Using Brillouin/Raman fiber laser (BRFL), we obtain an ultra-broadband (1433-1533nm) CW supercontinuum (SC) centered at 1484nm with maximum average output power of 1.87W and a nonlinear conversionefficiency of 81%. Spectral density of 18.4mW/nm is obtained. The BRFL consists of a Raman cavity withphosphosilicate fiber (PDF) and pairs of fiber Bragg grating (FBG) mirrors and a Brillouin cavity with the PDFand single-mode fiber (SMF), and feedback FBG mirror. With an 8.4W/1064nm Yb-doped double-clad fiberlaser (DCFL) as a pump and a 50% feedback FBG mirror at the end of the BRFL, an output power of over 1.7Wwith 100nm bandwidth centered at 1484nm and weak 0.11nm spectral modulation were observed. The outputcharacteristics of the SC for different PDF and SMF lengths in the Raman and Brillouin cavity are reported.