D M Geraghty

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A new type of optical encryption based on super-structured Bragg gratings is proposed. Security is provided by the transformation of the signal to noiselike patterns in the optical domain, which hides any structure to nonauthorized users. Encryption at speeds of several gigabits per second with low bit error rates is simulated.
We give a general expression for the polarization dependence of the four-wave mixing (FWM) efficiency in the dual-pump configuration. This expression, along with some general properties of the FWM susceptibility tensor, is used to propose a simple scheme to generate a nearly (1.5-dB variation) polarization independent FWM converted signal. The viability of(More)
We characterize the conversion bandwidth of a four-wave mixing semiconductor optical amplifier wavelength converter. Conversion of 10-Gb/s signals with bit-error-rate (BER) performance of <10/sup -9/ is demonstrated for wavelength down-shifts of up to 18 nm and upshifts of up to 10 nm.
We demonstrate for the first time cascaded wavelength conversion by four-wave mixing in a semiconductor optical amplifier. Bit-error-rate performance of <10/sup -9/ at 10 Gb/s is achieved for two conversions of up to 9 nm down and up in wavelength. For two wavelength conversions of 5 nm down and up, a power penalty of 1.3 dB is measured. A system of two(More)
Optical code-division multiple-access (OCDMA) networks require simple encoders/decoders enabling the integration of optical devices for further development. In this letter, we use silica-on-silicon antisymmetric waveguide Bragg grating devices to demonstrate compact and versatile OCDMA encoder/decoders. These devices use mode conversion to perform(More)
Time-resolved spectral analysis is performed on 10 Gb/s signals wavelength converted by four-wave mixing (FWM) in semiconductor optical amplifiers. A pattern-dependent chirp resulting from parasitic gain modulation by the signal is measured and characterized as a function of the converter's pump-to-probe ratio. This chirp is found to be insignificant for(More)
We design and demonstrate interleaved sampled Bragg gratings with concatenated spectrum which produce high channel counts with simple design and fabrication. These gratings can be applied in multichannel filtering, dispersion compensation, and many other functions. The devices were implemented as reduction-photolithographically written anti-symmetric Bragg(More)
The feasibility of a complete all-optical message encoding, error detection and correction system based in the (7,4) Hamming code is demonstrated. The message encoding and error detector are composed of all-optical logical gates and signal regenerators based on Mach-Zehnder interferometer configurations.