Physical Layer Of Optical Network Research Articles

Jamming of optical network operation in physical layer

The paper presents the existing possibilities of disrupting the operation of optical/optoelectronic telecommunication networks in a physical layer, distinguishing between passive and active attacks. The latter relay on jamming the operation of the optical network, ranging from the deterioration of the quality of service to the complete prevention of transmission. Passive attacks, on the other hand, are aimed at eavesdropping on transmissions. The paper discusses the various types of attacks, which are specific to the physical layer of optical networks, as well as capabilities of detection and prevention them based on the machine learning approach among others. Finally, a realistic scenario of an active attack by using of a clip-on coupler has been examined in the context of a local area optical network. The results confirm a very disruptive impact on the transmission quality if the power of the jamming signal is comparable with the power of useful signal.

Optical transmitter fingerprint construction and identification based on chaotic phase space reconfiguration.

An optical transmitter identification scheme based on optical chaotic phase space reconfiguration for secure communication is proposed to target injection attacks in the physical layer of optical networks. First, a feature fingerprint construction method based on reconfigured phase space of optical chaos is proposed. Then the fingerprint is controlled by the feedback intensity and filtering bandwidth of chaos. The in-phase and quadrature-phase encryption (IQE)/decryption (IQD) ensures the loading of fingerprints and realizes the confidential communication. In the experiment, the recognition rate of three transmitters is up to 99.3%. In the simulation, the recognition rate of five optical transmitters reaches 100% after 600 km transmission. The bit error rate of 25 GBaud QPSK signal after 300 km transmission at 25 dB OSNR is 1.6 × 10-3. Compared with the traditional optical transmitter identification methods, the fingerprint of this scheme is controllable. The IQE and IQD not only realize the chaotic fingerprint loading but also ensure the secure transmission of the signal avoiding the synchronization and time delay exposure problems in traditional chaotic communication systems. It is robust to device parameters, with low implementation difficulty and low cost. Therefore, this scheme has research and application value for secure communication in the physical layer of optical networks.

Machine Learning-Assisted Watermarking via Bias Control of Electro-Optical Modulator

We propose an optical watermarking strategy based on precise bias tuning of an electro-optical modulator and a convolutional neural network-enabled decoder. This scheme can be used for identity authentication at the physical layer of optical networks. This method is demonstrated with a transmission demo of about 250 kbit/s watermarking data in a 10-Gbit/s public 20-km communication. The watermarking data is modulated on the bias states of the modulator based on the precise and stable bias control technique. The watermark embedding has been verified to make almost no impact on the 20-km public transmission. For the legal receiver, the invisible watermark data can be extracted with the aid of the convolutional neural network-enabled decoder to verify the legality of the received data. Only one optical source is needed in the proposed scheme and the watermarking is integrated into the public signal naturally. We analyzed and verified the influence of watermarking data on the bit error rate and the channel capacity of the public data. The privacy and security of watermarking data are also analyzed.

Electro-optical chaotic communication system based on additional chaotic phase-shift with time-delay signature concealment

We propose and demonstrate an electro-optical chaotic communication system with additional chaotic phase-shift based on the mutual coupling structure. Under the condition of complete concealment of time-delayed signatures (TDSs), the key space of the system is greatly enhanced and highly reliable chaotic communication is finally realized. The additional-phase introduced by the new branch is nonlinearly superimposed on the phase generated by the chaotic signal of the original branch, which improves the complexity and aperiodicity of chaos. For security performance, the system only needs a very small feedback gain (i.e., βi = 2.5) to conceal TDSs. Moreover, since the system has only one chaotic signal transmitted in the transmission link, it overcomes the exposure of TDSs caused by the cross-correlation characteristics between different links. At the same time, the system has strong synchronization robustness and can achieve high-quality communication when the parameters are well-matched. To sum up, the proposed system can effectively resist eavesdropping, which provides security for the physical layer of optical networks.

