<title>A novel all-fiber self-organization coherent erbium-doped fiber laser</title>

Abstract

A novel all-fiber self-organization Michelson coherent Erbium-doped fiber laser (MCEDFL) has been proposed and demonstrated. The laser system is composed of two independent branch lasers. The two arms of the active interferometer are spliced to a 3dB 2×2 coupler. A fiber Bragg Grating (FBG) with 95% reflectivity is spliced to one port of the coupler. It acts as wavelength selective filter and common reflection mirror to make the two branch arms emit laser with the same wavelength, which can conform to the coherent constraint exactly. The high reflection mirror of each laser cavity is composed of a 3dB fiber loop mirror (FLM). The other output port of the coupler is spliced to an isolator that acts as the MCEDFL's output port. Any feedback from this port into the MCEDFL is prevented by the isolator. When each of the two lasers is pumped to 100mW independently, the output power is 12.1mW and 16.2mW respectively. By adjusting the polarization controller (PC), the two lasers attain coherent coupling, the output power is 34.5mW, which is more than two times the output power of any single laser. Furthermore, we bring forward and discuss a novel factor to denote the effect of coherent combination—coherent coupling factor. Herein the value of coherent factor is 1.12. The advantages of the coherent fiber, such as simple structure, high efficiency and single frequency etc, can make coherent coupling easier.