40-Gb/s Direct Modulation With High Extinction Ratio Operation of 1.3-μm InGaAlAs Multiquantum Well Ridge Waveguide Distributed Feedback Lasers

Direct modulation at 40 Gb/s of a 1.3-mum InGaAlAs distributed feedback ridge waveguide laser is experimentally demonstrated. By combination of the high differential gain of an InGaAlAs multiquantum well active layer, a short cavity length of 100 mum, and a low-resistance notch-free grating, it achieves high bandwidth of 29 GHz and high-extinction ratio of 5 dB at 40-Gb/s modulation. Moreover, the laser operates at a record maximum ambient temperature of 60degC under 40-Gb/s directly modulation. It also achieves 40-Gb/s modulated transmission over 2 km with a low power penalty of 0.25 dB at 25degC .     

1.3-μm GaInAsN Vertical-Cavity Surface-Emitting Lasers by Oxide-Planarized and Surface-Relief Processes for Single-Mode Operation

In this letter, we investigate and characterize the 1.3-mum single-mode vertical-cavity surface-emitting lasers (VCSELs) with two GaInAsN strained multiple quantum wells as the active region. Surface relief technique and a thick silicon oxide were used for the spatial mode filtering and the planarization processing, respectively. The VCSELs with a 5-mum-diameter surface-relief aperture and a 12-mum-diameter oxide-confined aperture at room temperature exhibit a threshold current of 3 mA, a slope efficiency of 0.14 mW/mA, a maximum operation temperature of 90 degC, and a single-mode behavior. These VCSELs show a maximum light output power of 1 mW for the single fundamental mode with a transverse-mode suppression of more than 30 dB and also show a clear eye-opening feature operated at 2.488 Gb/s and 12.6 mA     

A Fully Integrated 10-Gb/s Receiver With Adaptive Optical Dispersion Equalizer in 0.13-μm CMOS

A 10 Gb/s receiver, containing an adaptive equalizer, a clock and data recovery, and a de-multiplexer, is implemented in 0.13-mum CMOS. The chip is intended for long-haul optical fiber links where chromatic and polarization mode dispersions are reach-limiting factors. The equalization is performed by a continuous time filter and a two-tap decision feedback equalizer while automatic threshold and phase adjustments are embedded in the CDR. Use of an analog equalizer with digital adaptation garners total power dissipation of 950 mW. Error-free operation over 200 km of single mode fiber is demonstrated. With 140 km of single mode fiber, optical signal to noise ratio penalty is only 2dB. Differential group delay of 100 ps can also be tolerated     

Dynamics and Temperature-Dependence of 1.3-μm GaInNAs Double Quantum-Well Lasers

We have measured the small-signal modulation response of 1.3-mum ridge waveguide GaInNAs double quantum-well lasers over a wide range of temperatures (25 degC-110 degC) and analyzed the temperature dependence of the modulation bandwidth and the various bandwidth limiting effects. The lasers have low threshold currents and high differential efficiencies with small temperature dependencies. A short-cavity (350 mum) laser has a modulation bandwidth as high as 17 GHz at room temperature, reducing to 4 GHz at 110 degC, while a laser with a longer cavity (580 mum) maintains a bandwidth of 8.6 GHz at 110 degC. We find that at all ambient temperatures the maximum bandwidth is limited by thermal effects as the temperature increases with current due to self-heating. The reduction and subsequent saturation of the resonance frequency with increasing current is due to a reduction of the differential gain and an increase of the threshold current with increasing temperature. We find large values for the differential gain and the gain compression factor. The differential gain decreases linearly with temperature while there is only a weak temperature dependence of the gain compression. At the highest temperature we also find evidence for transport effects that increase the damping rate and reduce the intrinsic bandwidth     

40-Gb/s High-Gain Distributed Amplifiers With Cascaded Gain Stages in 0.18-μm CMOS

