“…For instance, quadrature phase-shift keying (QPSK) with 2-bit information in one symbol has been extensively used in high-speed optical fiber transmission systems [68,69]. Multilevel modulation format containing multiple constellation points in the constellation diagram can also be used to represent M-ary numbers.…”
The era of cloud computing has fuelled the increasing demand on data centers for highperformance, high-speed data storage and computing. Digital signal processing may find applications in future cloud computing networks containing a large sum of data centers. Addition and subtraction are considered to be fundamental building blocks of digital signal processing which are ubiquitous in microprocessors for arithmetic operations. However, the processing speed is limited by the electronic bottleneck. It might be valuable to implement high-speed arithmetic operations of addition and subtraction in the optical domain. In this chapter, recent results of M-ary optical arithmetic operations for high base numbers are presented. By exploiting degenerate and nondegenerate four-wave mixing (FWM) in highly nonlinear fibers (HNLFs), graphene-assisted optical devices, and silicon waveguide devices, various types of two-/three-input high-speed quaternary/octal/decimal/hexadecimal optical computing operations have been demonstrated. Operation speed up to 50 Gbaud of this computing approach is experimentally examined. The demonstrated M-ary optical computing using high base numbers may facilitate advanced data management and superior network performance.
“…For instance, quadrature phase-shift keying (QPSK) with 2-bit information in one symbol has been extensively used in high-speed optical fiber transmission systems [68,69]. Multilevel modulation format containing multiple constellation points in the constellation diagram can also be used to represent M-ary numbers.…”
The era of cloud computing has fuelled the increasing demand on data centers for highperformance, high-speed data storage and computing. Digital signal processing may find applications in future cloud computing networks containing a large sum of data centers. Addition and subtraction are considered to be fundamental building blocks of digital signal processing which are ubiquitous in microprocessors for arithmetic operations. However, the processing speed is limited by the electronic bottleneck. It might be valuable to implement high-speed arithmetic operations of addition and subtraction in the optical domain. In this chapter, recent results of M-ary optical arithmetic operations for high base numbers are presented. By exploiting degenerate and nondegenerate four-wave mixing (FWM) in highly nonlinear fibers (HNLFs), graphene-assisted optical devices, and silicon waveguide devices, various types of two-/three-input high-speed quaternary/octal/decimal/hexadecimal optical computing operations have been demonstrated. Operation speed up to 50 Gbaud of this computing approach is experimentally examined. The demonstrated M-ary optical computing using high base numbers may facilitate advanced data management and superior network performance.
“…This technique is effective for optical packet switching (OPS) and multi-protocol label switching (MPLS). Improving the performance of LN modulators [6,7] will enable generation of higher-speed, multilevel codes in the future.…”
Abstract:We performed a simulation of optical code generation and processing to determine the number of discriminable codes, which depends on the number of chips and the chip rate. Based on an actual optical binary phase shift keying (BPSK) code generation and processing system, the characteristics of devices in the code generation and processing with threshold processing were considered in this simulation. To handle variable BPSK codes, we used LiNbO 3 (LN) modulators as an optical code generator and a transversal filter (TVF) as an optical code processor. We found that BPSK codes with 2-6 chips, 10, 20, 40 Gchip/s had sufficient threshold margins for code discrimination in the simulation, and this result was in good agreement with experimental results. We performed experiments 4 chip, 10 Gchip/s code generation and processing, and we experimentally confirmed the number of discriminable codes is 8.
“…Single-carrier polarization-multiplexed quadrature phase-shift keying (QPSK) is by now the best-established format for the upcoming 100-Gb/s systems [3]- [5]. Research is now addressing the 400-Gb/s or even 1-Tb/s systems [6], with a large variety of proposed solutions from orthogonal frequency-division multiplexing (OFDM) [7], to subcarrier multiplexing (SCM) [8], from novel modulation formats [9], to classical high-order modulations, like multilevel quadrature amplitude modulations (QAMs) [10], [11].…”
Abstract-Coherent detection has recently allowed the adoption of high-order modulation formats in single-carrier optical systems where a simple feed-forward equalizer, in proper configuration, is able to perfectly compensate for fiber linear impairments, such as group velocity dispersion and polarization-mode dispersion. In this letter, the blind update of the equalizer taps is investigated with reference to a 16-ary quadrature amplitude modulation (QAM) format in the presence of different channel impairments. A novel algorithm is proposed, which represents an improvement of the stop-and-go, through the use of a powerful asynchronous detection strategy.
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