Low quantum defect random Raman fiber laser

Abstract

The random Raman fiber laser (RRFL) has attracted great attention due to its wide applications in optical telecommunication, sensing, and imaging. The quantum defect (QD), as the main source of thermal load in fiber lasers, could threaten the stability and reliability of the RRFL. Conventional RRFLs generally adopt silica fiber to provide Raman gain, and the QD exceeds 4%. In this letter, we propose and demonstrate a phosphosilicate-fiber-based low-QD RRFL. There is a strong boson peak located at the frequency shift of 3.65 THz in the phosphosilicate fiber we employed. By utilizing this boson peak to provide Raman gain, we demonstrated an 11.71 W temporally stable random Raman laser at 1080 nm under a pump wavelength of 1066 nm. The corresponding QD is 1.3%, less than one third of the QD of the common silica-fiber-based RRFL. Compared with the full-cavity low-QD Raman fiber laser, this cavity-less low-QD RRFL has lower and flatter noise in the high frequency area (>100 kHz). This work provides a reference for suppressing thermal-induced effects, such as thermal-induced mode instability, thermal noise, and even fiber fusing in RRFLs.

Spectral Manipulations of Random Fiber Lasers: Principles, Characteristics, and Applications

“…[126][127][128][129][130] Meanwhile, based on the boson peak, a phosphosilicate fiber-based RRFL with a quantum defect of only 1.3% was demonstrated, which possesses the potential to be used for suppressing thermal-induced effects in RRFLs. [131]…”

Pulse-Profile-Maintaining Characteristics of Gain-Switched Nanosecond Raman Fiber Laser and Amplifier

“…Considering that the Raman threshold has been reached, there should be some newly produced CW Raman light besides the pulsed Raman light produced during the PDC. The continuous wave Raman light is produced during the backward pumping and then reflected back as the output through the distributed feedback Rayleigh scattering effect [31,32]. But temporally we do not have proper equipment to measure how much power is contained as the CW.…”