A novel circuit topology for high-gain distributed amplifiers is presented in this study. Based on the conventional distributed architecture, the gain cells are realized by cascading cas- code stages for gain enhancement. In addition, the stagger-tuning technique is extensively utilized in the design of the cascode stages as well as the cascaded stages, leading to significant improvement in terms of the operating bandwidth and the gain flatness. With the proposed circuit architecture, two amplifiers are implemented in a standard 0.18-mum CMOS technology. The amplifier with a 3 times 3 configuration exhibits a gain of 16.2 dB and a 3-dB bandwidth of 33.4 GHz, while the one in a form of 2 times 4 demonstrates a gain of 20 dB and a bandwidth of 39.4 GHz. Consuming a dc power of 260 mW from a 2.8-V supply voltage, both circuits provide clear eye-opening with a pseudorandom bit sequence (PRBS) at 40 Gb/s.     

1.3-μm Quantum-Dot Multisection Superluminescent Diodes With Extremely Broad Bandwidth

A novel ridge-waveguide quantum-dot superluminescent diode is reported. The multisection configuration enables the simultaneous realization of ultrawide 3-dB bandwidth (>150 nm) and an output power greater than 1 mW     

Systematic Study of the Effects of Modulation p-Doping on 1.3-μm Quantum-Dot Lasers

The effects of modulation p-doping on 1.3-mum InGaAs-InAs quantum-dot (QD) lasers are systematically investigated using a series of wafers with doping levels from 0 to 18 acceptors per QD. Various characterization techniques for both laser diodes and surface-emitting light-emitting diode structures are employed. We report: 1) how the level of modulation p-doping alters the length dependant laser characteristics (in turn providing insight on various key parameters); 2) the effect of modulation p-doping on the temperature dependence of a number of factors and its role in obtaining an infinite T₀; 3) how increasing concentrations of modulation p-doping affects the saturated gain, differential gain, and gain profile of the lasers; and finally, 4) the effect modulation p-doping has on the small signal modulation properties of 1.3-mum QD lasers. In each of these areas, the role of modulation p-doping is established and critically discussed.     

2.5-Gb/s Hybrid Single-Mode and Multimode Fiber Transmission of 1.5-μm Wavelength VCSEL

We report, for the first time, a successful 2.5-Gb/s transmission performance of a 1.5-mum emission monolithic vertical-cavity surface-emitting laser (VCSEL) over hybrid links composed of 25-km-long conventional single-mode fibers (SMFs) and a 2.2-km-long 50-mum core multimode fibers (MMFs). This result suggests that 1.5-mum wavelength VCSELs can be effectively used for multigigabit-per-second transmission over hybrid links interconnecting SMF-based long-distance and (or) subscriber network lines with MMF-based local-area network lines in the future ubiquitous network era     

1.25/2.5-Gb/s Dual Bit-Rate Burst-Mode Clock Recovery Circuits in 0.18-μm CMOS Technology

A burst-mode clock recovery circuit with a novel dual bit-rate structure is presented. It utilizes two gated oscillators to align the clock with data edges and can operate in half-rate clocking mode, doubling data throughput, as well as in full-rate clocking mode. The gated oscillator reset-phase control scheme causes the starting phase of gated oscillators to alternate repeatedly between 0deg and 180deg according to the current clock phase. A prototype chip was designed with the 0.18-mum CMOS technology, and a 1.25/2.5-Gb/s dual-mode operation was verified by measurement     

10-Gb/s Operation of RSOA for WDM PON

We report on the 10-Gb/s operation of the reflective semiconductor optical amplifier (RSOA) for the next-generation wavelength-division-multiplexed passive optical network (WDM PON). The bandwidth of the RSOA used in this experiment is merely 2.2 GHz. Nevertheless, a clear eye opening is obtained at 10 Gb/s by using the electronic equalizer processed offline. We investigate the impacts of the network's operating conditions (such as the injection power to the RSOA and the fiber length) on the performances of these equalizers. The results show that the RSOA-based WDM PON is operable at 10 Gb/s and the maximum reach can be extended to ${>}$ 20 km with the help of the forward error correction codes.      

