The gray code based all-optical analog-to-digital conversion (ADC) using optical interconnection is described. Recent tremendous growths of optical communications and digital signal processing have encouraged the dema...
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(纸本)0819464481
The gray code based all-optical analog-to-digital conversion (ADC) using optical interconnection is described. Recent tremendous growths of optical communications and digital signal processing have encouraged the demand of high-speed and high-resolution ADC. To pursue a high-speed and high-resolution ADC, optical approaches have attracted much attention recently. ADC generally consists of three procedures: sampling, quantization and coding. Whereas the optical sampling techniques have been proposed and realized, the optical quantization and coding techniques have investigated depending on various applications. For the application to the binary detection of a high-speed digital signal, we previously proposed an all-optical ADC which consists of optical quantization using self-frequency shifting in a fiber and optical coding using optical interconnection for general binary code. In addition, since we can easily prepare optical interconnection patterns corresponding to the various codes, this technique can be used in any coding schemes. In this paper, we demonstrate the gray code based all-optical ADC to verify its scalability. Experimental results show that the 8-levels analog signals can be successfully converted into the bitwise allocated 3-bit gray code.
Integration of a proposed all-optical analog-to-digital (A/D) converter is described. To realize a high-speed and high-throughput system, optical A/D conversion has attracted much attention. A/D conversion generally c...
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Integration of a proposed all-optical analog-to-digital (A/D) converter is described. To realize a high-speed and high-throughput system, optical A/D conversion has attracted much attention. A/D conversion generally consists of three processes of sampling, quantization and coding. Whereas an optical sampling technique has already been realized, there have been few investigations on the optical quantization and optical coding technique. We previously proposed an all-optical A/D converter which realizes both optical quantization and optical coding. In this paper, we integrate the proposed all-optical A/D converter to improve its performance and stability. We verify the operation of the integrated all-optical A/D converter composed of a short high nonlinear fiber, arrayed waveguide gratings and variable optical attenuators. (c) 2005 The optical Society of Japan.
Further to the optical coding based on fluorescent semiconductor quantum dots (QDs), a concept of using mixtures of multiple single-color QDs for creating highly secret cryptograms based on their absorption/emission p...
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Further to the optical coding based on fluorescent semiconductor quantum dots (QDs), a concept of using mixtures of multiple single-color QDs for creating highly secret cryptograms based on their absorption/emission properties was demonstrated. The key to readout of the optical codes is a group of excitation lights with the predetermined wavelengths programmed in a secret manner. The cryptograms can be printed on the surfaces of different objects such as valuable documents for security purposes. (C) 2004 optical Society of America.
A new method for developing optical code division multiplexed access (CDMA) address code sequences is presented. The method is based on the genetic algorithm, which has already shown success in developing two-dimensio...
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A new method for developing optical code division multiplexed access (CDMA) address code sequences is presented. The method is based on the genetic algorithm, which has already shown success in developing two-dimensional correlation functions for pattern recognition. The algorithm is very flexible in its optimization criteria and is thus adequate for various optical CDMA applications, including coherent and noncoherent systems. Preliminary computer experimental results are presented that indicate very good discrimination ratios and very fast convergence of the search process. important implications include synchronization-independent CDMA system design, reduction in optical beat noise, optical power budget improvement, and enhanced security. (C) 1999 Society of Photo-optical Instrumentation Engineers. [S0091-3286(99)01901-7].
This letter details an initial experimental demonstration of (de)coding of optical sequences coded in the two-dimensions of phase and wavelength through a pseudolocal oscillator. Narrow pulses at 1 Gb/s originating fr...
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This letter details an initial experimental demonstration of (de)coding of optical sequences coded in the two-dimensions of phase and wavelength through a pseudolocal oscillator. Narrow pulses at 1 Gb/s originating from a super-continuum (SC) fiber source with a specific frequency variation across their temporal width were, in addition, phase coded producing hybrid optical sequences. Successful decoding of the sequences using a pseudolocal oscillator in tandem with a coupler and balanced detector (coherent decoding) was accomplished. This approach to code formation allows access to a larger family of codes, potentially permitting more flexible network implementations based on optical code division principles.
We demonstrate spectral coding in communication systems based on the use of refractive index dispersion of transparent optical materials. This approach to spectral coding is extremely simple and cheap and allows fibre...
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We demonstrate spectral coding in communication systems based on the use of refractive index dispersion of transparent optical materials. This approach to spectral coding is extremely simple and cheap and allows fibre or integrated devices to be realised.
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