The chaotic dynamics of a DFB laser are studied ex-5 perimentally under a combination of short and long feedbacks. 6 Chaos bandwidth enhancement is demonstrated using a hybrid 7 III-V/Si DFB laser with a large relaxation oscillation frequency 8 (ROF) of 14 GHz. The impact of short feedback on the ROF is Q1 9 studied and an increase of 2 GHz is observed. Under long feed-10 back, the route to chaos of the device and its dependence on the 11 short feedback dynamics are studied. The short feedback allows 12 tuning the chaotic dynamics obtained under long feedback, and the 13 increase of the ROF translates into an enhancement of the chaos 14 bandwidth to above 16 GHz. This configuration can allow gener-15 ation of wideband chaos using a single laser source in a photonic 16 integrated circuit. 17 Index Terms-III-V materials, nonlinear dynamics, optical feed-18 back, silicon photonics, secure communications. 19 I. INTRODUCTION 20 S ILICON photonics offer tight integration of a variety of 21 active and passive optical and electrical components, and 22 gained so much interest in the last decade that it is now con-23 sidered one of the most promising technology for optical appli-24 cations [1], [2]. Building on the mature fabrication techniques 25 first developed for microelectronics allows creating photonic 26 integrated circuits (PICs) with a high density of optical compo-27 nents, in high volumes and at low costs. Academic and industrial 28 efforts led to the development of novel technical solutions for 29 a variety of domains including sensing, measurement instru-30 mentation, optical signal processing and telecommunications 31