摘要：A new integer linear program(IIP)formulation was developed to solve the problem of shared cyclesdesign for optical networks with and without wavelength *** studies show that theshared cycles design requires much lower redundancy compared with p- cycle design when the maximumnumber of spans allowed in the cycles is relatively small,but the difference in the redundancy betweenthe two designs becomes smaller or disappears as the maximum number of spans allowed in the cycles in-creases.