All-optical method of developing parity generator and checker with polarization encoded light signal

All-optical parallel parity generator circuit with the help of semiconductor optical amplifier (SOA)-assisted Sagnac switches

Communication in today's world is made efficient by digital data transmission. The digital communication employs parity generator at the source and parity checker at destination to ensure an error free transmission. This paper proposes the design of a 3-bit reversible even parity checker and generator using the basic reversible gates. The parity checker and generator circuit is designed using the existing basic reversible gates like Feynman gate, Toffoli gate, Peres gate and New gate and the performance of the designed parity checker and generator is discussed. The proposed design is designed using Modelsim and synthesized using Xilinx Virtex5vlx30tff665-3.

Information and communication technology has continuously driven the demand for higher data transmission rates. At the same time, frequency synchronization technology also needs to continually adapt to the high-precision frequency references required between equipment in high-speed optical communication systems. However, existing time and frequency transmission technologies, which rely on the hardware-timestamp functions specified in IEEE1588, cannot meet the accuracy requirements for Precision Time Protocol (PTP) devices in 5G + or future 6G communications. Multi-core fiber, with its characteristics such as multi-channel transmission, superior symmetry, high integration, and versatility, is poised to become the preferred choice for next-generation communication fibers. There is a need to investigate the co-transmission of RF references and data signals based on multi-core fiber to further expand the capacity of communication data transmission and provide precise RF references for 5G + and future 6G communications. This paper proposes and experimentally demonstrates a novel approach for RF clock references and data signals co-transmission over a seven-core fiber on the same wavelength. By inserting an RF standard tone into the data signal spectrum through spectral modulation, we achieve co-transmission of a 10-MHz RF standard and 224-Gb/s dual-polarization 16-QAM signals over 1 km and 10 km seven-core fiber links based on frequency-synchronous optical network (FSON) architecture. The RF and data signals are received and demultiplexed entirely in the optical domain using a radio frequency and data signal demultiplexing (RFDSD) module. The measured 10-MHz frequency stability over 1 km and 10 km seven-core fiber links is better than commercial rubidium atomic clocks and it demonstrates the potential for picosecond-level clock dissemination within short-reach optical interconnects scenario. This work shows good performance in coherent demultiplexing of 224-Gb/s DP-16QAM signals with all tributaries demultiplexed below the 7% FEC threshold at receiver optical power levels of -19 dBm and − 18.5 dBm for 1 km and 10 km seven-core fiber links, respectively. Our approach provides a promising solution and theoretical foundation for next-generation high-speed, high-capacity, picosecond-level physical delay short-reach coherent optical interconnect applications.

Wavelength Division Multiplexing (WDM) is a key enabling technology for increasing the transmission capacity of optical fiber communication systems. Recently, a new family of optoelectronic devices, including detectors, switches, and emitters, that is based on resonant cavity enhancement, has emerged. Wavelength selective optoelectronic switching is achieved by placing a photothyristor in an asymmetric Fabry-Perot cavity, which provides a highly selective response at a wavelength determined during device fabrication. These WDM optoelectronic devices haue promising applications in optical COmmunications and optical logic circuits. Results on a N-p-n-p optoelectronic switch with a ten wavelength channel capability are presented.

Neuromorphic computing using photonic hardware is a promising route towards ultrafast processing while maintaining low power consumption. Here we present and numerically evaluate a hardware concept for realizing photonic recurrent neural networks and reservoir computing architectures. Our method, called Recurrent Optical Spectrum Slicing Neural Networks (ROSS-NNs), uses simple optical filters placed in a loop, where each filter processes a specific spectral slice of the incoming optical signal. The synaptic weights in our scheme are equivalent to the filters’ central frequencies and bandwidths. Numerical application to high baud rate optical signal equalization (>100 Gbaud) reveals that ROSS-NN extends optical signal transmission reach to > 60 km, more than four times that of two state-of-the-art digital equalizers. Furthermore, ROSS-NN relaxes complexity, requiring less than 100 multiplications/bit in the digital domain, offering tenfold reduction in power consumption with respect to these digital counterparts. ROSS-NNs hold promise for efficient photonic hardware accelerators tailored for processing high-bandwidth (>100 GHz) optical signals in optical communication and high-speed imaging applications.

