Thanks to the advances of digital signal processing, high-order modulation formats signals with coherent detection provide more spectrally efficient optical transmission systems. Dual polarization (DP) quadrature phase shift keying (QPSK) operating at 100 Gb/s with receiver digital signal processing (DSP) are now commercially available [1]. 16-ary quadrature amplitude modulation (16-QAM), doubling the spectral efficiency (SE) further to 4 bit/s/Hz [2], become the potential candidate for next generation optical transmission system beyond 100Gb/s per channel.
Consequently, extensive researches have been done for 16-QAM signal generation. Several methods have been demonstrated to realize 16-QAM transmitter. 16-QAM signals can be generated serially with binary diving signals by cascading IQ modulator, Mach-Zehnder Modulators (MZM) and phase modulators (PM) [3], or cascading two IQ modulators [4]. Such transmitter composed of several discrete modulators, thus a large insert loss is induced and the long term stability becomes a big issue. Another approach for 16-QAM generation is to integrate several modulators in parallel structure, such as two IQ modulators, or several MZM modulators [5][6]. However, the complex modulator structures make it hard to fabricate. Another practical method to realize 16-QAM transmitter is to use four-level driving signals to drive an commercially-available signal-drive IQ modulator[2][7][8]. In such approach, the four-level driving signals are relatively difficult to generate and processing, comparing to typical binary driving signals. Thus, expensive digital-to-analog converters (DAC) are usually used for four-level signal generation.
In this paper, we propose and experimentally demonstrate a 16-QAM tra...
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...6QAM generation using a new synthesizing method”, ECOC, 2009. pp. 1-2.
[4] G.-W. Lu et al., “40-Gbaud 16-QAM transmitter using tandem IQ modulators with binary driving electronic signals”, OPT EXPRESS 18(22), 23062-23069 (2010).
[5] A. Chiba, et al., “16-level quadrature amplitude modulation by monolithic quad-parallel mach-zehnder optical modulator”, ELECTRON LETT 46(3), 227-228 (2010).
[6] G. W. Lu et al., “16-QAM Transmitter using Monolithically Integrated Quad Mach-Zehnder IQ Modulator”, ECOC, 2010, Paper Mo.1.F.3 2010.
[7] P. J. Winzer et al., “Spectrally efficient long-haul optical networking using 112-Gb/s polarization-multiplexed 16-QAM”, J LIGHTWAVE TECHNOL 28(4), 547–556 (2010).
[8] M. S. Alfiad et al.. “11×times, 224-Gb/s POLMUX-RZ-16QAM Transmission Over 670 km of SSMF With 50-GHz Channel Spacing”, IEEE PHOTONIC TECH L 22(15), 1150-1152( 2010).
BinOptics designs, develops, and manufactures monolithically integrated optoelectronic components based on the proprietary technology developed at Cornell University. It also produces integrated photonic components, which include its lasers. These components can be integrated into indium phosphide and other semiconductor materials, which give BinOptics a competitive advantage. This unique platform allows the company to meet commercial requirements with higher reproducibility, more elasticity for product innovation, considerably lower costs, and higher performance than alternative processes. BinOptics’ products address high growth datacom applications, parallel optical interconnects, PON and CWDM (Coarse Wave Division Multiplexing), as well as advanced non-telecom applications. Its products are sold to technology companies in the tele-communications and data-communications industry. BinOptics does not disclose its customer list but two of its customers are Agilent Technologies and Cisco Systems.
“G.726: 40, 32, 24, 16 kbit/s Adaptive Differential Pulse Code Modulation (ADPCM)”, International Telecommunication Union, 1991.
.... A. (2012). LTE, LTE-advanced, and WiMAX: Towards IMT-advanced networks. Chichester, West Sussex, U.K: Wiley.
Introduction: With the advancement in technologies, concentrating on transceivers is increasing. Transceivers operate at various frequencies. The author uses Wilkinson power divider (using three section transmission line transformer) which operates at three different arbitrary frequencies simultaneously to generate the required specifications. This condition of using three different frequencies on contrary to using dual frequencies makes this /or made this paper publishable. This circuit operates in the frequency range 900 MHz - 2.3 GHz.
