Open AccessFrequency- and intensity-noise suppression in Yb^3+-doped single-frequency fiber laser by a passive optical-feedback loop
Author(s) -
Yanbing Hou,
Qian Zhang,
Pu Wang
Publication year - 2016
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.24.012991
Subject(s) - relative intensity noise , laser linewidth , optics , materials science , fiber bragg grating , fiber laser , phase noise , noise (video) , laser , semiconductor laser theory , optoelectronics , physics , artificial intelligence , computer science , image (mathematics)
The frequency and intensity noise of an Yb 3+ -doped single-frequency distributed Bragg reflector (DBR) fiber laser are effectively reduced by a simple, passive optical-feedback loop (POFL), which consists of only two optical couplers. The feedback loop, which has resonance with the high reflective grating of the DBR laser and relative long optical path compared to the DBR cavity, results in narrower linewidth and lower relative intensity noise (RIN) in the feedback signal. The RIN of relaxation oscillation is reduced by 20dB from -99.9dB/Hz @ 993 kHz to -119.4dB/Hz @ 192 kHz, and the frequency noise was suppressed at frequencies higher than 1 kHz, with a maximum reduction of about 30 dB from 10 kHz to 100 kHz, which results in a spectral linewidth compression from 3.96 kHz to 540 Hz. Even after one fiber amplification stage, the noise did not increase significantly, and a spectral linewidth well below 1 kHz were also achieved at output power of 10W.