A broad-band high-speed linearized swept laser source based on grating/polygon mirror tunable filter is reported. In order to facilitate the filtering system, the tunable filter consists of polygon scanner and grating in Littrow telescope-less configuration. Parallel implementation of two semiconductor optical amplifiers with different wavelength ranges is adopted in the laser resonator for broad-band light amplification. Center wavelength of the developed swept laser source is 1312 nm with a turning range of 170 nm and 3dB bandwidth of 116 nm. A repetition frequency up to 50 kHz with an average output power of 2 mW is realized while the polygon is scanned at a speed of 695 r/s. This high-speed broad-band linearized swept laser source is especially applicable to high resolution swept source based optical coherence tomography, of which the axial resolution can reach to 6.5 μm.