1.3–1.55-μ m CMOS/InP Optoelectronic Receiver Using a Self-Aligned Wafer Level Integration Technology

A heterogeneous 10-Gb/s 1.3- to 1.55-mum optoelectronic receiver is designed and fabricated using a complementary metal-oxide-semiconductor transimpedance amplifier and an InGaAs-InP PIN (p-type, intrinsic, n-type diode) photodiode. The receiver is heterogeneously integrated based on a batch fabrication process which promises low fabrication cost. The receiver measures a transimpedance gain of higher than 50 dBldrOmega over a bandwidth of 6 GHz and demonstrates an open eye diagram with a 1.55-mum 10-Gb/s light source.     

Transmission properties of 1.3-/spl mu/m InGaAlAs MQW FP lasers in 10-gb/s uncooled operation

Limitations on transmission by an uncooled InGaAlAs Fabry-Perot (FP) laser in 10-Gb/s operation are experimentally and theoretically investigated. The InGaAlAs laser has both high relaxation-oscillation frequency and superior light-current characteristics over a wide temperature range, making it suitable for uncooled operation at 10 Gb/s. Over most of the temperature range used in transmission testing with standard-dispersion fiber, a small power penalty of 1 dB for a bit error rate (BER) of 10/sup -12/ was obtained in transmission over 4-7 km at the measured temperature range, whereas an error floor was seen in transmission over greater distance, despite the negative chromatic dispersion between the fiber and laser light. Theoretical analysis of these results indicates that mode-partition noise (MPN) imposes the major limitation on transmission distance. Moreover, the minimum transmission distance was estimated as 2.1 km, even when the production tolerance of lasing characteristics and zero-dispersion range of installed fiber are taken into account.     

MOVPE生长1.3 μm无致冷AlGaInAs/InP应变补偿量子阱激光器研究

通过低压金属有机化学气相外延 (LP MOVPE)工艺生长了AlGaInAs应变补偿量子阱材料 ,通过X射线双晶衍射、光荧光、二次离子质谱的测试分析得到了材料生长的优化工艺参数 ,降低了材料中的氧杂质含量 ,得到了高质量AlGaInAs应变补偿量子阱材料 ,室温光致发光半宽FWHM =2 6meV。采用此外延材料成功制作了 1 3μm无致冷AlGaInAs应变量子阱激光器 ,器件测试结果为 :激射波长 :12 90nm≤ λ≤ 1330nm ;阈值电流 :Ith(2 5℃ )≤15mA ;Ith(85℃ )≤ 2 5mA ;量子效率变化 :Δηex(2 5～ 85℃ )≤ 1 0dB。     

1-μm Enhancement Mode GaAs N-Channel MOSFETs With Transconductance Exceeding 250 mS/mm

In this letter, 1-mum GaAs-based enhancement-mode n-channel devices with channel mobility of 5500 cm²/Vmiddots and g _m exceeding 250 mS/mm have been fabricated. The measured device parameters including threshold voltage V_th, maximum extrinsic transconductance g_m, saturation current I_dss , on-resistance R_on, and gate current are 0.11 V, 254 mS/mm, 380 mA/mm, 4.5 Omegamiddotmm, and < 56 pA for a first wafer and 0.08 V, 229 mS/mm, 443 mA/mm, 4.5 Omegamiddotmm, and < 90 pA for a second wafer, respectively. With an intrinsic transconductance g_mi of 434 mS/mm, GaAs enhancement-mode MOSFETs have reached expected intrinsic device performance     

A 3.125-Gbit/s Parallel Optical Receiver in 0.13-μm CMOS With Direct Crosstalk Power Penalty Measurement Capability

We introduce a new method to measure the crosstalk power penalty in an arrayed environment by using an on-chip pseudorandom-bit-sequence generator to drive the aggressors. The proposed method is implemented in a three-channel 3.125-Gbit/s/ ch parallel receiver. Experimental results are presented including measurements of bit-error rate and crosstalk power penalty for 2.5and 3.125-Gbit/s operations. The measured crosstalk power penalty is less than 1 dB at both data rates. The test chip was designed in a standard 0.13-mum CMOS process     