Linearized Bregman Iterations for Automatic Optical Fiber Fault Analysis

Supervision of the physical layer of optical networks is an extremely relevant subject. To detect fiber faults, single-ended solutions such as the Optical Time Domain Reflectometer (OTDR) allow for precise measurements of fault profiles. Combining the OTDR with a signal processing approach for high-dimensional sparse parameter estimation allows for automated and reliable results in reduced time. In this work, a measurement system composed of a Photon-Counting OTDR data acquisition unit and a processing unit based on a Linearized Bregman Iterations algorithm for automatic fault finding is proposed. An in-depth comparative study of the proposed algorithm's fault-finding prowess in the presence of noise is presented. Characteristics such as sensitivity, specificity, processing time, and complexity, are analysed in simulated environments. Real-life measurements that are conducted using the Photon-Counting OTDR subsystem for data acquisition and the Linearized Bregman-based processing unit for automated data analysis demonstrated accurate results. It is concluded that the proposed measurement system is particularly well suited to the task of fault finding. The natural characteristic of the algorithm fosters embedding the solution in digital hardware, allowing for reduced costs and processing time.

Experimental Validation of Time-Synchronized Operations for Software-Defined Elastic Optical Networks

Elastic optical networking (EON) has been proposed as a solution to efficiently exploit the spectrum resources in the physical layer of optical networks. Moreover, by centralizing legacy generalized multiprotocol label switching control-plane functionalities and providing a global network view, software-defined networking (SDN) enables advanced network programmability valuable to control and configure the technological breakthroughs of EON. In this paper, we review our recent proposal [Optical Fiber Communication Conf., 2017, paper W4J.6] of time-synchronized operations (TSO) to minimize disruption time during lightpath reassignment in EON. TSO has been recently standardized in SDN, and here we discuss its implementation using NETCONF and OpenFlow in optical networks. Subsequently, we update our analytical model considering an experimental characterization of the WSS operation time. Then, we extend our previous work with an experimental validation of TSO for lightpath reassignment in a five-node metropolitan optical network test-bed. Results validate the convenience of our TSO-based approach against a traditional asynchronous technique given its reduction of disruption time, while both techniques maintain a similar network performance in terms of optical signal-to-noise ratio and optical power budget.

Physical Layer Security Solutions for High Speed Data Networks

To improve the confidentiality and availability of the network, it is important to provide multilevel security in the physical layer of optical networks. Based on the orthogonal characterization of OFDM, we introduce a new electronic encryption method for the encryption of the subcarriers symbols after data mapping. Since all-optical networks are emerging as implementations for very high data rate communications, flexible switching and broadband application support, we present a novel all-optical security system technique using random sequence encryption. The noise function was applied via a pseudo-random noise generator seeded with an encryption key. We analyze the performance of both security systems under different application circumstances. Our results confirm the effectiveness of the security technique to make the system less vulnerable to attack.

Optical Layer Security in Fiber-Optic Networks

The physical layer of an optical network is vulnerable to a variety of attacks, including jamming, physical infrastructure attacks, eavesdropping, and interception. As the demand for network capacity grows dramatically, the issue of securing the physical layer of optical network cannot be overlooked. In this survey paper, we discuss the security threats in an optical network as well as present several existing optical techniques to improve the security. In the first part of this paper, we discuss various types of security threats that could appear in the optical layer of an optical network, including jamming, physical infrastructure attacks, eavesdropping, and interception. Intensive research has focused on improving optical network security, in the above specific areas. Real-time processing of the optical signal is essential in order to integrate security functionality at the physical layer while not undermining the true value of optical communications, which is its speed. Optical layer security benefits from the unique properties of optical processing-instantaneous response, broadband operation, electromagnetic immunity, compactness, and low latency. In the second part of this paper, various defenses against the security threats outlined in this paper are discussed, including optical encryption, optical code-division multiple access (CDMA) confidentiality, self-healing survivable optical rings, anti-jamming, and optical steganography.