Fiber Bragg gratings in polarization maintaining specialty fiber for Raman fiber lasers

Highly Stable PM Raman Fiber Laser at 1680 nm

“…FBG 1 and FBG 2 define the laser cavity, whereas FBG 3 acts as a pump reflector that provides increased pump efficiency through dual pass amplification. FBG 1,3 has an estimated reflectivity R > 99% and FWHM of 135 pm. The output FBG 2 is estimated to have a reflectivity of 5 dB and FWHM of 28 pm.…”

“…Distributed Bragg reflector (DBR) Raman fiber lasers (RFL) operating outside the wavelength bands covered by typical rare-earth doped fiber lasers, have recently been demonstrated with pm linewidths (LW) [1,2], along with distributed feedback RFL's enabling further LW reduction [3]. Narrow spectral LW and stable linear output polarization are required for applications, such as second harmonic generation, spectroscopy and wavelength (WL) conversion [4].…”

PM Raman fiber laser at 1679 nm

“…Since the pump power is quickly depleted in a RFL, a single pass configuration has been suggested [4]. We have investigated both a single-and double-pass pumped cavity of 61 m, results shown in Fig.…”

“…1a) and second, the Raman gain coefficient which reduces with increasing wavelength, more specifically the Raman gain coefficient scales inversely with wavelength, when ignoring any wavelength effect on the effective area of the fiber. To investigate the impact of these drawbacks on a Raman laser we constructed a fiber laser based on the configuration in [4,5]. As a result we demonstrate that in spite of the before mentioned drawbacks we were able to achieve a Raman resonator with a slope efficiency of 67 % and a threshold power of 850 mW, and we produced an output power exceeding 270 mW.…”