Clock acquiring system and method for optical communication system

The invention discloses a time distilling system and method in optical communication system that includes time distilling device and code mixing device. The code mixing device inputs the processed the input optical signal impulse into time distill device. It sets plural delay line between two optical couplers. The delay inequality is the integral multiple of the transferring optical impulse cycle. The method includes the following steps: inputting the optical signal impulse into code mixing device, taking process to the signal impulse, and outputting to time distilling device. The code mixingdevice separates the input optical signal impulse into multiple branches, takes delay to the multiple branches, and superposes and outputs the multiple branches optical signal impulse.