A Steganography-Based Optical Image Encryption System Using RGB Channel Integration

An optical image encryption system with adaptive steganography using red, green, and blue （RGB） channel integration is proposed. The optical image encryption system employs a double random phase encoding algorithm to encrypt and decrypt color images. The RGB channel in a color image is first integrated into a large grayscale image. Then the integrated image is encrypted by two random phase masks. The secret data is then embedded into the encrypted image with a specific hiding sequence generated by the zero-LSB （least significant bits） sorting technique which is a content-dependent and low distortion data embedding method. Experimental results show that the proposed, method has a good performance in both hiding capacity and decrypted image quality.

The Possibility of Applying Spectral Redundancy in Coherent DWDM Systems for Increasing the Data Transmission Rate and Decreasing Nonlinear Effects and Double Rayleigh Scattering with Great Security of Data

A new method coherent DWDM system has been proposed. Standard method uses 90 wavelengths with channel capacity 100 G, so total capacity amounts to 9 Terabit, optical power is P. New “channel super” (CS) consists of 15 wavelengths, number of CS is 6, so total number of wavelengths is 90 too, total capacity is 6 Terabit, but optical power is 4/15P. Over ULH and EULH markets, standard approach will be forced to reduce the total capacity to 2.4 Terabit with optical power 4/15P as in proposed method. But the new can reach 6 Terabit with the same optical power 4/15P.

All optical wavelength converter and its application in optical network

All optical network （AON） is a hot topic in recent studies of optical fiber communications. Key techniques in AON include optical switching/routing, optical cross connection （OXC）, all optical wavelength conversion （AOWC）, all optical buffering, etc. Opti- cal switching/routing is in fact wavelength switching/ routing. OXC and wavelength conversion （WC） are introduced into cross nodes so that a virtual wavelength path is established. With WC, communication route is formed only if there is unused wavelength in an individual segment link. The rate wavelength usage is thus greatly increased. The blocking rate of network can be reduced by adding WCs, especially for huge capacity multiple nodes ones. Therefore, WC has attracted much attention in basic research of optical communication and is used in some experimental networks.This dissertation studies all optic wavelength conversion and its application, with the contributions in the following five aspects.

Transmission resonance and color generation of metal-dielectric subwavelength gratings in visible regions

Metal-dielectric subwavelength gratings under s-polarized and p-polarized visible radiation are studied for discovering their intriguing behaviors of spectral resonance and color property.The dependence of their resonance and color on grating parameters as well as angle of incidence and position of plane of incidence is also analyzed.For s-polarized light,the behavior of spectral resonance with single peak and higher peak efficiency is found.While transmission spectra for p-polarized light are not able to achieve a behavior like that of s-polarization,creating a perceived color is feasible.Moreover,a security grating with distinctive color shifts has been designed and its resonant properties as well as related color variation have also been provided.

High-resolution 1D moire s as counterfeit security features

A moireis an interference pattern that appears when two different periodic structures are overlaid.The image created is extremely sensitive to small variations in the original layers and is thus very interesting for anti-counterfeit protection.We present a microfabricated 1D moire enabling complex high-resolution patterns as a significantly improved security feature that cannot be reproduced using standard printing methods.Furthermore,we demonstrate,theoretically and experimentally,that a microscopic deviation from the original design results in a macroscopic variation in the moire that is clearly visible to the naked eye.The record resolution achieved in the elements fabricated and the increased design freedom,make these high-resolution moires excellent candidates for a variety of visually appealing security applications.

Research on High Power Inter-Channel Crosstalk Attack in Optical Networks

While all-optical networks become more and more popular as the basis of the next generation Internet(NGI)infrastructure,such networks raise many critical security issues.High power inter-channel crosstalk attack is one of the security issues which have negative effect on information security in optical networks.Optical fiber in optical networks has some nonlinear characteristics,such as self phase modulation(SPM),cross phase modulation(XPM),four-wave mixing(FWM)and stimulated Raman scattering(SRS).They can be used to implement high power inter-channel crosstalk attack by malicious attackers.The mechanism of high power inter-channel crosstalk attack is analyzed.When an attack occurs,attack signal power and fiber nonlinear refractive index are the main factors which affect quality of legitimate signals.The effect of high power inter-channel crosstalk attack on quality of legitimate signals is investigated by building simulation system in VPI software.The results show that interchannel crosstalk caused by high power attack signal leads to quality deterioration of legitimate signals propagated in the same fiber.The higher the power of attack signal is,the greater the fiber nonlinear refractive index is.The closer the channel spacing away from the attack signal is,the more seriously the legitimate signals are affected by attack.We also find that when attack position and power of attack signal are constant,attack signal cannot infinitely spread,while its attack ability shows a fading trend with the extension of propagation distance.

Secure Communication System Based on Chaos in Optical Fibre

1 IntroductionRecently, there have been intense research activities on the study of synchronized chaos generated by fibre lasers and its application to secure communication systems. So far, all studies concentrate on two aspects: (1) the effect of the transmission channel between the transmitter and the receiver has been neglected, and (2) the chaos and the signal are carried by one wavelength. Both theoretical and experimental investigations

Secret key exchange in ultralong lasers by radiofrequency spectrum coding

We propose a new approach to the generation of an alphabet for secret key exchange relying on small variations in the cavity length of an ultralong fiber laser.This new concept is supported by experimental results showing how the radiofrequency spectrum of the laser can be exploited as a carrier to exchange information.The test bench for our proof of principle is a 50-km-long fiber laser linking two users,Alice and Bob,where each user can randomly add an extra 1-km-long segment of fiber.The choice of laser length is driven by two independent random binary values,which makes such length become itself a random variable.The security of key exchange is ensured whenever the two independent random choices lead to the same laser length and,hence,to the same free spectral range.