Biblio

Dynamic properties of optical signals in fiber channel provide a unique, random and reciprocal source for physical-layer secure key generation and distribution (SKGD). In this paper, an inherent physical-layer SKGD scheme is proposed and demonstrated, where the random source is originated from the dynamic fluctuation of the instant state of polarization (SOP) of optical signals in fiber. Due to the channel reciprocity, highly-correlated fluctuation of Stokes parameter of SOP is shared between the legal partners, where an error-free key generation rate (KGR) of 196-bit/s is successfully demonstrated over 25-km standard single-mode fiber (SSMF). In addition, an active polarization scrambler is deployed in fiber to increase the KGR, where an error-free KGR of 200-kbit/s is achieved.

Negative curvature hollow core fibers (NC-HCFs) realize great research attention due to their comparatively low losses with simplified design and fabrication simplicity. Recently, revolver type fibers that combine the NC-HCF and conventional lattice structured photonic crystal fiber (PCF) have opened up a new era in communications due to their low loss, power confinement capacity, and multi-bandwidth applications. In this study, we present a customized optical fiber design that comprises the PCF with the NC-HCF to get lowest confinement loss. Extensive numerical simulations are performed and a noteworthy low loss of 4.47×10-05dB/m at a wavelength of 0.85 μm has been recorded for the designed fiber, which is almost 4600 times lower than annular revolver type fibers. In addition, a conspicuous low loss transmission bandwidth ranging from 0.6 μm to 1.8 μm has found in this study. This may have potential applications in spectroscopy, material processing, chemical and bio-molecular sensing, security, and industry applications.

With the traffic growth with different deterministic transport and isolation requirements in radio access networks (RAN), Flexible Ethernet (FlexE) over wavelength division multiplexing (WDM) network is as a candidate for next generation RAN transport, and the security issue in RAN transport is much more obvious, especially the eavesdropping attack in physical layer. Therefore, in this work, we put forward a cross-layer design for security enhancement through leveraging universal Hashing based FlexE data block permutation and multiple parallel fibre transmission for anti-eavesdropping in end-to-end FlexE over WDM network. Different levels of attack ability are considered for measuring the impact on network security and resource utilization. Furthermore, the trade-off problem between efficient resource utilization and guarantee of higher level of security is also explored. Numerical results demonstrate the cross-layer defense strategies are effective to struggle against intruders with different levels of attack ability.

We propose a secure key generation and distribution scheme for data encryption in classical optical fiber channel. A Delay interferometer (DI) is used to track the random phase fluctuation inside fiber, while the reconfigurable lengths of polarization-maintaining (PM) fiber are set as the source of optical phase fluctuations. The output signals from DI are extracted as the secret key and shared between the two-legal transmitter and receiver. Because of the randomness of local environment and the uniqueness of fiber channel, the phase fluctuation between orthogonal polarization modes (OPMs) can be used as secure keys to enhance the level of security in physical layer. Experimentally, we realize the random key generation and distribution over 25-km standard single-mode fiber (SSMF). Moreover, the proposed key generation scheme has the advantages of low cost, compatible with current optical fiber networks and long distance transmission with optical amplifiers.