Iterative learning pre-distortion linearization for hybrid integrated frequency-modulated continuous-wave laser source

A pre-distortion linearization of frequency modulation based on thermal tuning by iterative learning is proposed. The update algorithm is related both to the residual frequency error and its first-order differential. A narrow linewidth laser with a repetition rate of 100 Hz, 500 Hz, 1 kHz, and 2.5 kHz is experimentally demonstrated. When a least-squares linear fitting is applied to the averaged laser frequency sweep, the linear regression coefficient 1 − r² is calculated less than 10⁻⁷. The proposed method provides clues for the realization of the linear frequency modulation continuous wave source and has a possibility to achieve given arbitrary frequency modulation waveforms.