Isolating backward Raman signal in high-power narrowband MOPA fiber laser using CTFBGs

Here, we firstly report the stimulated Raman scattering (SRS) suppression in high-power narrow-band MOPA fiber lasers using chirped and tilted fiber Bragg gratings (CTFBGs). By inserting a CTFBG between the seed laser and the amplifier stage, the backward Raman signal is strongly isolated, meanwhile the forward SRS is well suppressed. Experimental results imply that traditional bulky isolator can be replaced by compact CTFBG, what's more CTFBG has much lower insertion loss and much higher power capacity. © 2020 The Author(s).