Generation of the non-periodic and delay-signature-free chaotic light

External cavity semiconductor laser (ECSL) is becoming the most common chaotic light source due to its simple and integratable configuration. However, the round trip in feedback cavity with fixed delay makes the chaotic light periodic and reduces complexity. In this paper, we propose and demonstrate experimentally a novel optical feedback scheme to generate non-periodic chaotic light. Unlike the fixed time-delay feedback in ECSL, the proposed method utilizes the backscattering light from a fiber as feedback into semiconductor laser. Such a feedback is a kind of randomly distributed feedback along the fiber, and therefore its 'time-delay' is no longer a fixed value. Our results show that the proposed feedback method can obtain delay-signature-free chaotic light, which is very useful for the security of chaos encryption system and the generation of fast truly random numbers.