The Parity Generators and checkers are crucial block in Central Processing Unit especially in the process of Error Detection and correction during data transmission. In this work, the three-bit Quantum Cellular Automata (QCA) even parity generator have been proposed using Layered T AND and OR Gate. The proposed comparator layout needs 9.02% less effective area compared to the best reported design so far. Moreover, the other QCA design metrics such as Effective Area, O-Cost, Cost <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">α</sub> , Irreversible Power Dissipation, and Complexity are analyzed for the proposed Parity Generator circuit. The functionality of the proposed circuit is verified by computer aided design tool QCADesigner.

Machine learning can solve many applications in optical communications, but its benefits are largely validated offline using conventional computers. We will introduce a radically new hardware platform, neuromorphic photonics, for machine learning, and review its applications in different optical communication systems.

This paper concerns an optical millimeter-wave signal generator for fiber-based millimeter-wave systems. The millimeter-wave signal generator is based on two-mode injection locking of a Fabry-Perot (F-P) laser. The millimeter-wave signal can be induced by self-heterodyne detection of the locked two modes in a high-speed photodetector (PD). The locking characteristics of the F-P slave laser and the tunability for the millimeter-wave carrier frequency are demonstrated. When the F-P laser is directly modulated by data signals, the locked two modes are modulated simultaneously. The data signals can then be up-converted to the millimeter-wave band at the PD output. By this direct modulation method, the effect of fiber chromatic dispersion on the millimeter-wave signal components at the PD output can be moderate according to mixing of amplitude and phase modulation on the locked two modes. In virtue of the wide response of the F-P laser, relatively high-speed data (2.5 Gbit/s nonreturn to zero (NRZ)-ASK or 622 Mbit/s NRZ-BPSK) on the millimeter-wave band (52 or 60 GHz) can be transmitted on a 32-km single-mode fiber without bit error. A wide tunable range (56-63 GHz) for the central frequency of the millimeter-wave signals and a wide optical bandwidth (1530-60 nm) of the F-P slave laser are also confirmed by the bit-error measurements of the transmitted data signals.

Optical communications and sensing systems have required optical fibers to meet the demanding applications day by day, such as high bit rates, dense wavelength division multiplexing (DWDM) and long distance, so that there could be always renewed interest in fiber designs to lift fundamental limitations of silica optical fibers. One kind of fiber, which is different from the conventional fiber, is silica photonic crystal fiber (PCF) that has an array of microscopic air-holes running along its length. For PCF, there are two distinct classes as the guidance; one is using a type of total internal refection which is referred to the terms microstructured fiber, holey fiber, effective-index fiber, and hole-assisted fiber, and the other is employing photonic band-gap which is referred to photonic band-gap, Bragg fiber, and omni-directional waveguide. In this paper, we will address recent advances in PCFs. While the potential applications are also addressed, the emphasis will be on PCFs for applications in optical communications and sensing systems.

Optical isolation enables nonreciprocal manipulations of light with broad applications in optical communications. Optical isolation by rotating structures has drawn considerable attention due to its magnetic-free nature and unprecedented performance. Conventional rotation-based optical isolation relies on the use of bulky cavities hindering applications in subwavelength photonics. Here, we propose a mechanism of optical isolation by integrating the unique dispersion of a hyperbolic metamaterial with the transverse spin-orbit interaction of evanescent waves. We show that rotation of a subwavelength hyperbolic nanoparticle breaks the time-reversal symmetry and yields two resonant chiral modes that selectively couple to the transverse spin of waveguide modes. Remarkably, the transverse spin-orbit interaction can give rise to unidirectional coupling and more than $95%$ isolation of infrared light at an experimentally feasible rotation speed. Our work fuses the two important fields of optical isolation and photonic spin-orbit interactions, leading to magnetic-free yet compact nonreciprocal devices for applications in optical communications, chiral quantum optics, and topological photonics.

