi-mode mask optimized by superpixel for excitation of the LP21 mode, (c) the simulation results of the simultaneous excitation of the LP01 and LP21 modes, (d), (e) the simulation results for the generation of the LP74 and LP105 modes, respectively, (f) the simultaneous excitation of the LP01 and LP21 modes by using the multi-mode mask in the experiment.

Fig. 3. Examples of higher-order mode output from the on-demand mode laser.

Fig. 4. Optical intensity distributions of the LP01, LP11, LP21, and LP02 modes before and after propagation in four-mode FMF. (a) The intensity distributions before propagation, captured by a CCD located in the focal point of the lens, and (b) the far-field intensity distributions after propagation in 100 m FMF.

Fig. 5. (a) Measured spectrum of the mode generated from the on-demand mode laser and (b) the quantum efficiency of the LP21 mode.