Demonstration of a 3 mW threshold Er-doped random fiber laser based on a unique fiber Bragg grating

Abstract

We demonstrate a novel random laser based on a single fiber Bragg grating. A long fiber Bragg grating fabrication technique allows the insertion of a large number of randomly distributed phase errors in the structure of the grating which induces light localization. By writing such a grating in a polarisation maintaining Er-doped fiber, a random laser is demonstrated by pumping the fiber with 976 and 1480 nm pump lasers. The number of emitted modes is observed to be a function of the length of the grating and of the pump power and single-mode operation is shown to be possible. The random fiber laser shows low-threshold (approximately 3 mW) and measured approximately 0.5 pm emission linewidth at a wavelength of around 1534 nm.

Lévy Statistics and Glassy Behavior of Light in Random Fiber Lasers

“…As reported by Gagné and Kashyap [45], a unique FBG was produced by writing an exceptionally high number of gratings (>> 1000) over a 30 cm length fiber. A polarization-maintaining erbium-doped fiber from CorActive (peak absorption 28 dB/m at 1530 nm, NA 0.25, mode field diameter 5.7 μm) was employed, in which the randomly distributed phase errors grating was written, instead of a random array of gratings as in [44].…”

“…Several tens to hundreds of gratings can be inscribed along several tens of cm of fiber length. In the next section, we will describe the fabrication and characterization of the Er-RFL with a specially-designed FBG used [45] to study the Lévy-like statistics and observation of the replica-symmetry-breaking phenomenon, which marks the signature of the phase transition from a photonic paramagnetic to a photonic spin-glass phase.…”

“…A polarization-maintaining erbium-doped fiber from CorActive (peak absorption 28 dB/m at 1530 nm, NA 0.25, mode field diameter 5.7 μm) was employed, in which the randomly distributed phase errors grating was written, instead of a random array of gratings as in [44]. It was realized in [45] that during the movement of the translation stage, the friction between the fiber and the mount introduced irregularities in the grating spectrum that could be controlled by managing the air flow from the vacuum. Such irregularities were perceived as small phase errors, randomly but continuously distributed along the grating profile being inscribed.…”

“…Thanks to this procedure, a very high number of modes was possible, which is very important for several applications, as we will see later. The Er-RFL described in [45] had a very low threshold of 3 mW, with a throughput efficiency of ~4.5 % for 100 mW pump power. The number of emitted modes was dependent on the pump power and fiber length (20 or 30 cm fiber lengths were characterized in [45]), and a single or few modes were observed, limited by the system measurement resolution [69].…”

Multi-parameter sensor based on random fiber lasers

“…The 1-D optical fiber waveguide provides good confinement in the transverse directions of the light rays trapped inside and effective one-dimension random feedback. RFLs have been realized using Er-doped fiber gain, Raman gain, and Brillouin gain with random feedback induced by Rayleigh scattering, [16][17][18][19][20][21] or artificially induced randomness such as a photonic crystal fiber filled with a suspension structure, 22 Bragg gratings in rare-earth doped fiber, 23 and polymer optical fiber. 24 Either in-coherent or coherent lasing outputs have been observed in these random lasing systems, with lasing spectra of bell-shaped peaks as broad as terahertz level 25 or even narrow spikes as sharp as sub-kilohertz.…”