An all-optical ON-OFF switch is demonstrated using a single-mode Fabry-Perot laser diode. The operation principle of the proposed switch is the gain modulation of injection locked single mode Fabry-Perot laser diode (SM FP-LD) by an external control beam. In this paper, the operation principle is explained and a 10 Gb/s data signal is switched ON and OFF with a control signal of 200 MHz. We measured the switched output with an extinction ratio of 15.4 dB. The rising and falling times of the switch were measured as 90 ps and 80 ps, respectively.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.