The uses of Digital Signal Processing in communications has become so large scale that nearly any form of analog communication is considered obsolete. Today, nearly any form of communication used, aside from verbal communication, relates to Digital Signal Processing. Some of the more prominent uses for DSP in communications are; local area networks, cell pho...
Issam, S., A. Khater, A. Bellaouar and M. I. Elmasry, 1996, ―Circuit tech-niques for CMOS lowpower high performance multipliers‖, IEEE Journal of Solid-State Circuits, 31, 1535-1546.
As SAN technology develops, it is growing beyond the use of any one kind of technology. A SAN can be configured to use a number of protocols such as IP or Fibre Channel over a network medium like Ethernet or ATM. FC over Ethernet supports up to 1.06 Mbps. Emerging standards that are still being defined include Gigabyte System Network(GSN) which promises full-duplex 6.4 Mbps over a 40 meter copper cable.
Keywords: Frequency Hopped Multiple Access, Time Division Code Division Multiple Access, Time Division Frequency Hopping, Space Division Multiple Access
All forms of commerce will benefit from fibre optic connectivity as it will lower the cost of communication, which is a vital part of any business. New opportunity for the growth of the data market will emerge as cheaper bandwidth should translate to more users.
[2] A. Shatnawi, A. Abu-El-Haija, A. Elabdalla, “A Digital Receiver for Dual-Tone Multi-frequency (DTMF) Signals”, Technology Conference, Ottawa, CA, May 1997.
The presented transmitter is part of a fully-compliant EDGE SoC and successfully overcomes these challenges at low cost. It is the first to successfully demonstrate a truly fully-digital implementation for the amplitude modulation (AM) path that meets the strict far-out spectral mask limits without requiring an external SAW filter. The all-digital AM path complements the previously reported all-digital phase-modulation (PM) path in a GSM transmitter [1, 2]. The small-signal digital power amplifier (DPA), which realizes the digital modulation of the carrier’s envelope in the polar transmitter, incorporates a sigma-delta dithering module to enhance its digital-to-analog conversion resolution well beyond the 1024-level offered by its segmented thermometer transistor array. Sophisticated signal processing and filtering are applied to ensure that the noise is shaped such that it meets the strict requirements of the reception (RX) band. Inevitable impairments in the amplitude modulation circuitry, resulting ...
...Vardalas, "Pulse Code Modulation: It all Started 75 Years Ago with Alec Reeves," IEEE, June 2012. [Online]. Available: http://www.todaysengineer.org/2012/Jun/history.asp. [Accessed 14 November 2013].
Abstract- Photonic semiconductor is deeply integrated in electronic circuit designs and widely used in many sorts of applications, they act as electrical to optical or optical to electrical transducers.
The concept of fiber optics is simple, yet it provides so many potentialities in the world of technology. Presently the world relies on fiber optical technology for its data and communications systems. The consumer can converse on the telephone and hear voices with clarity, as well as send and receive information on the Internet with ease. However, there still lay a sea of possibilities in this area of technology that has not yet been discovered.
Fiber optics is a new technology that uses rays of light instead of electricity to transmit information over optical fibers at very high speeds. The optical fibers are usually thin strands of glass that are combined into cables and used to send information and computer data in the form of pulses of light. The optical fibers provide much clearer transmission than conventional copper cable and satellite links. The world market for optical fiber continues to grow rapidly, with shipments increasing 14 percent from an estimated 7.0 million kilometers of fiber in 1990 to approximately 8.0 million in 1991. The demand for multimode fiber is predicted to continue to expand through the mid-1990s, with some market analysts indicating that 15 to 20 percent annual growth over the next three years is reasonable. Strong demand is expected for singlemode and multimode fiber to be used in cables for local area networks, telecommunications, cable television (CATV), and transoceanic fiber-optic systems.