Broadband optical single sideband (OSSB) modulation is obtained based on the double-reflected chirped fiber Bragg grating (DR-CFBG) structure.This is achi eved by launching orthogonally polarized optical double sideband (ODSB) modulation signals in both directions into the CFBG with the help of circulators and polarization controllers,which avoids the crosstalk bet ween the double-reflected signals.An OSSB modulation system based on the fabricated CFBG is set up.This structure filters out optical carrier and one sideband while can cels dispersion,which avoids the phase distortion obtained by filtering.For the transmission over 6km,the proposed scheme is superior to the ODSB modulated 40Gbit/s non-return-to zero (NRZ) signal transmission.When 2.5Gbit/s NRZ data located at different radio frequency (RF) carriers,after 50km transmission dis tance,20GHz RF carrier power penalty is 3dB lower than that of 10GHz RF carri er and 1.2dB lower than that of 40GHz RF carrier.The proposed sturcture extend s transmission distance greatly compared with traditional ODSB modulation.The tr a nsmission performance of the proposed structure can be improved by decreasing FB G fabrication error and increasing the slope of CFBG reflective spectrum edge.