Cost‐Effective Transition to 40 Gb/s Line Rate Using the Existing 10 Gb/s‐Based DWDM Infrastructure

In this paper, we propose and demonstrate a cost‐effective technique to upgrade the capacity of dense wavelength division multiplexing (DWDM) networks to a 40 Gb/s line rate using the existing 10 Gb/s‐based infrastructure. To accommodate 40 Gb/s over the link optimized for 10 Gb/s, we propose applying a combination of super‐FEC, carrier‐suppressed return‐to‐zero, and pre‐emphasis to the 40 Gb/s transponder. The transmission of 40 Gb/s DWDM channels over existing 10 Gb/s line‐rate long‐haul DWDM links, including 40×40 Gb/s transmission over KT's standard single‐mode fiber optimized for 10 Gb/s achieves successful results. The proposed upgrading technique allows the Q‐value margin for a 40 Gb/s line rate to be compatible with that of 10 Gb/s.     

Subjective Evaluation of Several Efficient Speech Coders

The voice quality of several 9.6 - 32 kbit/s coders is determined with an extensive set of subjective listening tests. Single encodings of μ255 PCM, adaptive differential PCM (ADPCM), subband coding (SBC), vocoder-driven adaptive transform coding (ATC), adaptive predictive coding (APC), and time domain harmonic scaling combined with SBC are compared in an idealized situation, that is, no added impairments. It is shown that single encodings of modest complexity 32 kbit/s coders such as ADPCM and SBC and more complex 24 kbit/s coders such as vocoder-driven ATC and APC offer quality nearly equivalent to 64 kbit/s μ255 PCM. However, these conclusions are drawn in the absence of a realistic telephone network where tandem encodings, delay limitations, and nonvoice signals exist. Tandem encodings of 64 kbit/s μ255 PCM, 32 kbit/s ADPCM, 16 kbit/s SBC, and 16 kbit/s APC are also evaluated. These 32 kbit/s and 16 kbit/s coders offer degraded tandem performance as compared to 64 kbit/s PCM, with the exception of synchronous tandeming of 32 kbit/s ADPCM with 64 kbit/s PCM where several encodings are subjectively equivalent to a single encoding of 32 kbit/s ADPCM.     

25 Gbit/s无源光网络技术进展和实验研究

高清视频、虚拟现实等新业务的产生以及PON传输5G移动前传和回传信号的需求,要求PON能支持单波超过10 Gbit/s速率的传输.当线路速率超出10 Gbit/s时,色散和功率预算成为限制系统性能的主要因素.介绍了25 Gbit/s PON系统的研究进展和存在的问题,并对采用基于零色散附近的25 Gbit/s速率的EML、分别基于25 Gbit/s和10 Gbit/s速率的APD接收机进行了实验研究.实验结果表明,采用25 Gbit/s速率的APD,EML的发射光功率设置为+5 dBm,在没有光放大器的情况下,可以达到10 Gbit/s对称的吉比特无源光网络的32 dBm的N2级别的光功率预算.     

100Gbit/s技术及应用分析

100Gbit/s已成为目前高速光通信技术的研究焦点。本文分别从发展现状、关键技术、技术应用等方面分别对100Gbit/s进行了分析与探讨,并对100Gbit/s技术的后续发展的展望。     

A 20-Gb/s 0.13-/spl mu/m CMOS serial link transmitter using an LC-PLL to directly drive the output multiplexer

