Real time distributed temperature measurement of the gain fiber in all-fiber laser employing OFDR technology

Thermal effect of the gain fiber is one of the main factors which limit the power improvement of high power fiber lasers. Using traditional temperature measurement methods, we can only obtain the surface temperature of fiber while the core temperature cannot be detected. In this paper, the temperature of the gain fiber core in all-fiber laser is measured by optical frequency domain reflectometry(OFDR). The fiber laser is operating at 1080nm and the wavelength of detecting light emitted by OFDR is approximately 1550nm. The different wavelength of the two lasers has ensured the proper operating of fiber laser without effecting the operating lasers at 1080nm. The maximum output power of the fiber laser is 58.95W and results show that OFDR is a practical way to monitor the temperature of fiber laser system.