Photonics generation of linearly chirped electrical pulse with ultra-wide frequency band up to THz

In this paper, we demonstrate a simple method to generate ultra-wide band linearly chirped electrical pulse based on interfering of a linearly chirped optical pulse and a continuous wave (CW). The linear chirp is firstly imparted on an ultra-short optical pulse by the dispersion compensation fiber (DCF) which has no bandwidth limit compared with methods using fiber Bragg grating (FBG). The center frequency and the bandwidth of the generated linearly chirped electrical pulse are adjustable by tuning the center frequency of the CW light and the bandwidth of the optical band pass filter (OBPF) in front of the DCF. Our method shows the ability to generate linearly chirped electrical pulse with bandwidth up to THz. The influences of the initial phase difference and the power ratio between ultra-short optical pulse and CW on the generated chirped electrical pulse are also discussed.