A 20-Gb/s transmitter is implemented in 0.13-/spl mu/m CMOS technology. An on-die 10-GHz LC oscillator phase-locked loop (PLL) creates two sinusoidal 10-GHz complementary clock phases as well as eight 2.5-GHz interleaved feedback divider clock phases. After a 2/sup 20/-1 pseudorandom bit sequence generator (PRBS) creates eight 2.5-Gb/s data streams, the eight 2.5-GHz interleaved clocks 4:1 multiplex the eight 2.5-Gb/s data streams to two 10-Gb/s data streams. 10-GHz analog sample-and-hold circuits retime the two 10-Gb/s data streams to be in phase with the 10-GHz complementary clocks. Two-tap equalization of the 10-Gb/s data streams compensate for bandwidth rolloff of the 10-Gb/s data outputs at the 10-GHz analog latches. A final 20-Gb/s 2:1 output multiplexer, clocked by the complementary 10-GHz clock phases, creates 20-Gb/s data from the two retimed 10-Gb/s data streams. The LC-VCO is integrated with the output multiplexer and analog latches, resonating the load and eliminating the need for clock buffers, reducing power supply induced jitter and static phase mismatch. Power, active die area, and jitter (rms/pk-pk) are 165 mW, 650 /spl mu/m/spl times/350 /spl mu/m, and 2.37 ps/15 ps, respectively.     

40Gb/s DWDM传送技术及实际考虑

给出了40Gb/sDWDM传送系统的进展现状,分析了40Gb/s传输问题和一系列使能技术,讨论了40Gb/sDWDM传送系统基本结构,并从实际应用的角度,对10Gb/s和40Gb/s传输系统的特性及成本进行了比较,最后指出了发展40Gb/s传送系统思路及对策。     

Coherent Optical OFDM Transmission Up to 1 Tb/s per Channel

Coherent optical frequency-division multiplexing (CO-OFDM) is one of the promising pathways toward future ultrahigh capacity transparent optical networks. In this paper, numerical simulation is carried out to investigate the feasibility of 1 Tb/s per channel CO-OFDM transmission. We find that, for 1 Tb/s CO-OFDM signal, the performance difference between single channel and wavelength division multiplexing (WDM) transmission is small. The maximum Q is 13.8 and 13.2 dB respectively for single channel and WDM transmission. We also investigate the CO-OFDM performance on the upgrade of 10-Gb/s to 100-Gb/s based DWDM systems with 50-GHz channel spacing to 100-Gb/s systems. It is shown that due to the high spectral efficiency and resilience to dispersion, for 100-Gb/s CO-OFDM signals, only 1.3 dB Q penalty is observed for 10 GHz laser frequency detuning. A comparison of CO-OFDM system performance under different data rate of 10.7 Gb/s, 42.8 Gb/s, 107 Gb/s and 1.07 Tb/s with and without the impact of dispersion compensation fiber is also presented. We find that the optimum fiber launch power increases almost linearly with the increase of data rate. 7 dB optimum launch power difference is observed between 107 Gb/s and 1.07 Tb/s CO-OFDM systems.      

小波变换音频编码算法研究

任意能量有限信号都可以用紧支撑正交小波基展开或分解，这一点对研究快速高效音频编码算法是非常重要的。本文设计一种基于正交小波变换的高保真音频编码算法，该算法可以把速率为７０５．６ｋｂｉｔ／ｓ的高保真音频信号压缩到１９２ｋｂｉｔ／ｓ，１６０ｋｂｉｔ／ｓ，１２８ｋｂｉｔ／ｓ，９６ｋｂｉｔ／ｓ和６４ｋｂｉｔ／ｓ，并保持重构音频信号的高质量。     

40-Gbit/s TDM transmission technologies based on ultra-high-speedICs

This paper presents 40-Gbit/s time division multiplexing (TDM) transmission technologies based on 0.1-μm-gate-length InP high electron mobility transistor IC's and a scheme for upgrading toward a terabit-per-second capacity system. A 40-Gbit/s, 300-km, in-line transmission experiment and a dispersion-tolerant 40-Gbit/s duobinary transmission experiment are described as 40-Gbit/s single carrier system applications on dispersion-shifted fiber. An ultra-high-speed receiver configuration using a high-output-power photodiode is introduced to realize fully electrical receiver operation beyond 40 Gbit/s. The high-sensitivity operation of the optical receiver (-27.6 dBm@BER=10^-9) is demonstrated at a data bit rate of 50 Gbit/s for the first time using a unitraveling carrier photodiode. A dense wavelength division multiplexing (DWDM) system operating up to terabits per second can be easily realized on a zero-dispersion flattened transmission line using ultra-high speed TDM channels of 40 Gbit/s and beyond. An experiment demonstrates 1.04-Tbit/s DWDM transmission based on 40-Gbit/s TDM channels with high optical spectrum density (0.4 bit/s/Hz) without dispersion compensation     

