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Huang J.-F.,Institute of Computer and Communications Engineering | Meng S.-H.,Institute of Computer and Communications Engineering | Lin Y.-C.,National Quemoy University | Huang A.-C.,National Cheng Kung University
Proceedings of ICP 2014 - 5th International Conference on Photonics 2014 | Year: 2015

To combat with multiple-users interference and malicious eavesdropping, this talk presents a double signatures scrambling scheme over wavelength/time for a cryptographic optical code-division multiple-Access (OCDMA) network data transmissions. Optical switches and fiber delay lines are placed with arrayed-waveguide grating (AWG) coder/decoders (codecs) to realize wavelength-spreading and time-hopping. On the transmitter side, user data bits are sliced into spectral chips, coded into pseudo-noise (PN) signature codes, and conducted with different PN-code units of time-delay. In the receiver side, complementary delay lines first reverse the summed spectral chips back into the same time basis, then optical switches follow the associated signatures to turn on-off spectral chips into balanced detector for the final data decoding. By changing signature codes frequently, the eavesdroppers cannot catch on the changing code speed and have little chance to detect the channel waveform to solve the code. With such wavelength/time scrambling scheme, data transmission reliability in OCDMA network can be greatly enhanced. © 2014 IEEE. Source


Huang J.-F.,Institute of Computer and Communications Engineering | Huang J.-F.,National Cheng Kung University | Meng S.-H.,Institute of Computer and Communications Engineering | Meng S.-H.,National Cheng Kung University | And 6 more authors.
Procedia Computer Science | Year: 2014

To combat with multiple-users interference and malicious eavesdropping, this paper proposes a double scrambling scheme over time/wavelength for a cryptographic optical CDMA (OCDMA) data transmission. By using wavelength-spreading/time-hopping, data reliability in OCDMA network can be highly improved. On the transmitter side, data bits are sliced into spectral chips, coded into M-sequence codes, and conducted with different units of time-delay. In the receiver side, fiber-delay lines (FDLs) reverse the spectral chips back to the same time basis, and optical switches (OSWs) turn on-off spectral chips into balanced detector for the final data decoding. By changing signature code frequently, the eavesdroppers cannot catch on the changing code speed and have little chance to detect the channel waveform to solve the code. To against eavesdropping, we take advantages of linear cyclic, periodic, and nearly-orthogonal characteristics of M-sequence codes. OSWs and FDLs are added into the arrayed-waveguide grating (AWG) codecs. The spectral codes and the time-delay units will follow cell states of a controlling shift register. Different shift register states will reconfigure AWG light spectra into different coding sequences. After pass through the associated OSWs and FDLs, user signature code appears to be a two-dimensional code matrix. In perspective of eavesdropper, smooth eavesdropping presents difficulties due to signature codes' frequent changing. The system can therefore achieve a high level of network confidentiality. © 2014 Elsevier B.V. Source


Meng S.-H.,Institute of Computer and Communications Engineering | Chen K.-S.,Institute of Computer and Communications Engineering | Huang J.-F.,Institute of Computer and Communications Engineering | Yang C.-C.,Kun Shan University
Canadian Conference on Electrical and Computer Engineering | Year: 2015

In this paper, we construct a composite label sets for optical multi-protocol label switching (MPLS) network. Relatively prime lengths maximal-length (M-sequence) codes are taken to compose into spectral-amplitude coding (SAC) labels. These composite M-labels possess good orthogonality and are compatible with packet labels stacking. With correlation subtraction scheme in packet routing node, local node label can be identified from the stacked labels. The composite M-labels are coded with arrayed-waveguide gratings (AWGs) with small number of input-output ports to reduce hardware requirement. Compared with conventional M-sequence labels, composite M-labels behave more flexibility on routing data packets. The proposed composite M-labels coding can support optical packet switching network (OPS) with fast label processing. © 2015 IEEE. Source


Yen C.-T.,National formosa University | Huang J.-F.,Institute of Computer and Communications Engineering | Chih P.-E.,Institute of Computer and Communications Engineering
Japanese Journal of Applied Physics | Year: 2014

We propose and experimentally demonstrated the two bands optical code-division multiple-access (OCDMA) network over bipolar Walsh-coded liquid-crystal modulators (LCMs) and driven by green light and red light lasers. Achieving system performance depends on the construction of a decoder that implements a true bipolar correlation using only unipolar signals and intensity detection for each band. We took advantage of the phase delay characteristics of LCMs to construct a prototype optical coder/decoder (codec). Matched and unmatched Walsh signature codes were evaluated to detect correlations among multiuser data in the access network. By using LCMs, a red and green laser light source was spectrally encoded and the summed light dots were complementary decoded. Favorable contrast on auto- and cross-correlations indicates that binary information symbols can be properly recovered using a balanced photodetector. © 2014 The Japan Society of Applied Physics. Source


Huang J.-F.,Institute of Computer and Communications Engineering | Nieh T.-C.,Institute of Computer and Communications Engineering | Chen K.-S.,Institute of Computer and Communications Engineering
Optical Engineering | Year: 2013

The cyclic period and free spectral range of arrayed-waveguide gratings (AWG) in a wavelength-division multiplexing/optical code division multiple access optical code division multiple access network are exploited. The total optical network unit (ONU) of network capacity is partitioned into groups of different wavelength in accordance with the geographical location of subscribers based on the radial distance of the ONU to the optical line terminal. Combining concentric circles round by round for ONU groups enables a fixed round-trip time in the data transmission and a significant increase in system performance. Using AWG router, the proposed topology of concentric circles retains signature orthogonality and minimizes wavelength collisions on the photo-detector. Furthermore, the adoption of extended M-sequence codes corresponding to the AWG codec provides a simpler, more efficient coding procedure and accommodates more users in a single group. © 2013 Society of Photo-Optical Instrumentation Engineers (SPIE). Source

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