AbstractFull photonic packet switching fabrics require memories, which are not available today in the optical domain: therefore, an alternative is the use of optical buffers based on fibers used as delay lines. This letter reports the optimised implementation of such a buffer operated in a multi‐wavelength regime and accessed by fast optical gates. The buffer operating principles and two different implementation structures are first briefly presented. Then differential delays and influence on bit error rate performance are discussed on the basis of test results within a 4 × 4 photonic packet switching matrix handling ATM cells at 2.488 Gbit/s. The results demonstrate that fiber delay lines are a simple, potentially cost‐effective solution to implement buffering within highspeed photonic packet switching systems, adopting current optical techno