scholarly journals Low Complexity DSP for High Speed Optical Access Networking

2021 ◽  
Vol 11 (8) ◽  
pp. 3406
Author(s):  
Jinlong Wei ◽  
Cedric Lam ◽  
Ji Zhou ◽  
Ivan Aldaya ◽  
Elias Giacoumidis ◽  
...  

A novel low-cost and energy-efficient approach for reaching 40 Gb/s signals is proposed for cost-sensitive optical access networks. Our proposed design is constituted of an innovative low-complex high-performance digital signal processing (DSP) architecture for pulse amplitude modulation (PAM-4), reuses existing commercial cost-effective 10-G components and eliminates the need of a power-hungry radio frequency (RF) component in the transmitter. Using a multi-functional 17-tap reconfigurable adaptive Volterra-based nonlinear equalizer with noise suppression, significant improvement in receiver optical power sensitivity is achieved. Results show that over 30 km of single-mode fiber (SMF) a link power budget of 33 dB is feasible at a bit-error-rate (BER) threshold of 10−3.

2020 ◽  
Vol 10 (17) ◽  
pp. 6106
Author(s):  
Aleksejs Udalcovs ◽  
Toms Salgals ◽  
Lu Zhang ◽  
Xiaodan Pang ◽  
Anders Djupsjöbacka ◽  
...  

While infrastructure providers are expanding their portfolio to offer sustainable solutions for beyond 10 Gbps in the access segment of optical networks, we experimentally compare several modulation format alternatives for future passive optical networks (PONs) aiming to deliver 25+ Gbps net-rates. As promising candidates, we consider the intensity modulation direct detection (IM/DD) schemes such as electrical duobinary (EDB) and 4-level and 8-level pulse amplitude modulations (PAM-4/8). They are more spectrally efficient than the conventional non-return-to-zero on-off-keying (NRZ-OOK) used in current 10G PONs. As we move to higher rates, digital equalization enhances the performance by smoothening the systems imperfection. However, the impact that such equalization has on the optical power budget remains unclear. Therefore, in this article, we fairly compare the optical power budget values of a time division multiplexed PON (TDM-PON) exploiting a linear digital signal equalization at the receiver side. We consider the conventional PON configuration (20 km of single-mode fiber (SMF), 1:N optical power splitting) with IM/DD and net-rates above 25 Gbps. Furthermore, we focus on a downstream transmission imposing the bandwidth limitations of 10G components using a digital filter before the detection. The obtained results show that the use of a digital post-equalization with 43 feed-forward (FF) and 21 feedback (FB) taps can significantly improve the signal quality enabling new alternatives and enhancing the optical power budget.


2021 ◽  
Vol 11 (16) ◽  
pp. 7554
Author(s):  
Isiaka Alimi ◽  
Romil Patel ◽  
Nuno Silva ◽  
Chuanbowen Sun ◽  
Honglin Ji ◽  
...  

This paper reviews recent progress on different high-speed optical short- and medium-reach transmission systems. Furthermore, a comprehensive tutorial on high-performance, low-cost, and advanced optical transceiver (TRx) paradigms is presented. In this context, recent advances in high-performance digital signal processing algorithms and innovative optoelectronic components are extensively discussed. Moreover, based on the growing increase in the dynamic environment and the heterogeneous nature of different applications and services to be supported by the systems, we discuss the reconfigurable and sliceable TRxs that can be employed. The associated technical challenges of various system algorithms are reviewed, and we proffer viable solutions to address them.


2021 ◽  
Vol 11 (9) ◽  
pp. 4284
Author(s):  
Oskars Ozolins ◽  
Xiaodan Pang ◽  
Aleksejs Udalcovs ◽  
Richard Schatz ◽  
Sandis Spolitis ◽  
...  

We experimentally evaluate the high-speed on–off keying (OOK) and four-level pulse amplitude modulation (PAM4) transmitter’s performance in C-band for short-reach optical interconnects. We demonstrate up to 100 Gbaud OOK and PAM4 transmission over a 400 m standard single-mode fiber with a monolithically integrated externally modulated laser (EML) having 100 GHz 3 dB bandwidth with 2 dB ripple. We evaluate its capabilities to enable 800 GbE client-side links based on eight, and even four, optical lanes for optical interconnect applications. We study the equalizer’s complexity when increasing the baud rate of PAM4 signals. Furthermore, we extend our work with numerical simulations showing the required received optical power (ROP) for a certain bit error rate (BER) for the different combinations of the effective number of bits (ENOB) and extinction ratio (ER) at the transmitter. We also show a possibility to achieve around 1 km dispersion uncompensated transmission with a simple decision feedback equalizer (DFE) for a 100 Gbaud OOK, PAM4, and eight-level PAM (PAM8) link having the received power penalty of around 1 dB.


