Wavelength-Tunable Monolithically Integrated Chaotic Semiconductor Laser

Chaos wavelength division multiplexing is a key technology to solve incompatibility between chaos secure communication and large capacity fiber data transmission. However, the existing integrated chaotic semiconductor laser can not achieve wavelength tuning in a large range. Here, a wavelength-tunable chaotic semiconductor laser chip has been designed and fabricated. The chip consists of a gain section, a distributed Bragg reflector (DBR) grating section, a semiconductor optical amplifier (SOA) section, and a phase section. With the optical feedback from the reflective facet of the phase section, and the mode-beating of composite cavities, the chip emits chaotic laser. By adjusting the current of DBR grating, the wavelength can be tuned in a range of 13.4 nm, and the central wavelength can be fine-tuned by adjusting the current of the phase region. Moreover, the evolution from periodic oscillation to chaotic oscillation is presented with the variation of the SOA current. The distribution of dynamics and the variation of bandwidth induced by the SOA current and the gain current are investigated. This work explores a wavelength-tunable chaotic semiconductor laser for the wavelength division multiplexing in the application of large capacity chaotic secure optical communications.