A Fourier-domain mode locking (FDML) swept laser source is reported. The swept laser source is composed of a laser resonator and a power amplification unit. The laser resonator includes gain medium, tunable filter and delay line. Serial implementation of two semiconductor optical amplifiers is adopted in the laser as gain amplification. The tunable filter consists of polygon scanner and grating in Littrow configuration. The tuning speed of the developed swept laser centered at 1290 nm is 14.8 kHz with an average output power of 3 mW. The tuning range is 108 nm with 3 dB bandwidth of 61 nm. Swept laser source is one key element in optical-frequency-domain imaging system, and the development of this FDML swept laser source will promote the development of real time optical-frequency-domain imaging technology.