2019 ◽  
Vol 8 (4) ◽  
pp. 11849-11853

FIR (Finite Impulse Response) filters play a significant role in the field of Digital Signal Processing (DSP) to eliminate noise suppression in Electro Cardio Graph (ECG), Imaging devices and the signal stored in analog media. So filter evaluation is accomplished to reduce the noise level. The Filter passes only the desired frequency to pass thereby reducing distortion in the processed signal during measurement. The FIR filter comprises of basic units like adders, multipliers and the delay element for its operations.FIR and IIR are the two types of digital filters chosen based on the range of inputs, complexity and size requirement. Multipliers and adders play a vital role in deterring the performance of FIR filter. In this work, we design and analyze different multiplier and adder for high-performance Fir filter implementation. The Vedic Mathematics is the methods containing 16 Sutras to aid fast mental calculations. In this work, we propose modified Anurupye Vedic multiplier methods with Kogge Stone fast adder for implementation in the direct form FIR filter. This approach provides 1.5% decrease in delay and 10.2% reduced in power, hence increasing speed marginally than previous methods. Along with low power consumption in Very High-Speed Hardware Description Language (VHDL), all the adders and the multiplier topologies are Synthesized using (Xilinx Spartan – 6 FPGA) Trainer Kit and the proposed 8 – Tap FIR filter is executed using this Board


2012 ◽  
Vol 49 (3) ◽  
pp. 243-259 ◽  
Author(s):  
Juvenal Rodríguez-Reséndiz ◽  
Fortino Mendoza-Mondragón ◽  
Roberto A. Gómez-Loenzo ◽  
M. Agustín Martínez-Hernández ◽  
Victor H. Mucino

In this article a methodology for constructing a simple servo loop for motion control applications which is suitable for educational applications is presented. The entire hardware implementation is demonstrated, focusing on a microcontroller-based (μC) servo amplifier and a field programmable gate array-digital signal processor (FPGA-DSP) motion controller. A novel hybrid architecture-based digital stage is featured providing a low-cost servo drive and a high performance controller, which can be used as a basis for an industrial application. Communication between the computer and the controller is exploited in this project in order to perform a simultaneous adaptive servo tuning. The USB protocol has been put into operation in the user front-end because a high speed sampling frequency is required for the PC to acquire position feedback signals. A software interface is developed using educational software, enabling features not only limited to a motion profile but also the supervisory control and data acquisition (SCADA) topology of the system. A classical proportional-integral-derivative controller (PID) is programmed on a DSP in order to ensure a proper tracking of the reference at both low and high speeds in a d.c. motor. Furthermore, certain blocks are embedded on an FPGA. As a result, three of the most important technologies in signal processing are featured, permitting engineering students to understand several concepts covered in theoretical courses.


Author(s):  
Hussain Attia ◽  
Ali Sagafinia

This paper presents an electronic design based on general purpose discrete components for speed control of a single phase induction motor drive. The MOSFETs inverter switching is controlled using Sampled Sinusoidal Pulse Width Modulation (SPWM) techniques with V/F method based on Voltage Controlled Oscillator (VCO). The load power is also controlled by a novel design to produce a suitable SPWM pulse. The proposed electronic system has ability to control the output frequency with flexible setting of lower limit to less than 1 Hz and to higher frequency limits to 55 Hz. Moreover, the proposed controller able to control the value of load voltage to frequency ratio, which plays a major parameter in the function of IM speed control. Furthermore, the designed system is characterized by easy manufacturing and maintenance, high speed response, low cost, and does not need to program steps as compared to other systems based on Microcontroller and digital signal processor (DSP) units. The complete proposed electronic design is made by the software of NI Multisim version 11.0 and all the internal sub-designs are shown in this paper. Simulation results show the effectiveness of electronic design for a promising of a high performance IM PWM drive.


