ABSTRACT
In this paper, a secure key generation and distribution scheme based on the phase noise of an amplified spontaneous emission source is proposed and experimentally verified. A giant key generator that contains two distribution arms is used to generate a specific beat dependent on the path length difference of the arms. Through the method of balanced subtraction of the local signals, the effect of the intensity noise has been mainly excluded, and the two legal users obtain the consistent differential signal that depended on the phase noise. Experiment results show that the correlation coefficient of the key signals reaches to about 0.89, and the bit generation rate of the scheme achieves to 3.06 Gbit/s under a length of 20 km standard single-mode optical fiber route, as the bit error rate stays under 0.02%. Moreover, the converted digital key stream has passed the NIST statistical test suite, which means that the scheme is inherently random in the statistical sense. With the excellent performance mentioned above, the proposed scheme provides a simple and efficient solution for the method of one-time pad.
ABSTRACT
A dual-model hybrid pattern recognition based on a fiber optic line-based sensor with a large amount of data is proposed. The vibration signals are converted to gray-level images to reduce the memory requirement. The ResNet18 model for classification is used. To reduce the false positive rate, the over-zero rate and short-time energy are extracted from the intrusion signal, and a support vector machine (SVM) is used. Finally, a discriminator is constructed to determine the types of events by combining the two models trained on the validation dataset. The results demonstrate the excellent average recognition accuracy of this method, which achieves the 97.1% for six events.
ABSTRACT
A scheme based on bidirectional Michelson interferometers to distribute secret keys through the phase of light wave is proposed and demonstrated. The structure uses two optical cable transmission schemes, lasers of short coherent length, random phase drift, polarization random disturbance, and vibration positioning technology to ensure the safe transmission of the secret key. The feasibility of 80 km secret key transmission is verified by experiments. When the secret key is transmitted at the frequency of 200 kHz, the bit error rate is less than 0.3%, and the disturbance positioning accuracy is within $\pm {100}\;{\rm m}$.
ABSTRACT
We propose a practical secure key generation and distribution (SKGD) scheme for actual application. Based on the experiment results of the polarization properties of the actual optical-fiber link, we propose a SKGD method by the active modulation of the state of polarization of the optical-fiber by two polarization scramblers placed at the local end of the legal users in the point-to-point communication system. Experiment results prove that the signals received by legal users share high correlation using 20 km standard single-mode fiber and 1 KHz polarization scrambling rate, and the bit generation rate can reach to 1216 bit/s with a bit error rate of â¼0.33%. Security of the system is also analyzed in terms of the polarization properties of the system; the theoretical and experimental results indicate that the proposed scheme possesses high security due to the invisibility of the key signal and the technical difficulty of the recovery of the key sequence.
ABSTRACT
A novel distributed fiber-optic sensor is proposed and demonstrated, in which two Mach-Zehnder interferometers are used to detect the interference signals with different wavelengths, and one 3 × 3 coupler is deployed to demodulate the time-varying phase change caused by vibration. The novel dual Mach-Zehnder interferometer (DMZI) is composed of two wavelength division multiplexers. Then, a time delay estimation algorithm is designed to construct two related signals using the phase difference, and the two constructed signals are used to obtain vibration position through cross-correlation. Experimental results show that the sensing distance can reach 100â km and the location error is within ±25 m.
ABSTRACT
A novel distributed fiber-optic localization algorithm with high sensitivity and precision based on merged Michelson-Sagnac interferometer is proposed and demonstrated. By performing simple addition and subtraction processing on the two phase differences of the two interferometers, two superimposed signals with a fixed delay can be obtained. The time delay can be calculated by a cross-correlation algorithm. Combined with the polynomial fitting interpolation, the disturbance location resolution is significantly improved. The total sensing distance can reach 120â km, and the localization errors are within ±35 m and ±160 m in the contact and non-contact disturbance experiment, respectively.
ABSTRACT
We theoretically and experimentally demonstrate a method for measuring the phase and intensity noise and their correlation in superluminescent diodes. A Michelson interferometer containing strongly unbalanced paths has been developed to measure the noise. By the spectral analysis of the photocurrents in detectors, the intensity noise is about twice the value of the phase noise in the superluminescent diode. The more interesting result we obtained is the experimental evidence that the intensity noise and the phase noise are mutually independent. The correlation coefficient of the intensity noise and the phase noise fluctuates between -0.08 and 0, which shows scarcely any sign of amplitude-phase noise correlation. The results offer a basic premise for the analysis of broadband light sources.
