SiGe HBT and BiCMOS technologies for optical transmission and wireless communication systems

Technologies for a self-aligned SiGe heterojunction bipolar transistor (HBT) and SiGe HBTs with CMOS transistors (SiGe BiCMOS) have been developed for use in optical transmission and wireless communication systems. n-Si cap/SiGe-base multilayer fabricated by selective epitaxial growth (SEG) was used to obtain both high-speed and low-power performance for the SiGe HBTs. The process except the SEG is almost completely compatible with well-established Si bipolar-CMOS technology, and the SiGe HBT and BiCMOS were fabricated on a 200-mm wafer line. High-quality passive elements, i.e., high-precision poly-Si resistors, a high-Q varactor, an MIM capacitor, and high-Q spiral inductors have also been developed to meet the demand for integration of the sophisticated functions. A cutoff frequency of 130 GHz, a maximum oscillation frequency of 180 GHz, and an ECL gate-delay time of 5.3 ps have been demonstrated for the SiGe HBTs. An IC chipset for 40-Gb/s optical-fiber links, a single-chip 10-Gb/s transceiver large-scale IC (LSI), a 5.8-GHz electronic toll collection transceiver IC, and other practical circuits have been implemented by applying the SiGe HBT or BiCMOS technique.     

High-sensitivity receiver optical preamplifiers

High-receiver sensitivities of -40.9, -44.3, -46.2, -49.0, and -51.3 dBm are reported at 2.4, 1.8, 1.2, 0.62, and 0.14 Gb/s, respectively, using a low-noise, 980-nm diode-pumped, erbium fiber amplifier in the receiver preamplifier configuration with all field usable components. This corresponds to a best sensitivity of 156 photons/bit at the input of the optical amplifier (96 photons/bit at the input of the erbium-doped fiber). Selection of a low-chirp laser-diode transmitter, an optical filter with a bandwidth appropriate for filtering the signal, and a low-noise electrical amplifier with appropriate bandwidth in the post detection stage are all critical to achieve very high-receiver sensitivities     

1.2 Gbit/s fully integrated transimpedance optical receiver OEIC for 1.3-1.55 mu m transmission systems

The design and performance characteristics of a 1.2 Gbit/s transimpedance receiver OEIC incorporating a high voltage gain, low input capacitance cascode amplifier and a 50 Omega driver is reported. The receiver exhibited an improvement of factor of two in bandwidth over those using a conventional single inverter gain stage. An optical sensitivity of -27.5 dBm for an error rate of 10/sup -9/ at 1.3 mu m wavelength has been obtained without bandwidth equalisation or noise filtering.<>     

光模数转换系统中数据存储与传输

设计了一种光模数转换(OADC)系统中后端高速数据的存储和传输方案.该方案基于主-从现场可编程逻辑门阵列(FPGA)的结构,采用DDR3 SDRAM作为存储介质,基于PCI Express总线通过存储器直接访问(DMA)机制,使数据高度输出,实现了单通道高速数据的实时存储与传输.仿真和测试表明,该方案能够满足单通道输入数据速率为2.56Gb/s的光模数转换系统的要求.     

A low cost optical storage server for near video-on-demand systems

A near video-on-demand system is one of the most economic and practical applications to provide high quality digital video services through a network in terms of cost, storage and network capacity requirements. In this paper, an optical storage server with a novel data placement and retrieval schemes is proposed for a near video-on-demand system. The proposed data placement scheme on the optical discs fully exploits the periodical broadcast characteristic of an NVOD service to optimize the disc bandwidth utilization. By further applying our retrieval schedule strategy, the buffer requirement of a system can be significantly reduced. In that way, the maximal number of supported streams with the minimal buffer requirement can be easily achieved, The storage system can be applied not only to CD-ROMs storing MPEG-1, but also to Digital Video Disks (DVDs) storing MPEG-2 in the near future     

BiCMOS circuits for DPCM coders in HDTV systems

Three different strategies used to enhance the speed performance of differential pulse-code-modulation (DPCM) coders are reviewed. The first strategy is the reduction of the number of components located in the time-critical recursive loop. The second is the use of a BiCMOS technology, and the third is the development of high-speed circuit techniques. Prototype chips prove that a 2.5-μm process is feasible for implementation of DPCM coders operating at 54 MHz. Another test structure shows a BiCMOS sequencer with 64 product terms running at 80 MHz with 125-mW power consumption     

