Silicon bipolar chipset for SONET/SDH 10 Gb/s fiber-opticcommunication links

High-speed multiplexers, demultiplexers, frequency dividers, mixers, and amplifiers are key electronic components in high-speed fiber-optic communications systems such as SONET/SDH. In this paper, we present several important digital and analog integrated circuits (IC) which have been developed for use in SONET/SDH 10 Gb/s optical communication links. The circuits have been fabricated in MOSAIC 5E, an advanced silicon bipolar technology (f_T=26 GHz). The resulting chipset which amounts to a total of 10 IC's consists of multiplexers, demultiplexers, a regenerative frequency divider (2:1), a dual output limiting amplifier, and two different types of mixers for clock extraction. Specifically, the design and performance of these IC's and a hybrid clock recovery module are discussed. The high performance and potential low cost of this research chipset show that advanced silicon bipolar circuit technology can play an important role in future multigigabit fiber-optic communication systems     

针对10Gb/s线卡应用的灵活接口方案

许多网络应用都采用10Gb／s接口来减小通信瓶颈。例如,用户对低成本千兆以太网(GbE)接入和VPLS需求的不断高涨,推动着运营商投入巨大力量建设10GbE城域网。这些网络是对已经向10Gb／s SDH(STM-64)和DWDM(密集波分复用)发展的现有传输网络的补充。另外,这些网络所传输的内容一般缘于一个大的数据中心,而这些数据中心都是考虑用通过10Gb／s光纤通道接口连接到光通道交换机,进而和服务器联系在一起,并依次连接交换机和存储子系统。     

100Gb/s光放大器在数据链路采集中的应用

在网络高速发展的今天,对于网络中数据链路的监控尤为重要。本文介绍了100Gb/s光放大器的相关技术,提出了100Gb/s光放大器对于100Gb/s数据链路采集中的部署应用方案。     

A 5 Gb/s CMOS adaptive equalizer for serial link

A 5 Gb/s adaptive equalizer with a new adaptation scheme is presented here by using 0.13μm CMOS process.The circuit consists of the combination of equalizer amplifier,limiter amplifier and adaptation loop.The adaptive algorithm exploits both the low frequency gain loop and the equalizer loop to minimize the inter-symbol interference (ISI) for a variety of cable characteristics.In addition,an offset cancellation loop is used to alleviate the offset influence of the signal path.The adaptive equalizer core occupies an area of 0.3567 mm2 and consumes a power consumption of 81.7 mW with 1.8 V power supply.Experiment results demonstrate that the equalizer could compensate for a designed cable loss with 0.23 UI peak-to-peak jitter.     

应用于subLVDS接口的1.5Gb/s收发器设计

介绍了subLVDS接口的系统结构并给出一种改进的内部收发器实现电路.为了稳定直流工作点,在发送器内部加入与电源电压无关的自偏置电压源和共模负反馈电路;通过轨到轨预放大器,接收器的共模输入电压可以达到电源至地的范围.SMIC0.18μm 1P6M的工艺下,仿真结果表明该系统对随机输入数据的工作速度可以达到1.5Gb/s,工作温度范围为-40～120℃.     

A two-chip 1.5-GBd serial link interface

A silicon bipolar transmitter and receiver chip pair transfers parallel data across a 1.5-GBd serial link. A new `conditional-invert master transition' code and phase-locked loop that provide adjustment-free clock recovery and frame synchronization are described and analyzed. The packaged parts require no external components and operate over a range of 700 to 1500 MHz using an on-chip VCO. The line code and handshake protocol have been accepted by the serial-HIPPI implementor's group for serially transmitting 800-Mb/s HIPPI data, an ANSI standard, and by SCI-FI, an IEEE standard for interconnecting cooperating computers     

A 10 Gb/s ATM data synchronizer

Asynchronous transfer mode (ATM) data comes from different sources, and it is by nature bursty, hence causing the incoming phase and exact bit rate to vary from burst to burst. In order to retime the bursty data, a conventional yet low-Q clock recovery scheme could be used, but the downstream system components would have to cope with the consequent clock interruptions and variations in phase and frequency. This work presents a phase agile data synchronizer integrated circuit that retimes bursty ATM cells at 10 Gb/s to an external 10 GHz clock. The integrated circuit comprises an analog variable data delay, a phase detector, an edge detector, a loop filter, and a data retime. It has a total delay range of 200 pS. The integrated circuit has been fabricated in both AlGaAs/GaAs and InGaP/GaAs HBT technology     

