An optoelectronic ultra-wideband RF/wireless communications system is proposed. We refer this new technology as opto-impulse radio. Impulse modulation is a wireless transmission format for multipath and interference environments. It can provide a jam-resistant, high security, low-power RF communications link. Photoconductive (PC) switches are used as front-end elements in wireless impulse communications systems. Direct sequence code division is used to enhance an ultra-wideband impulse modulation communication system. Experimental results show an aggregate processing gain of 44 dB using a 750 MHz spreading bandwidth.