Multiwavelength synchronously Q-switched Erbium-doped fiber laser based on the adjustment of the free spectral range of an intracavity tapered-fiber filter

Abstract

All-fiber multiwavelength Q-switched (MWQS) lasers are of huge interest because of their emergent and well-known scientific and technological applications. Passive all-fiber MWQS lasers require a saturable absorber to generate Q-switched pulses and an optical filter to seed the multiwavelength regime. New trends in all-fiber MWQS lasers demand new devices to explore innovative configurations and capabilities in this kind of lasers. In this sense, we report on the experimental demonstration of a multiwavelength synchronously Q-switched Erbium-doped fiber laser (QSEDFL). This laser achieves dual and triple wavelength lasing around 1530 nm with interchangeable wavelength separation. A shorth piece of Tm:Ho co-doped fiber is the saturable absorber. An intracavity tapered optical fiber filter in a double-pass configuration allows the versatile process of wavelength filtering, enabling the adjustment of wavelength lasing separation between 1.7 nm, 2.1 nm, and 2.5 nm with synchronized pulses of each wavelength component. This proposal offers a new route to all-fiber multiwavelength synchronously Q-switched laser with potential applications for WDM systems and all-fiber sensors.