Optical switches based on vanadium dioxide (VO2) thin film have emerged as potential candidates for deployment in future optical transport networks, where switching speed and driving power dissipation will become increasingly important. This paper reviews the basic working principle of optical switch based on VO2 thin film, and gives out the physical thermal model for optical switch based on VO2 thin film, according to which the driving power dissipation and switching speed expressions of the optical switch are obtained in theory. These two the...