A packet switch architecture that can switch optical packets at high throughputs without using any random access memory, without fragmenting variable length packets into fixed length fragments and reassembling them, and without converting the optical packets into electronic packets. Programmable delay lines are use which delay the output of each packet for a programmable amount which may be re-programmed while the packet is being delayed by the programmable delay line. Programmable delay line controllers manages the delays imposed by the programmable delay lines so as to have a look-ahead phase during which information about the packets is gathered and a shift phase during which the sequence of packets is shifted to match an output sequence.