We study the wavelength-division multiplexing implementation of the recently proposed temporal Fresnel transform encoding technique, in order to evaluate its potential application for secure data transmission in short-haul fiber optic links. The different signal broadenings produced by each stage of the encoding process are analyzed in a dual time-frequency domain by using the Wigner distribution function. Furthermore, the robustness of the proposed method is illustrated by comparing the signal-to-noise ratio between the input and the decrypted signals obtained by varying typical parameters of the encryption-decryption setup. Numerical simulations revealed good system performance. Finally, we consider experimental feasibility with current photonic technology.
We study the wavelength-division multiplexing implementation of the recently proposed temporal Fresnel transform encoding technique, in order to evaluate its potential application for secure data transmission in short-haul fiber optic links. The different signal broadenings produced by each stage of the encoding process are analyzed in a dual time-frequency domain by using the Wigner distribution function. Furthermore, the robustness of the proposed method is illustrated by comparing the signal-to-noise ratio between the input and the decrypted signals obtained by varying typical parameters of the encryption-decryption setup. Numerical simulations revealed good system performance. Finally, we consider experimental feasibility with current photonic technology.
We analyze the dual random phase encoding technique in the temporal domain to evaluate its potential application for secure data transmission in fiber optic links. To take into account the optical fiber multiplexing capabilities, the noise content of the signal is restricted when multiple channels are transmitted over a single fiber optic link. We also discuss some mechanisms for producing encoded time-limited as well as bandwidth-limited signals and a comparison with another recently proposed technique is made. Numerical simulations have been carried out to analyze the system performance. The results indicate that this multiplexing encryption method could be a good alternative compared with other well-established methods.
Wavelength Division Multiplexing (WDM) is a photonic technology capable to transport over a single fiber more than a Tbit/s aggregate traffic. Currently, WDM is the only deployed method in transcontinental and transoceanic applications. In the optical network, each fiber link consists of segments, each several kilometers long, the connecting points of which are amenable to tapping. When a small amount of optical signal is extracted from a tap, when the signal is properly amplified it can be monitored by unauthorized personnel thus threatening communications and land-security. Since each WDM channel carries traffic from one customer, it is not difficult for the connoisseur to demultiplex a specific channel, isolate a specific payload and break the encrypted datagram. Therefore, in addition to data encryption, high-speed communications security should also rely on securing the optical links. In this paper, we present a WDM link security method that, even if fiber is tapped, constitutes channel monitoring and information decrypting by an eavesdropper or unauthorized personnel virtually impossible. In addition, we describe the circuit building blocks behind the method that makes eavesdropping impossible.
The optical network supporting emerging bandwidth-intensive services has become the cornerstone of the 5G era. However, the development of optical fiber eavesdropping and quantum computing has brought huge security challenges to traditional cryptography. As an effective approach to improving optical layer transmission security, all-optical logic gate encryption has important research significance. This paper proposes a high-speed coherent optical encryption and decryption system based on phase encoding with all-optical logic gates. The system ingeniously designs the phase encoding and decoding scheme between two quadrature phase-shift keying (QPSK) signals, which doubles the encryption and decryption efficiency. In addition, the integration of physical-layer key distribution (PLKD) and physical-layer encryption (PLE) contributes to a reduction in overall system complexity. By adopting real-time signal processing in an all-optical domain, the single-wavelength rate of system security communication can reach 100 Gbps. The system is also applicable to other phase-modulated signals and provides a feasible scheme to enhance transmission security in wavelength division multiplexing (WDM) optical networks featuring high speed, low latency, and high flexibility.
We demonstrate high-rate randomized data-encryption through optical fibers using the inherent quantum-measurement noise of coherent states of light. Specifically, we demonstrate 650Mbit∕s data encryption through a 10Gbit∕s data-bearing, in-line amplified 200-km-long line. In our protocol, legitimate users (who share a short secret key) communicate using an M-ry signal set while an attacker (who does not share the secret key) is forced to contend with the fundamental and irreducible quantum-measurement noise of coherent states. Implementations of our protocol using both polarization-encoded signal sets as well as polarization-insensitive phase-keyed signal sets are experimentally and theoretically evaluated. Different from the performance criteria for the cryptographic objective of key generation (quantum key-generation), one possible set of performance criteria for the cryptographic objective of data encryption is established and carefully considered.
Protecting the security of optical network is a major worldwide challenge. The conventional schemes for securing communications are based on cryptography at the MAC layer and its higher layers, which are facing a great threat with the development of quantum computers. Optical encryption is a promising way for building security on the physical layer of optical communications. In this work, we propose a novel optical encryption scheme for wavelength division multiplexing (WDM) fiber-optic communication systems, by utilizing the private chaotic phase scrambling. Secure transmission of 50 Gbps signal over 50-km standard single-mode fiber is experimentally and numerically demonstrated. The results show that the WDM signal is efficiently encrypted into a noise-like signal, due to the spectral broadening effect of chaotic phase scrambling. Since the processes of encryption and decryption are totally implemented in the optical domain, the proposed scheme can encrypt the entire network traffic with low latency and high speed. Moreover, the proposed encryption scheme is compatible with the existing WDM optical networks, and only one pair of encryption and decryption devices is sufficient to encrypt all WDM channels, thus the scheme can be easily implemented at low hardware cost.
In telecommunication networks and in computer grid networks, a significant ongoing research is in a technology known as wavelength division multiplexing (WDM), which is capable to transport more than 1 Tbps aggregate traffic over a single fiber. However, when massive amounts of information are transported, as in optical networks, there are three issues that stand, cost-efficient ultra-high bandwidth delivery, security of information and data, and security of the network and of the transporting link layer. In optical networks, each fiber link consists of segments, each several kilometers long. Since a single WDM channel carries traffic, there are opportunities for sophisticated eavesdroppers to tap the fiber, copy a channel, isolate a specific payload and attempt to decrypt it if the encryption key is known or it is breakable with a fast computer. Therefore, end-to-end data security should not only rely on the client's encryption method but also on securing the transmission method on the optical link. In this paper, we present a WDM link security methodology that encrypts multiple channels and with multiple keys to render channel monitoring by eavesdroppers virtually impossible. Although our paper presents the applicability of the method on a point-to-point topology, it is applicable to a multilink and edge-to-edge network path.