Degradation-robust 850-nm vertical-cavity surface-emitting lasers for 25Gb/s optical data transmission

Highly efficient fast vertical-cavity surface-emitting lasers (VCSELs) for the 850-nm spectral range, promising for the development of optical interconnections with a data transmission rate of 25 Gbit/s per channel, are fabricated and studied. Lasers with a selectively oxidized current aperture 6 μm in diameter demonstrate multimode lasing with a quantum efficiency of 35–45% and a threshold current of 0.5–0.7 mA in the temperature range 20–85°C. According to the results of small-signal frequency analysis, the maximum modulation frequency of the lasers exceeds 17 GHz, with the rate of its increase with current exceeding 9 GHz/mA^1/2, which provides VCSEL operation at a rate of 25 Gbit/s in the entire working temperature range. Endurance tests for 3000 h did not reveal any sudden degradation of the lasers. The optical power at working point and the threshold current changed relative to that at the beginning of the tests by no more than 5 and 10%, respectively.     

120-GHz-band millimeter-wave photonic wireless link for 10-Gb/s data transmission

A 120-GHz-band wireless link that uses millimeter-wave (MMW) photonic techniques was developed. The output power and noise characteristics of 120-GHz-band MMWs generated by converting a 125-GHz optical subcarrier signal were evaluated. It was then shown that the noise characteristics of the 125-GHz signal generated with these photonic technologies is sufficient for 10-Gb/s data transmission. We constructed a compact 120-GHz-band wireless link system, and evaluated its data transmission characteristics. This system achieved error-free transmission of OC-192 and 10-GbE signals over a distance of more than 200 m with a received power of below -30 dBm.     

A Si-bipolar technology for optical fiber transmission rates above10 Gb/s

A multiplexer operating at up to 12 Gb/s has been demonstrated using a simple, but optimized, silicon bipolar technology with 2 μm lithography. Using this simple but optimized technology, a 12 Gb/s multiplexer was implemented. Circuit simulations predict the increase of the bit rate up to at least 15 Gb/s by changing to the 1.5 μm lithography. The results of experimental investigations and circuit simulations show that low-cost silicon-based bipolar circuits will be available for future optical-fiber transmission systems with data rates higher than 10 Gb/s     

A 2.4 Gb/s/pin simultaneous bidirectional parallel link withper-pin skew compensation

This paper describes voltage and timing margins and design trade-offs in low-cost parallel links. Results from a transceiver prototype demonstrate that per-pin skew compensation improves timing margins in these parallel links and can be implemented with reasonable cost overhead. Single-ended and simultaneous bidirectional links are viable alternatives to the traditional differential and unidirectional systems-these links require fewer pins and wires for the same bandwidth, and the additional noise sources, while significant, can be managed by careful circuit and package design     

Silicon oxide-planarized single-mode 850-nm VCSELs with TO package for 10 Gb/s data transmission

In this letter, we report on an alternative method to fabricate a high-efficiency planar-type oxide-confined 850-nm vertical-cavity surface-emitting lasers (VCSELs). The planarized process of VCSELs was to use the silicon oxide as the buried layer. As a result, these devices with an oxidized aperture of 3 /spl mu/m in diameter exhibit a single-transverse mode behavior throughout the operation current range. In addition, the static characteristics of VCSELs at 300 K include a threshold current of 0.52mA corresponding to a threshold voltage of 2.2 V, a maximum single transverse-mode light output power of 1.13 mW at 4.5 mA, and an external differential quantum efficiency of 35%. On the other hand, this TO-packaged planar-type 850-nm VCSEL for back-to-back test shows a wide open along with symmetric eye diagram and could also pass the 10 Gb/s mask as operating at 10.3 Gb/s and 4 mA. Furthermore, the VCSEL can still keep the eye diagram open and symmetric after the 66-m multi-mode fiber transmission and has a power penalty of 6.6 dB because of fiber dispersion for 10.3 Gb/s data rate at a bit error rate of 10/sup -11/. These results confirm the excellent high-speed performance of SiO/sub x/-planarized VCSELs as compared to the polyimide-planarized VCSELs.     

