US Patent 7983561 Optical pulse time spreading device

An optical pulse time spreading device includes S optical pulse time spreading elements that spread input optical pulses into trains of (N×j) chip pulses, where j is an integer greater than zero, S is an integer greater than one, and N is an integer equal to or greater than S. In the chip pulse trains output by the n-th optical pulse time spreading element (n=1, 2, . . . , S), the light in successive chip pulses is shifted in phase by successive integer multiples of the quantity 2π{a+(n−1)/N}, where a is an arbitrary constant (0≦a<1). In an optical code-division multiplexing system, this optical pulse time spreading device produces an autocorrelation wave with a high energy and a high signal-to-noise ratio.