PURPOSE: To provide a light cyclic shift register composed entirely of optical elements. CONSTITUTION: This all light beam type feedback shift register consists of an encoding means 301 which make good use of all light interaction, a 1st delay means 302 which connects an encoded clock signal from the output means of an encoding means to a 1st control means of the encoding means a 1st specific time interval later, and a 2nd delay means 303 which connects the encoded clock signal to a 2nd control means of the encoding means a 2nd specific time interval later, the encoding means consists of a means PWR which receives a light clock signal, a control means I1 which receives the 1st delay version of the encoded light clock signal, a control means 12 which receives the 2nd delay version of the encoded light clock signal, and a means OUT2 which outputs the encoded light clock signal, and the encoding means is so featured that the received clock signal is encoded with a value extracted from an exclusive OR circuit for the 1st and 2nd delay encoded clock signals and 3rd delay from the control means to the output means is as long as a specific time interval.
TOTAL OPTICAL-RAY TYPE FEEDBACK REGISTER