Abstract: Broad bandwidth source(BBS) is usually used to watch and control the fabrication of fiber gratings.A home-made Yb3+-doped double-cladding fiber superfluorescent broad bandwidth source is reported.The BBS,with bandwidth of about 75nm at the maximum output power,is pumped by a 971nm laser diode.The BBS outputs high power with a flat superfluorescent spectrum in the range of 10nm near the central wavelength of 1085nm.Then the BBS is used to watch and control the fabrication of single-mode and multi-mode fiber Bragg gratings and the results are satisfied.