A Low Power Folded Mixer for UWB System Applications in 0.18-μm CMOS Technology

This letter presents a wideband mixer using a commercial 0.18-mum CMOS technology process for ultra-wideband (UWB) system applications. To achieve wideband frequency response and low dc power consumption for UWB system applications, the folded approach is utilized to reduce supply voltage as well as dc power consumption, and wideband input matching network is used to achieve wideband frequency response. The measured results show that the proposed mixer demonstrates a wideband frequency response from 0.2 to 16GHz with a conversion gain of better than 5.3dB. The dc power consumption is 15mW under a supply voltage of 1.8V, with a compact size of 0.68mmtimes0.65mm     

A 6-bit 600-MS/s 5.3-mW Asynchronous ADC in 0.13-μm CMOS

An asynchronous analog-to-digital converter (ADC) based on successive approximation is used to provide a high-speed (600-MS/s) and medium-resolution (6-bit) conversion. A high input bandwidth (>4 GHz) was achieved which allows its use in RF subsampling applications. By using asynchronous processing techniques, it avoids clocks at higher than the sample rate and speeds up a nonbinary successive approximation algorithm utilizing a series nonbinary capacitive ladder with digital radix calibration. The sample rate of 600 MS/s was achieved by time-interleaving two single ADCs, which were fabricated in a 0.13-mum standard digital CMOS process. The ADC achieves a peak SNDR of 34 dB, while only consuming an active area of 0.12mm² and having power consumption of 5.3 mW     

On the reliability of 1.3-µm InGaAsP/InP edge-emitting LED́s for optical-fiber communication

This study of the reliability of 1.3-μm double heterojunction edge-emitting LED's indicates that edge-emitting LED's mounted with Au0.8Sn0.2solder have an activation energy of 0.9 eV for degradation and extrapolated lifetimes of2 times 10^{8}h at room temperature. A study of 1.3-μm LED's grown by LPE and VPE show them to be comparable in operating life. The temperature dependence of the light output (P) of the edge-emitting LED's is given byP alpha exp(-Delta T/75K). The study also showed that lattice mismatch up to 0.31 percent at the InGaAsP/InP heterojunction does not effect reliability.     

A Fully Integrated 4 × 10-Gb/s DWDM Optoelectronic Transceiver Implemented in a Standard 0.13 μm CMOS SOI Technology

Optical and electronic building blocks required for DWDM transceivers have been integrated in a 0.13 mum CMOS SOI technology. Using these building blocks, a 4 x 10-Gb/s single-chip DWDM optoelectronic transceiver with 200 GHz channel spacing has been demonstrated. The DWDM transceiver demonstrates an unprecedented level of optoelectronic system integration, bringing all required optical and electronic transceiver functions together on a single SOI substrate. An aggregate data rate of 40 Gb/s was achieved over a single fiber, with a BER of less than 10^-12 and a power consumption of 3.5 W.     

10-Gb/s Inductorless CDRs With Digital Frequency Calibration

Two 10-Gb/s inductorless clock and data recovery (CDR) circuits using different gated digital-controlled oscillators (GDCO) are presented. A digital frequency calibration is adopted to save the power consumption and chip area. They have been fabricated in 0.18-$mu{hbox{m}}$ CMOS process. By using the complementary gating technique, the first CDR circuit occupies an active area of 0.16 ${hbox{mm}}^{2}$ and draws 36 mW from a 1.8 V supply. The measured rms jitter and peak-to-peak jitter is 8.5 ps and 42.7 ps , respectively. By using the quadrature gating technique, the second CDR circuit consumes an active area of 0.25 ${hbox{mm}}^{2}$ and its power consumption of 56 mW. The measured rms jitter and peak-to-peak jitter is 3.4 ps and 21.8 ps, respectively. The power of the second CDR circuit is higher than that of the first one but its jitter is reduced.