4 Gb/s soliton data transmission over 136 km using erbium dopedfiber amplifiers

The use of semiconductor-laser-pumped erbium-doped fiber amplifiers and an externally modulated mode-locked external-cavity semiconductor laser to obtain soliton data transmission at 4 Gb/s over 136 km of nondispersion shifted fiber is described. After 136 km of transmission and at low pulse powers, the ~80 ps fiber input pulse width was broadened to ~150 ps. At high pulse powers the output pulse width was maintained at 80 ps, as expected for N=1 solitons. N =3 solitons were also observed at lower data rates     

20 Gb/s optical soliton data transmission over 70 km usingdistributed fiber amplifiers

20 Gb/s optical soliton data transmission is demonstrated over 70 km. Highly efficient distributed Raman amplifiers for fiber-loss compensation are realized by using high Δn dispersion-shifted single-mode fibers pumped by laser diodes. To achieve high bit rate transmission, optical multiplexing and demultiplexing techniques are also employed. The bit error rate (BER) performance dependence on the input peak power of the optical pulse is measured. No power penalty can be seen at the input peak power required for transmitting optical solitons while the BER performance degrades when decreasing the input peak power     

Advanced components and sub-system solutions for 40 Gb/s transmission

With the commissioning of the latest 10-Gb/s systems, vendors are now in the process of developing architectures for their next-generation products. 40-Gb/s components and subsystems are currently in development to address the necessities of these next-generation systems. The top three challenges associated with 40-Gb/s transmission are optical signal-to-noise ratio, dispersion, and high-speed components. In order to realize 40-Gb/s transmission, new component and subsystem developments are crucial. This paper reviews the latest transmission technologies and dispersion compensation techniques developed to fulfill 40-Gb/s transmission system requirements.     

基于标准CMOS工艺的1.5Gb/s单片集成光接收机

A monolithically integrated optical receiver, including the photodetector, has been realized in Chartered 0.35μm EEPROM CMOS technology for 850 nm optical communication. The optical receiver consists of a differential photodetector, a differential transimpedance amplifier, three limiting amplifiers and an output circuit. The experiment results show that the receiver achieves an 875 MHz 3 dB bandwidth, and a data rate of 1.5 Gb/s is achieved at a bit-error-rate of 10-9. The chip dissipates 60 mW under a single 3.3 V supply.     

252 km repeaterless 10 Gb/s transmission demonstration

Using a practical erbium-doped fiber postamplifier, a dual-stage optical preamplifier, a lithium niobate Mach-Zehnder external modulator and a dispersion-shifted line fiber, IM/DD repeaterless transmission over 252 km at 10 Gb/s with a wavelength-independent receiver sensitivity in the 1530-1565-nm range is achieved     

A 1.5 Gb/s monolithically integrated optical receiver in the standard CMOS process

A monolithically integrated optical receiver, including the photodetector, has been realized in Chartered 0.35 μm EEPROM CMOS technology for 850 nm optical communication. The optical receiver consists of a differential photodetector, a differential transimpedance amplifier, three limiting amplifiers and an output circuit. The experiment results show that the receiver achieves an 875 MHz 3 dB bandwidth, and a data rate of 1.5 Gb/s is achieved at a bit-error-rate of 10~(-9). The chip dissipates 60 mW under a single 3.3 V supply.     

3.6 Gb/s all laser-diode optical soliton transmission

3.6-Gb/s optical soliton transmission using a gain-switched 1.55-μm distributed-feedback laser diode and a Ti:LiNbO₃ intensity modulator is demonstrated. An Er³⁺-doped fiber amplifier and a Raman amplifier, both pumped by 1.48-μm laser diodes, are used for achieving intense optical pulses and fiber-loss compensation, respectively. The intensity-modulation direct-detection optical receiver of a commercial F-1.6 G system is used to measure the bit-error rate     

A quad 0.6-3.2 Gb/s/channel interference-free CMOS transceiver for backplane serial link

A quad-channel 0.6-3.2 Gb/s/channnel transceiver using eight independent phase-locked loops (PLLs) shows a 1-ps rms random jitter performance without interchannel interference. The PLL employs a folded starved inverter with high supply/substrate noise immunity and an analog coarse-tuning scheme for both seamless frequency acquisition and N-fold voltage-controlled-oscillator (VCO) gain reduction. A fixed-interval charge pumping is adopted for wide pumping-current range and large jitter tolerance. A wide-range delayed-locked loop (DLL) is utilized as a clock and reset generator for an elastic buffer. The transceiver, implemented in a 0.18-/spl mu/m CMOS technology, operates across a 30-in FR-4 backplane up to 3.2 Gb/s/ch with a bit-error rate of less than 10/sup -13/.