Using a special property of dynamic complementary-suppression-modulated transmission (DCSMT) in the bacteriorhodopsin (bR) film, we have demonstrated an all-optical time-delay relay. To extend our work, the relationship between the delay time of the all-optical time-delay relay and parameters of a bR film is numerically studied. We show how the delay time changes with the product of concentration and thickness (PCT) of a bR film. Furthermore, the shortest and longest delay times are given for the relay of 'switch off'. The saturable delay time and maximum delay-time of 'switch on' are also given. How the wavelengths (632.8, 568, 533 and 412 nm) and intensities of the illuminating light influence the delay time is also discussed. The simulation results are useful for optimizing the design of all-optical time-delay relays.
