Improved Raman Fiber Laser (RFL) generators may include a mid-infrared fiber, e.g., a fiber comprising a tellurite glass, a chalcogenide glass, a fluoride glass, or similar material. A phase-shifted fiber Bragg grating may be inscribed in the fiber. A pump laser generator may be coupled with the fiber in order to supply a pump laser to the fiber. When stimulated by the pump laser, the RFL generator may emit an output laser having a mid-infrared wavelength. A tuner may be used to tune the output laser.