Patent ID: 8200089

Claim:
An optical pulse time spreading apparatus comprising a plurality (s) of optical pulse time spreaders for spreading input optical pulses in time and outputting the optical pulses as a train of chip pulses having a plurality (N) of chip pulses sequentially arranged on a time axis, where N is a parameter of a natural number more than two and s is a parameter of a natural number not exceeding N, wherein with use of a parameter n of a natural number ranging from unity to s, inclusive, each of said n optical pulse time spreaders comprises N phase controllers for controlling phases, said N phase controllers producing a train of chip pulses in which first to N-th chip pulses are arranged on a time axis in sequence, with use of a parameter a of a predetermined real number not less than zero but below unity, the chip pulses being arranged such that a phase difference equal to 2π{a+(n−1)/N} is given between adjacent ones on the time axis of the first to N-th chip pulses, if the parameter N is an odd number, the first to {(½)(N+1)}-th phase controllers being configured to monotonically increase a reflectivity of the optical pulse in numeric order of said phase controllers while the {(½)(N+1)}-th to N-th phase controllers are configured to monotonically decrease the reflectivity of the optical pulse in numeric order of said phase controllers, or if the parameter N is an even number, the first to (N/2)-th phase controllers being configured to monotonically increase the reflectivity of the optical pulse in numeric order of said phase controllers while the {(N/2)+1}-th to N-th phase controllers are configured to monotonically decrease the reflectivity of the optical pulse in numeric order of said phase controllers, the reflectivities of the optical pulse in said (N/2)-th and {(N/2)+1}-th phase controllers being equally defined.