Silicon-based optical receivers in BiCMOS technology for advanced optoelectronic integrated circuits

A double photodiode (DPD) and a phototransistor were implemented in an industrial 0.8 μm bipolar complementary metal oxide semiconductor (BiCMOS) n-well process. Both devices are 100% BiCMOS compatible, so that no process modifications were necessary. A −3 dB bandwidth of more than 200 MHz was measured for the DPD. The rise and fall times of the photodiode are less than 1 ns. By an optimized antireflection coating layer for a wavelength of 638 nm a quantum efficiency of η=95%, which corresponds to a responsivity of R=0.49 A/W, is achievable. A phototransistor with a light-sensitive area of 53×53 μm² was developed. Its current amplification of B=300 results in a much larger responsivity compared to the photodiodes. Measurements have shown a −3 dB bandwidth of 7.8 MHz for the phototransistor.     

A single-chip optical CMOS detector with in-situ demodulating and integrating readout for next-generation optical storage systems

In this paper, a new fully integrated detector architecture for pick-up units in optical storage systems is presented. It features a special high-frequency photodiode constellation for data recovery suitable for the needs of future optical storage systems. The functionality of standard detectors has been extended by using an additional 5 /spl times/ 5 low-frequency photodiode matrix for in-situ determination of the average spatial light power distribution across the detector. The six high-frequency paths exhibit bandwidths up to 135 MHz, and the maximum clock frequency for the low-frequency paths is 20 MHz. The detector has been fabricated in a standard 0.6-/spl mu/m CMOS process, and it operates at a 3.3-V power supply and occupies 1.78 /spl times/ 1.58 mm/sup 2/.     

High-sensitivity Hi-Lo germanium avalanche photodiode for 1.5 ?m-wavelength optical communication

A high-sensitivity small-detectable-area Hi-Lo germanium avalanche photodiode (Ge APD) was developed for use in 1.55 ?m wavelength optical communication systems. This device has Hi-Lo (p+nn?) impurity profile. Its detectable area is 30 ?m in diameter for single-mode optical-fibre use. The minimum average received signal level obtained was ?40.5 dBm (at 450 Mbit/s, ? = 1.55 ?m, BER = 10?9, return-to-zero). This is 0.7 dB better than the value for the 80?m diameter similar structure Ge APD.     

OEIC光接收机研究的湿法选择腐蚀

试验了用柠檬酸与双氧水系列腐蚀液来实现ＩｎＡｌ（Ｇａ）Ａｓ∶ＩｎＰ和ＩｎＧａＡｓ∶ＩｎＡｌＡｓ的选择腐蚀,达到了较好的效果,且工艺重复性好。同一单片上ＭＳＭ（金属－半导体－金属）光探测器的光响应度可达到０．５Ａ／Ｗ,ＨＥＭＴ器件最大跨导为３０５ｍＳ／ｍｍ,最大饱和电流密度为３５０ｍＡ／ｍｍ。完成了实现ＯＥＩＣ光接收机的关键一步。     

A 5-GHz-band multifunctional BiCMOS transceiver chip for GMSKmodulation wireless systems

This paper reports the first multifunctional 0.4-μm BiCMOS-based transceiver chip developed for 5-GHz-band Gaussian minimum-shift keying modulation wireless systems. The chip integrates a low-noise radio-frequency amplifier, a down-mixer, and an intermediate-frequency (IF) amplifier in the down-converter path; an IF amplifier, a limiter, an up-mixer, and a buffer amplifier in the up-converter path; and a frequency doubler and a local oscillator amplifier in the local oscillator path. The chip featuring gain attenuation as well as standby mode operation uses a single 2.6-5.2-V bias voltage and dissipates 56 mW in receive mode and 66 mW in transmit mode. The transceiver chip size is 3.0×2.4 mm²     

High-sensitivity optical chemsensor based on etched D-fibre Bragg gratings

A novel and simple optical chemsensor concept based on cladding etched Bragg gratings UV-inscribed in D-fibre is reported. The sensitisation process of the Bragg structure to the refractive index of surrounding-medium under HF-etching has been investigated. Two etched devices were used to measure the concentrations of sugar solution, giving sensitivity as high as 0.02 nm/%.     

