Non-invasive WDM channel scrambling for secure high data rate optical transmissions

Abstract

This paper proposes a non-invasive optical scrambling technique to secure optical transmissions at high data rates (>10Gb/s). The proposed method belongs to the optical code-division multiple access (OCDMA) technique, using spectral phase encoding, based on overlapping of adjacent scrambled/spread pulses to encrypt transmitted data. In our system, data confidentiality is directly related to scrambled/spread pulse interference, avoiding direct detection by a power detector, in contrast to network access application (OCDMA), where this overlapping should be avoided. Our goal is to secure data transmission without impacting the physical layer, by guaranteeing the optical transparency of the encryption technique with respect to conventional transmission equipments. Therefore, we simulated the system penalty as a function of the transmission distance for a bit error rate (BER) target of 10-9 to estimate the impact of the linear and non-linear transmission effects on our encryption technique. We consider a point-to-point span for mono-channel and multi-channel setups where self-phase modulation (SPM) and cross-phase modulation (XPM) become significant. In the last section, we discuss the resilience of our encryption technique to some realistic attack scenarios. The eavesdropper can use the linear optical sampling (LOS) technique, which with coherence conditions on the waveform under test, permits to extract the amplitude and the phase of each spectral compound, enabling, to determinate the phase filter used to encrypt. Determining the necessary time to crack the mask allows us to establish the mask refreshment to guarantee data confidentiality.

All-optical cryptography through spectral amplitude and delay encoding

“…It is interesting to note that, unlike in fiber and other practical optical materials, this dispersion does not vary monotonically with frequency because each spectral slice receives its own delay. It is interesting to note that we performed simulations concerning the technique reported in [13] and found that, as in the case of SAE analyzed here, SPE also leads to OBP. same as those for the results presented in Fig.…”

“…Since the investigated technique relies solely on linear devices and effects, its implementation is much simpler and advantageous in relation to other presented in literature [14][15][16]. Moreover, the use of spectral delay encoding also avoids, to certain extent, the presence of OBP that happens in [13] and constitute another upside for the technique considered here.…”

“…Since they are constant in the whole range of frequencies of the spectral slice, each spectral component of the slice acquires its own phase shift. This is an important difference relative to the SPE techniques used in [13], where a constant phase-shift is experienced by all frequency components of a given spectral slice.…”

Aplicação de Algoritmo Genético para Determinação de Chaves Usadas em Criptografia Óptica Mediante Fatiamento Espectral

“…Contudo, apesar de conceitualmente promissora, o mecanismo de sincronização entre o receptor e o transmissor requerido por essa abordagem ainda não pode ser atendido em redes comerciais. Outros esquemas baseiam-se na implementação de codificação espectral de fase (spectral phase encoding, SPE) [6], codificação espectral de amplitude (spectral amplitude encoding, SAE) [7] e codificação espectral de atraso (spectral delay encoding, SDE) [7][8][9][10]. Essas três estratégias são interessantes por serem aplicadas a canais compatíveis com a tecnologia de multiplexação por divisão em comprimento de onda (wavelength division multiplexing, WDM) e, portanto, em princípio, podem ser usadas em redes comerciais.…”

All-optical narrowband spectral slicing encryption with super-Gaussian filters

“…Therefore, delay encoding depends on information content and randomizes signal encryption [7]. This is an important advantage of the considered technique over others where only deterministic phase and amplitude encoding are considered [9,10].…”