A sensing system is provided. The sensing system includes an electrical pulse generator that receives first optical pulses output from a pulsed laser, through a first path, and photo-electrically converts the first optical pulses to generate an electrical pulses; and an optical phase detector that receives second optical pulses output from the pulsed laser, through a second path, and outputs an electrical signal that corresponds to a phase error between the electrical pulses and the second optical pulses based on electro-optic sampling.