It is shown that, for stationary signals, by use of a microwave switch
able delay line the number of channels in a multichannel fiber-optic c
orrelator may be simply expanded. By replacing one optical tree with a
n electrical tree and by performing the AND operation with double-gate
metal-oxide semiconductor field-effect transistors, we demonstrate tw
o methods of reducing the cost of a multichannel architecture without
a reduction in speed. Using optical implementation for delays longer t
han 5 ns and microwave implementation for delays shorter than 5 ns, we
obtain 20 points of the correlation function of a 500-MHz signal.