Frequency　swept　laser　sources　have　various　applications,　such　as　LIDAR,　spectroscopy,　sensing.　We　demonstrate　a　1.5-mu　m　frequency-sweepable　single　frequency　fiber　laser　in　this　work.　By　modulating　the　intensity　of　the　pump,　photo-induced　refractive　index　change　occurs　in　the　gain　fiber　and　the　free　spectral　range　of　the　laser　is　improved.　As　a　result,　the　frequency　sweeping　can　be　realized.　The　DBR　structure　is　employed　to　ensure　the　single-frequency　operation.　The　central　wavelength　and　the　maximum　sweeping　range　is　measured　to　be　1550.25nm　and　800MHz,　respectively.　A　repetition　rate　up　to　1kHz　with　an　average　output　power　of　0.6mw　is　realized.