High-speed chaotic communication using an optical fibre ring as a key

A chaotic communication scheme with a fibre ring inserted in the optical ~eedback of the transmitter laser as an additional key is proposed under anticipating synchronization. The numerical results show that the key can enhance the communication security effectively. It is theoretically safe for the communication scheme to transmit messages with a frequency beyond the relaxation oscllation frequency.

Integrated sensing and communication in an optical fibre

The integration of high-speed optical communication and distributed sensing could bring intelligent functionalities to ubiquitous optical fibre networks,such as urban structure imaging,ocean seismic detection,and safety monitoring of underground embedded pipelines.This work demonstrates a scheme of integrated sensing and communication in an optical fibre(ISAC-OF)using the same wavelength channel for simultaneous data transmission and distributed vibration sensing.The scheme not only extends the intelligent functionality for optical fibre communication system,but also improves its transmission performance.A periodic linear frequency modulation(LFM)light is generated to act as the optical carrier and sensing probe in PAM4 signal transmission and phase-sensitive optical time-domain reflectometry(Φ-OTDR),respectively.After a 24.5 km fibre transmission,the forward PAM4 signal and the carriercorrespondence Rayleigh backscattering signal are detected and demodulated.Experimental results show that the integrated solution achieves better transmission performance(~1.3 dB improvement)and a larger launching power(7 dB enhancement)at a 56 Gbit/s bit rate compared to a conventional PAM4 signal transmission.Meanwhile,a 4m spatial resolution,4.32-nε/√Hz strain resolution,and over 21 kHz frequency response for the vibration sensing are obtained.The proposed solution offers a new path to further explore the potential of existing or future fibre-optic networks by the convergence of data transmission and status sensing.In addition,such a scheme of using shared spectrum in communication and distributed optical fibre sensing may be used to measure non-linear parameters in coherent optical communications,offering possible benefits for data transmission.

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

A Simple Method to Obtain Exact Soliton Solutions for a Nonlinear Equation in a Loss Fibre System

We show that the nonlinear equation governing wave propagation in a loss fibre system considered byNakkeeran in J. Phys. A34 (2001) 5111 can be brought into the standard nonlinear Schrodinger equation by a simpletransformation.

Suppression of the interactions between fibre gratings used as dispersion compensators in dense wavelength-division multiplexing systems

Chirped fibre Bragg gratings （CFBGs） are required to be concatenated to compensate the fibre dispersion in the dense wavelength-division multiplexing （DWDM） systems. When the channel spacing is small, the performance of CFBGs is degraded, which restricts the usage of fibre gratings. The origin of the interactions between the gratings is analysed and methods of suppressing the interactions are also proposed.

A Simple Method to Obtain Exact Soliton Solutions for a Nonlinear Equation in a Loss Fibre System

We show that the nonlinear equation governing wave propagation in a loss fibre system considered by Nakkeeran in J. Phys. A 34 (2001) 5111 can be brought into the standard nonlinear Schr?dinger equation by a simple transformation.

A polarization stabilizer up to 12.6 krad/s with an additional function of stable state of polarization transformation

This paper reports on an experiment about a novel method of polarization stabilization. The polarization stabilizer proposed here has an additional function of polarization transformation from any state of polarization into any others. The particle swarm optimization is introduced as a control algorithm in the process of either searching or endless tracking. The tracking speed of the stabilizer is obtained up to 12.6 krad/s by using hardware we have in the laboratory, which means that we can achieve a higher speed practical polarization stabilizer if we have faster hardware.