Nanophotonics ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 937-945
Author(s):  
Ruihuan Zhang ◽  
Yu He ◽  
Yong Zhang ◽  
Shaohua An ◽  
Qingming Zhu ◽  
...  

AbstractUltracompact and low-power-consumption optical switches are desired for high-performance telecommunication networks and data centers. Here, we demonstrate an on-chip power-efficient 2 × 2 thermo-optic switch unit by using a suspended photonic crystal nanobeam structure. A submilliwatt switching power of 0.15 mW is obtained with a tuning efficiency of 7.71 nm/mW in a compact footprint of 60 μm × 16 μm. The bandwidth of the switch is properly designed for a four-level pulse amplitude modulation signal with a 124 Gb/s raw data rate. To the best of our knowledge, the proposed switch is the most power-efficient resonator-based thermo-optic switch unit with the highest tuning efficiency and data ever reported.


2021 ◽  
Vol 11 (10) ◽  
pp. 4610
Author(s):  
Simone Berneschi ◽  
Giancarlo C. Righini ◽  
Stefano Pelli

Glasses, in their different forms and compositions, have special properties that are not found in other materials. The combination of transparency and hardness at room temperature, combined with a suitable mechanical strength and excellent chemical durability, makes this material indispensable for many applications in different technological fields (as, for instance, the optical fibres which constitute the physical carrier for high-speed communication networks as well as the transducer for a wide range of high-performance sensors). For its part, ion-exchange from molten salts is a well-established, low-cost technology capable of modifying the chemical-physical properties of glass. The synergy between ion-exchange and glass has always been a happy marriage, from its ancient historical background for the realisation of wonderful artefacts, to the discovery of novel and fascinating solutions for modern technology (e.g., integrated optics). Getting inspiration from some hot topics related to the application context of this technique, the goal of this critical review is to show how ion-exchange in glass, far from being an obsolete process, can still have an important impact in everyday life, both at a merely commercial level as well as at that of frontier research.


Author(s):  
Jifeng Wang ◽  
Qubo Li ◽  
Norbert Mu¨ller

A mechanical and optimal analyses procedure is developed to assess the stresses and deformations of Novel Wound Composite Axial-Impeller under loading conditions particular to centrifuge. This procedure is based on an analytical method and Finite Element Analysis (FEA, commercial software ANSYS) results. A low-cost, light-weight, high-performance, composite turbomachinery impeller from differently designed patterns will be evaluated. Such impellers can economically enable refrigeration plants using water as a refrigerant (R718). To create different complex patterns of impellers, MATLAB is used for creating the geometry of impellers, and CAD software UG is used to build three-dimensional impeller models. Available loading conditions are: radial body force due to high speed rotation about the cylindrical axis and fluid forces on each blade. Two-dimensional plane stress and three-dimensional stress finite element analysis are carried out using ANSYS to validate these analytical mechanical equations. The von Mises stress is investigated, and maximum stress and Tsai-Wu failure criteria are applied for composite material failure, and they generally show good agreement.


MRS Bulletin ◽  
1996 ◽  
Vol 21 (4) ◽  
pp. 38-44 ◽  
Author(s):  
F.K. LeGoues

Recently much interest has been devoted to Si-based heteroepitaxy, and in particular, to the SiGe/Si system. This is mostly for economical reasons: Si-based technology is much more advanced, is widely available, and is cheaper than GaAs-based technology. SiGe opens the door to the exciting (and lucrative) area of Si-based high-performance devices, although optical applications are still limited to GaAs-based technology. Strained SiGe layers form the base of heterojunction bipolar transistors (HBTs), which are currently used in commercial high-speed analogue applications. They promise to be low-cost compared to their GaAs counterparts and give comparable performance in the 2-20-GHz regime. More recently we have started to investigate the use of relaxed SiGe layers, which opens the door to a wider range of application and to the use of SiGe in complementary metal oxide semiconductor (CMOS) devices, which comprise strained Si and SiGe layers. Some recent successes include record-breaking low-temperature electron mobility in modulation-doped layers where the mobility was found to be up to 50 times better than standard Si-based metal-oxide-semiconductor field-effect transistors (MOSFETs). Even more recently, SiGe-basedp-type MOSFETS were built with oscillation frequency of up to 50 GHz, which is a new record, in anyp-type material for the same design rule.


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