RESUMO
The secure key generation and distribution (SKGD) are unprecedentedly important for a modern secure communication system. This paper proposes what we believe to be a novel scheme of high-speed key distribution based on interference spectrum-shift keying with signal mutual modulation in commonly driven chaos synchronization. In this scheme, delay line interferometers (DLI) are utilized to generate two low-correlation interference spectra from commonly driven synchronous chaos, and then a 2 × 2 optical switch can effectively change the relationship between the two interference spectra in post-processing by shifting the states of the switch. The signals then undergo electro-optic nonlinear transformation through a hardware module, which includes a signal mutually modulating module (SMMM) and a dispersion component. This optimization significantly enhances the entropy source rate of synchronized chaos from both legitimate users. Moreover, thanks to the introduction of DLIs and electro-optic nonlinear transformation module, the key space of the proposed scheme is remarkably improved. In comparison to traditional chaotic drive-response architectures, the scheme effectively suppresses residual correlation. A 6.7 Gbit/s key distribution rate with a bit error rate below 3.8 × 10-3 is experimentally demonstrated over a 40â km single-mode fiber (SMF).
RESUMO
A multiple-layer thin film of Pt/Ga2O3-x/SiC/Pt-based resistive switching is systematically investigated. Excellent bipolar resistive switching behavior is observed with a high resistance switching ratio of OFF/ON up to 103. The current-voltage relations plot implies the Ohmic conductance of the ON state, while the space and interface charge limited the current of the OFF state. The micro mechanism of resistive switching is explained by the formation/rupture of conductive filaments formed out of oxygen vacancies within the Ga2O3-x and SiC region. In particular, these devices exhibit excellent stability. The high OFF/ON resistance ratio can be completely retained for a number of days without degradation.
RESUMO
Conductive filament mechanism can explain major resistance switching behaviors. The forming/deforming of the filaments define the high/low resistance states. The ratio of high/low resistance depends on the characterization of the filaments. In many oxide systems, the oxygen vacancies are important to forming the conductive filaments for the resistance switching behaviors. As ultrawide band gap semiconductor, Ga2O3 has very high resistance for its high resistance state, while its low resistive state has relative high resistance, which normally results in low ratio of high/low resistance. In this letter, we report a high ratio of high/low resistance by ultraviolet radiation. The I-V characteristics of Au/Ti/ß-Ga2O3/W sandwich structure device shows that the HRS to LRS ratio of 5 orders is achieved.
RESUMO
Multilayer thin films based on the ferromagnetic and ultraviolet transparent semiconductors may be interesting because their magnetic/electronic/photonic properties can be manipulated by the high energy photons. Herein, the Ga2O3/(Ga1-xFex)2O3 multilayer epitaxial thin films were obtained by alternating depositing of wide band gap Ga2O3 layer and Fe ultrathin layer due to inter diffusion between two layers at high temperature using the laser molecular beam epitaxy technique. The multilayer films exhibits a preferred growth orientation of crystal plane, and the crystal lattice expands as Fe replaces Ga site. Fe ions with a mixed valence of Fe(2+) and Fe(3+) are stratified distributed in the film and exhibit obvious agglomerated areas. The multilayer films only show a sharp absorption edge at about 250 nm, indicating a high transparency for ultraviolet light. What's more, the Ga2O3/(Ga1-xFex)2O3 multilayer epitaxial thin films also exhibits room temperature ferromagnetism deriving from the Fe doping Ga2O3.