北电网络TN—6410Gbit／s传输平台与多波长光中继器及其应用

北电网络的新型１０Ｇｂｉｔ／ｓ Ｓ／ＤＭＳ传输节点系统面向宽带传输的需求,可支持１０Ｇｂｉｔ／ｓ群路速率接口和低速１５５Ｍ、６２Ｍ和２．５Ｇｂｉｔ／ｓ等支路端口卡。其多波长光中继器系统（ＭＯＲ／ＭＯＲ＋）采用双向多波长放大器,在单根光纤上支持１６或３２波ＤＷＤＭ传输。二者的结合可使运营商利用现有的光纤,在满足高性能传输及高效率管理的同时,实现最低的每比特每公里传输成本。     

160 Gb/s variable length packet/10 Gb/s-label all-optical label switching with wavelength conversion and unicast/multicast operation

We report on the first demonstration of all-optical label switching (AOLS) with 160 Gb/s variable length packets and 10 Gb/s optical labels. This result demonstrates the transparency of AOLS techniques from previously demonstrated 2.5 Gb/s to this 160 Gb/s demonstration using a common routing and packet lookup framework. Packet forwarding/conversion, optical label erasure/re-write and signal regeneration at 160 Gb/s is achieved using a WDM Raman enhanced all-optical fiber cross-phase modulation wavelength converter. It is also experimentally shown that this technique enables packet unicast and multicast operation at 160 Gb/s. The packet bit-error-rate is measured for all optical label switched 16 /spl times/ 10 Gb/s channels and error free operation is demonstrated after both label swapping and packet forwarding.     

对波分复用系统扩容方式的探索

对在原有8/16×2.5 Gbit/s波分复用系统中增加或替换少量10 Git/s波道的扩容技术作了介绍,如波分复用终端设备改造方案,扩容工程所应用的技术及测试项目等。     

Diode multiplexer in the multi-Gbit/s range

A clocked multiplexer circuit was realised which provided 4.48 Gbit/s, 5 Gbit/s, and 7.84 Gbit/s output-pulse streams for p.c.m.-type input tributaries at 1.12 Gbit/s, 0.25 Gbit/s, and 1.12 Gbit/s, respectively. The circuit employed essentially ultra-broadband 180° hybrids, step-recovery diodes, and GaAs Schottky-barrier diodes. Output voltages up to 2 V were obtained across a load of 50 ?. The pulse width of the output pulses was approximately 100 ps.     

400 Gbit／s技术及应用探讨

随着400 Gbit／s启动规模商用,400 Gbit/s传输技术成为业界关注热点。本文首先介绍了400 Gbit／s发展背景、400 Gbit／s标准化最新进展,在此基础上详细分析了400 Gbit／s关键技术及方案选择,最后对400 Gbit／s未来应用前景进行了展望。     

AlGaAs/GaAs HBT IC's for high-speed lightwave transmission systems

The implementation of multigigabit-per-second optical communication systems requires many high-speed electronic circuit components that meet stringent performance requirements. Several important research prototype circuits for fiber-optic transmission, implemented in a baseline AlGaAs/GaAs HBT process, are discussed. These include a 20 Gb/s decision circuit, a 27 Gb/s 1:2 demultiplexer, a 30 GB/s 2:1 multiplexer, a 27 Gb/s 4:1 multiplexer, and a 11 Gb/s laser driver IC     