Tunable optical delay devices have numerous applications in optical communications [1] and have been successfully implemented using slow light elements and fiber or waveguide gratings. There has been considerable interest in siliconon- insulator (SOI) as a technology platform for compact integration of optical signal processing systems. SOI-based delay lines have been realized using coupled ring resonators [2], photonic crystals [3], and various Bragg grating-based configurations including single or coupled chirped sidewall gratings [4,5] as well as tapered rib waveguide gratings [6]. By linearly chirping the period in sidewall gratings, relatively small delays (a few ps) over a bandwidth of tens of nm were demonstrated [4]; with tapered waveguides, significantly larger delays (300-500 ps) were obtained, albeit over a narrower bandwidth (&lt; 2 nm) [6]. On the other hand, some signal processing applications may require large delays (e.g., tens to hundreds of ps) over large bandwidths (several to tens of nm). Several designs have been proposed to meet these requirements, e.g., a step-chirped rib waveguide grating providing 50 ps delay over 15 nm [7] or complementary apodized sidewall gratings providing up to 275 ps over 3 nm [8], however, they have not been realized experimentally. In this paper, we demonstrate discretely tunable optical delay lines that provide tens of ps delay (up to 65 ps) in steps of 15-32 ps over bandwidths of several tens of nm (35-70 nm). The devices are fabricated on SOI using electron beam lithography and implemented through two different approaches: serial sidewall Bragg grating arrays and the step-chirped sidewall Bragg gratings.

Array illuminator based on Talbot effect is an important optical element that has wide applications in optical interconnection, optical communication, and optical computing. This paper summarizes our recent results on this subject. Symmetry of the Talbot effect, that was reported in Optics Communication 115, 40 (1995), is now realized as the first step to revealing other rules for explanation of the Talbot effect for array illumination. The prime-number decomposing rule (Applied Optics 40, 607 (2001)) shows that the number of phase level of a Talbot array illuminator is related with the prime number. Along with the study of the characteristics of the Talbot array illuminator, the applications of the Talbot effect are also in progress. Talbot phase codes are the orthogonal codes that can be used for phase coding of holographic storage. A new optical scanner based on the phase codes for Talbot array illumination has unique advantages over the previous Fresnel encoding method. Furthermore, the hexagonal array illumination based on the Talbot effect was reported in Optics Letters 27, 228 (2002). Recently, a novel two-layered multifunctional computer generated hologram based on the fractional Talbot effect was proposed and implemented (Optics Letters 28, 1513 (2003)), which can be multifunctional for potential use in secure system technology. We believe that the results reported in this paper should be useful tools for further exploration of the Talbot effect and design of novel optical devices that should benefit the practical applications.

This paper outlines low power nano-scale circuit design for even parity generator, as well as, even parity checker circuit using quantum-dot cellular automata (QCA). The proposed even parity generator and even parity checker are achieved by using a new layout of XOR gate. This new XOR gate as a state-of-the-art is much denser and faster than the existing ones. The proposed parity generator has outshined the existing design by reducing the cell count as 10%, area as 5.66%, and latency by 12.5%. The proposed parity checker has also outshined the existing design with an improvement in cell count as 17.94% and in the area as 38.46% having a reduction in latency of 22.22%. The comparison proves that the circuits are denser and faster than the existing one. Nano communication architecture with the proposed circuits also demonstrates the efficiency of this design. Furthermore, the bit-error coverage by the proposed method is described. Besides, the defects in the circuits are explored to facilitate guide to proper implementation. The tests vectors are proposed to identify the defects in the designs and the defect coverage by those test vectors. The estimation of dissipated energy by the layouts establishes a very low energy dissipation nature of the designs. Different parameters like a logic gate, density, and latency are utilized to evaluate the proposed designs that confirm the faster processing speed at nano-scale.

Recent progress in research into two-section laser diodes/amplifiers and their applications in optical communications and photonic switching is reviewed. The laser diodes/amplifiers could be used as optical pulse generators, wavelength-tunable light sources, bistable devices, optical wavelength filters, detectors and optical wavelength convertors. Thanks to ongoing work in this area, practical optical functional devices able to fulfil the needs of system designers are closer at hand than ever before.

Higher-order soliton pulse propagation in lutetium aluminium glasses-doped cerium Lu3Al5O12:Ce3+