Tomer Yeminy

Spectral and temporal stealthy fiber-optic communication using sampling and phase encoding

We propose a method for covert fiber-optic communication in both frequency and time domains. The power spectral density of the pulse sequence bearing the information is spread in the frequency domain below the noise level by means of sampling. In addition, temporal phase encryption prevents the coherent addition of the various pulses in the frequency domain, further reducing the signal power spectral density. Thus, there is no need to transmit the signal within the bandwidth of a public user in order to spectrally conceal the signal. Temporal spreading of the pulse sequence is achieved by spectral phase encoding, resulting in a stealthy temporal and spectral transmission.

Analysis of photonic noise generated due to Kerr nonlinearity in silicon ring resonators

The Kerr effect in silicon ring resonators (RRs) is widely used for switching and regeneration of optical communications signals. In addition, it has been shown to considerably limit the performance of refractive index sensors based on high quality-factor RRs. While the Kerr effects impact on output signals of silicon RRs is well known, its influence on the properties of the output noise is yet to be explored. In this work, we analytically and numerically analyze the noise properties of Kerr effect in silicon RRs. We show that the input power, RRs bandwidth, and input optical signal to noise ratio (OSNR) have significant influence on the power and distribution of the output noise. We use the developed noise model to evaluate the RRs noise figure and output noise distribution for optical communications and sensing applications. These noise properties can be used for the design and performance evaluation of optical communications systems and sensors using silicon photonic RRs.

Optical Cryptography for Cyber Secured and Stealthy Fiber-Optic Communication Transmission

We propose a method for stealthy, covert, fiber-optic communication. In this method, the power of the transmitted signal is spread and lowered below the noise level both in time as well as in frequency domains which makes the signal “invisible”. The method is also efficient in jamming avoidance.

All-Optical Silicon-Photonic Constellation Conversion of Amplitude–Phase Modulation Formats

Optical communication networks use electrical constellation converters requiring optical-electrical-optical conversions and expensive symbol-rate limiting electronics. In this paper, a generic method for all-optical silicon-photonic conversion of amplitude-phase modulation formats is proposed. The method is based on the implementation of single-layer radial basis function neural networks. A mathematical model is developed, and the parameters influencing the performance of the method are analyzed. Full optical simulation of a four-symbol constellation conversion was performed, resulting in error-free converted constellation that has an error vector magnitude lower than 2.5%.

Narrowband information encryption using frequency and phase cipher

In this paper, we propose a method for optical communication encryption, based on multi-sub carriers modulation, reducing the transmitted signal effectively below the noise level. The information reconstruction is possible only if the frequencies of the carriers, the phase distortion, and the sampling frequency at the transmitter are in hand. Sampling the signal before transmission improves the SNR after reconstruction, enabling to transmit a low power signal with a low SNR which results in a stealthy transmission.