Digital chaotic behavior in an optically processing element is
reported. It is obtained as the result of processing two fixed trains of bits.
The process is performed with an optically programmable logic gate,
previously reported as a possible main block for optical computing. Outputs
for some specific conditions of the circuit are given. Digital chaos is
obtained using a feedback configuration. Period doublings in a
Feigenbaum-like scenario are obtained. A new method to characterize
this type of digital chaos is reported.