The fiber lens is used to couple light from the laser diode, and with good matching between the divergence of laser chip and fiber lens, coupling efficiency as high as 90% could be achieved. The FBG is used to form an external feedback structure, which will stabilize the output laser around the center wavelength of the FBG, and meanwhile narrow the laser output spectrum. Besides, due to the low thermal dependence of FBG, the thermal stability of the laser output is also greatly improved. Therefore, high pumping efficiency as well as good pumping stability of the pump laser could be achieved.
Raysung is one of the only manufacturers in the world who have the capacity to manufacture the type of optical fiber which incorporates FBG and lensed fiber. The minimum distance between the lensed fiber and FBG can be controlled within 1.5mm. This type of fiber can be used as cavity resonator in the application of fiber laser and also stabilizator for pump laser.