Title :
Fiber Ring With Long Delay Used as a Cavity Mirror for Narrowing Fiber Laser
Author :
Zhengqing Pan ; Qing Ye ; Haiwen Cai ; Ronghui Qu ; Zujie Fang
Author_Institution :
Shanghai Key Lab. of All Solid-State Laser & Appl. Tech., Shanghai Inst. of Opt. & Fine Mech., Shanghai, China
Abstract :
A fiber ring with an extremely low reflectivity fiber Bragg grating inserted as a slow-light component is proposed and demonstrated to be used as a cavity mirror with long delay for narrowing fiber laser linewidth. Due to the recirculating propagation and resonance in the ring composed of a low split ratio coupler, the composite ring provides not only a high enough reflectivity and extremely narrow bandwidth for laser oscillation, but also an enlarged group delay. The effective reflectance and group delay of the composite ring are discussed theoretically. Its effect of laser linewidth narrowing is verified experimentally in a laser with the composite fiber ring and a high reflectivity fiber Bragg grating as cavity mirrors. Its line shape, relative intensity noise (RIN), and frequency noise (FN) are measured, showing the full-width at half-maximum linewidth of 150 Hz, RIN and FN of less than -125 dB/Hz at 500 Hz and 30 Hz/√Hz at 500 Hz, respectively.
Keywords :
Bragg gratings; fibre lasers; laser cavity resonators; laser mirrors; laser noise; laser variables measurement; optical delay lines; optical fibre couplers; reflectivity; spectral line narrowing; cavity mirror; composite fiber ring; extremely low reflectivity fiber Bragg grating; fiber laser linewidth narrowing; fiber laser oscillation; frequency 150 Hz; frequency 500 Hz; frequency noise measurement; full-width at half-maximum linewidth; high reflectivity fiber Bragg grating; line shape measurement; optical delay; relative intensity noise measurement; slow-light component; split ratio coupler; Cavity resonators; Fiber lasers; Laser noise; Measurement by laser beam; Optical fiber couplers; Reflectivity; Fiber laser; effective cavity length; fiber Bragg grating; fiber ring;
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2014.2329302