Applications of single and dual gate GaAs MESFETs for Gbit/s optical data transfer systems

Intrinsic large signal rise and fall times of less than 30 ps without charge storage demonstrate the potential of single and dual gate GaAs MESFETs for Gbit/s optical communication systems. The applications as signal regenerator, bit synchronizer, laser modulator, multiplexer, and demultiplexer are shown. Using only one dual gate GaAs MESFET clock and pulse shape regeneration as well as 1 Gbit/s laser modulation is performed. Bit synchronization is demonstrated up to 4 Gbit/s. 1 to 2 Gbit/s and 2 to 4 Gbit/s multiplexing as well as 2 to 1 Gbit/s demultiplexing with additional clock and pulse shape regeneration is shown using dual gate FETs. 2 to 4 Gbit/s multiplexing without clock regeneration is also accomplished using single gate GaAs MESFETs.     

Over-10-Gb/s IC's for future lightwave communications

This paper reviews research and development in NTT Laboratories on IC's faster than 10 Gb/s for future optical communication systems. Novel design and circuit techniques achieve such high-speed IC's and stable operation even in packages and modules. High-bit-rate operation of 10 Gb/s (10-GHz equalizing amplifier circuit, a 10-GHz clock recovery circuit, 10-Gb/s decision circuits, and 10-Gb/s multiplexers and demultiplexers) is obtained. 20-Gb/s operation is also achieved for some IC's. Future improvements using advanced device and circuit technologies are discussed, and bit rates over 40 Gb/s are predicted     

1.6 Tbit/s(40×40 Gbit/s)光通信传输系统

在国家自然科学基金网(NSFCNet)上已实现由400 km×10 Gbit/s传输链路直接升级的一路400 km×40 Gbit/s光传输实验的基础上,采用自行研制的40×40 Gbit/s载波抑制归零(CS-RZ)码多波长光发送源,进行了160 km的1.6 Tbit/s(40×40 Gbit/s)波分复用(WDM)光传输实验。实验结果表明,对于常规中短距离10 Gbit/s传输链路可以直接升级至40 Gbit/s。但是由于40 Gbit/s传输系统的色散容限小于60 ps/nm,而且传输光纤与色散补偿模块的色散斜率不匹配,要实现40通道40 Gbit/s的传输,必须对40个信道分别进行精细的色散补偿。这也说明,对于宽带的40 Gbit/s多波长系统,有必要优化设计或更新传输链路。     

支持40 Gbit/s路由器的传输技术研究

本文介绍了核心路由器40 Gbit/s高速接口的优点和传输系统为支持40 Gbit/s路由器所做的努力.例如40 Gbit/s WDM(波分复用)传输技术、40 Gbit/s IMUX(反向复用)技术等.在介绍这些技术的发展现状和优缺点的基础上,本文对40 Gbit/s传输技术的发展进行了预测.     

10- and 40-Gb/s forward error correction devices for optical communications

Two standard forward error correction (FEC) devices for 10- and 40-Gb/s optical systems are presented. The first FEC device includes RS(255, 239) FEC, BCH(4359, 4320) FEC, and standard compliant framing and performance monitoring functions. It can support a single 10-Gb/s channel or four asynchronous 2.5-Gb/s channels. The second FEC device implements RS(255, 239) FEC at a data rate of 40 Gb/s. This paper presents the key ideas applied to the design of Reed-Solomon (RS) decoder blocks in these devices, especially those for achieving high throughput and reducing complexity and power. Implemented in a 1.5-V, 0.16-/spl mu/m CMOS technology, the RS decoder in the 10-Gb/s, quad 2.5-Gb/s device has a core gate count of 424 K and consumes 343 mW; the 40-Gb/s RS decoder has a core gate count of 364 K and an estimated power consumption of 360 mW. The 40-Gb/s RS FEC is the highest throughput implementation reported to date.