Analysis of optical data storage systems - tracking performance with eccentricity

The tracking control performance of optical data storage systems is analyzed in the presence of the disc eccentricity. The eccentricity is the maximum deviation from the geometric center of the circular tracks and the rotating center of the disc, which is inevitable in practice. This is mainly caused by the inaccuracy of the tracking forming devices. In the paper, tracking control performance is discussed in terms of pull-in capability and steady track-following ability. Firstly, it will be explicitly shown that the pull-in capability will degrade in proportion to the multiplication of the eccentricity and rotational frequency. This analysis provides a guide for tracking controller design with reliable pull-in actions. Secondly, in order to improve the steady track-following performance, a feedforward compensation method is introduced, which is simple enough to be implemented in practice. Furthermore, an interesting connection to the disturbance observer approach in the time domain is examined.     

High-sensitivity direct-detection receiver with a 1.5 ?m optical preamplifier

A 1.5 ?n optical preamplifier was used to improve the sensitivity of a PINFET receiver by 12dB. The resonant optical amplifier provided 17dB of fibre-to-fibre gain including coupling losses in an isolator and a narrowband optical filter. The achieved sensitivity, -45.6 dBm at 500 Mbit/s, or 420 photons/bit, is the best reported for any direct-detection receiver and a factor of two better than previous results using optical amplifiers. However, the results are virtually identical to the best APD receiver results.     

A BJT translinear loop based optoelectronic integrated circuit with variable transimpedance for optical storage systems

A 0.35 μm SiGe BiCMOS optical receiver with voltage-controlled transimpedance is presented. A variable-gain current amplifier using a BJT translinear loop is applied. A transimpedance dynamic range of 1554 (63.8 dB) with the largest transimpedance of 2.84 MΩ, a bandwidth up to 379 MHz, and a transimpedance bandwidth product up to 168 TΩHz are achieved.     

Superdense optical storage

The CD-ROM has made optical storage a common computing resource. Soon, though, other optical technologies will be cramming even more data into still less space. Four technologies (high-density rewritable disks, optical tape, volume holographic storage and electron trapping) could far exceed today's storage capabilities. Nor are these technologies just research efforts in university or corporate laboratories; the focus is now on developing actual products, and small companies have already formed to do so. Here, the authors examine: what is the technology's current status; what are the challenges to its realization; and what are its chances for commercial success?     

Simple polarisation-independent optical circulator for optical transmission systems

A simple polarisation-independent optical circulator has been developed. The circulator consists of a 45°Y3Fe5O12 rotator and a quartz rotator and two polarising beam-splitting cubes. Measured insertion loss was about 1.3 dB at 1.32 ?m wavelength. The circulator was connected to graded-index multimode fibres using rod lenses.     

Photodetectors for optical communication systems

The characteristics of high-sensitivity photodetectors suitable for wide bandwidth optical communication systems are summarized. Photodiodes, photomultipliers, and photoconductive detectors for wavelengths from 0.3 µm to 10.6 µm are covered. The use of internal current gain by means of avalanche and electron multiplication and by means of optical heterodyne detection to increase sensitivity of high speed photodetectors is discussed. The application to visible and infrared laser communication systems is reviewed.     

InGaAsP channel HFET's on InP for OEIC applications

A model for the calculation of the input noise of a high impedance photoreceiver is proposed, taking into account the contributions of low-frequency characteristics of the FET. Simulations based on this approach show that excess gate leakage current and low-frequency excess noise, usually observed in InGaAs channel FET's, strongly penalize the photoreceiver sensitivity for low to medium data rates. New InGaAsP channel HFET's have been developed and fabricated to solve those problems, dc measurements on 1×100 μm² gate HFET's show good I_ds-V_ds characteristics with associated gate leakage currents lower than 200 nA. Promising ft of 18 GHz and f _max of 40 GHz have been recorded on 0.5×200 μm² gate transistors. Low-frequency gate and channel noise measurements demonstrate the suitability of InGaAsP channel HFET structure and technology for low noise applications. A hybrid pin-HFET high impedance photoreceiver has been assembled with a 1×150 μm ² gate transistor. A very close agreement is found between photoreceiver input noise predicted by our model and experimental results. Record sensitivities of 34.8 dBm at 622 Mbit/s and -28.7 dBm at 2.5 Gbit/s are inferred from noise measurements, confirming the strong potential of InGaAsP channel HFET's for the fabrication of high sensitivity photoreceivers operating at moderate data rates