Watt-Level Temporal Stable and Wavelength Flexible Amplified Broadband Light in a Raman Amplifier Pumped by a Tunable Random Fiber Laser

We demonstrate a new method to achieve high-power and wavelength flexible broadband light based on a random fiber laser (RFL)-pumped Raman amplifier seeded by a superluminescent diode (SLD). Benefiting from the wavelength flexibility of the RFL and the broadband Raman gain, the amplified broadband light with watt-level output power and continuously tunable central wavelength could be realized. As a verification, an in-house built cascaded RFL with a wavelength tuning range of 1210–1270 nm is employed as the pump source of the Raman amplifier, and a 1.3 μm broadband SLD source is used as seed light. As a result, the amplified broadband light with the 3 dB bandwidth of 13 nm, output power of 1 W and the tunable central wavelength in 1315–1340 nm is realized. Good temporal stability of the amplified broadband light is also demonstrated due to the use of low-noise Raman amplification in a backward pumping scheme. The method for further power scaling of the broadband light to 10-watt level is also numerically studied. The proposed method paves a new way for high-power and wavelength flexible broadband light amplification, which could be used as powerful sources to improve the system performances of optical coherence tomography, optical fiber communications, interferometric diffusing wave spectroscopy, fiber optic gyroscopes, etc.