1.25-Gb/s Operation of a Spectrum-Sliced Fabry–PÉrot Laser Diode With Intensity Noise Suppression by a Second Fabry–PÉrot Laser Diode

We propose a low-cost solution for the intensity noise suppression in the spectrum-sliced Fabry-Perot laser diode (F-P LD), which is achieved by placing an F-P LD at the receiver region. The F-P LD at the receiver region provides the intensity noise suppression of about 10 dB as well as the increase of the received optical power for the spectrum-sliced optical signal. The Q-factor is improved about 5.9 at a data rate of 1.25 Gb/s. As a result, we successfully demonstrate 10-km error-free transmission at 1.25-Gb/s signal with a transmission penalty of less than 0.5 dB. It is also found that the low spectrum-sliced power of -22 dBm achieves the relative intensity noise level of -112.5 dB/Hz, which is almost independent of the operation current.     

Four channel integrated DFB laser array with tunable wavelengthspacing and 40-Gb/s signal transmission capacity

A four-channel distributed-feedback (DFB) laser array integrated with four heating filaments has been fabricated for high-density wavelength-division-multiplexing systems. The DFB lasers have a threshold current of 4 mA at room temperature. By changing the power in the heater, the wavelength of each laser can be continuously tuned by as much as 5 nm. Therefore, a tunable wavelength spacing anywhere from 1 nm to 2 nm can be achieved. Each laser can operate at 10 Gb/s. However, the bias current has to be increased to avoid the degradation of the eye pattern as the wavelength is thermally tuned over 2 nm. An electric crosstalk of 0.6 dB is measured when two adjacent lasers are modulated at 10 Gb/s simultaneously     

Dynamic and CW linewidth measurements of buried heterostructuredistributed feedback lasers

Measurements of frequency chirp as a function of modulation current, data rate, and bias level for the etched-mesa buried heterostructure distributed feedback (EMBH-DFB) laser are presented. The results show that the chirp increases with increasing modulation current and is significantly larger if the laser off-state is below threshold than if it is above-threshold. The 20-dB down chirp widths are in the range of 4 to 6 Å for 40 mA of modulation current at 5 Gb//s under above threshold bias. Using the EMBH-DFB laser, a system experiment over 22-km fiber at 16 Gb/s has been carried out which shows less than 0.5 dB dispersion power penalty. The continuous-wave (CW) linewidths of the asymmetric facet-coated DFB lasers are in the range of 10 to 40 MHz at 6 mW of output power. This wide range arises principally from a variation of the phase of the grating at the high-reflectivity coated facet     

High-speed modulation of 850-nm intracavity contacted shallowimplant-apertured vertical-cavity surface-emitting lasers

GaAs-AlGaAs quantum-well (850 nn) vertical-cavity surface-emitting lasers, with lateral current injection and shallow implanted apertures, show small signal modulation bandwidths of at least 11 GHz and large signal data rates of at least 10 Gb/s. The devices achieved a maximum output power of 2.1 mW, with a threshold current and voltage of 1 mA and 1.71 V, respectively. The shallow implantation step provides photolithographically precise aperture formation (using O⁺ ions), for efficient lateral current injection into the quantum-well active region of the laser, from intracavity contacts. The device aperture was 7 μm in diameter, and the opening in the annular top contact was 13 μm in diameter. The optical spectrum showed several transverse modes     

15-GHz modulation bandwidth, ultralow-chirp 1.55-μm directlymodulated hybrid distributed Bragg reflector (HDBR) laser source

A hybrid source has been realized, integrating a fast Fabry-Perot laser and a fiber grating. The device has shown very good performances in the 1530-1570-nm range, obtaining 16 mA of threshold current at 20°C, 1.6-mW fiber optical power and 48 dB of sidemode suppression ratio at 50 mA bias current. The cavity length was designed to achieve a good tradeoff between chirp reduction and increasing speed. The device has shown for the first time, to our knowledge, more than 15 GHz of small-signal modulation bandwidth, and 10-Gb/s modulation capability. Moreover, a penalty-free transmission experiment at 2.5 Gb/s over 100 km of standard fiber has confirmed the very low wavelength chirp of the device. These previous characteristics together with an extremely low temperature dependence (<0.02 nm/°C) make the hybrid distributed Bragg reflector (HDBR) particularly suitable for dense wavelength-division-multiplexing systems     

Characterization of Fabry–Perot laser diodes injection locked by spectrum sliced ASE noise in WDM-PON

We experimentally evaluate the performance of Fabry–Perot laser diodes (FPLDs) injection locked by spectrum sliced amplified spontaneous emission (ASE) noise for transmission at 1.25 Gb/s. We characterize the injection locked FPLDs in terms of front-facet reflectivity, operation temperature, bias current and injection locked mode location. Experiment results show that the FPLD performance is strongly dependent on the front-facet reflectivity. Therefore a reasonable range of front-facet reflectivity for FPLDs is recommended. Operating the lasers at low temperature has better receiver sensitivity, while operating at high temperature has slightly broader operation range for injected ASE power. There is an optimal bias for a given injection power and the operation range for bias current is increased for higher injection power. Injection locked mode location also affects the performance of FPLDs.     

ROF系统中基于SOA非线性效应的光子上变频技术研究

在光载射频（ROF）系统中,为了将承载信息的光基带信号上变频到微波／毫米波波段,本文基于半导体光放大器（SOA）中的交叉增益调制（xGM）和交叉相位调制（XPM）效应实现了光子上变频：即实现了1．25Gb／s基带信号到30GHz的毫米波信号的转换。文中分析了SOA驱动电流的变化（50～200mA）和信号光与本振光波长间...     

高速光突发模式接收机设计

介绍了一种高速光突发模式接收机。整形电路采用直流耦合跨阻抗前馈式结构。突发同步恢复电路采用一种新颖的固定相位调节振荡器。仿真表明：在传输速率为1．25Gb／s，误码率BER≤10^-9时，接收灵敏度为-25dBm（平均光功率）。最大可接收光功率-1dBm，动态范围可高达24dB，两分组信号保护时间为20ns。对速率为5Gb／s的NRZ突发数据可在10ps之内建立比特同步。     

Integrated laser-diode voltage driver for 20-Gb/s optical systemsusing 0.3-μm gate length quantum-well HEMT's

An integrated laser-diode voltage driver (LDVD) making use of enhancement/depletion AlGaAs-GaAs quantum-well high electron mobility transistors (QW HEMTs) with gate lengths of 0.3 μm has been developed. Its large signal bandwidth is 12 GHz. Eye diagrams of the output signal at bit rates up to 8 Gb/s show an opening similar to that of the input signal. Supporting material is given indicating that the LDVD might operate at bit rates up to 20 Gb/s. The maximum output current is over 90 mA; the maximum modulation voltage of 800 mV corresponds to 40-mA modulation current for a laser diode with 20-Ω dynamic resistance. The power consumption is less than 500 mW     

Gigabit-per-second cryogenic optical link using optimizedlow-temperature AlGaAs-GaAs vertical-cavity surface-emitting lasers

We describe the design of GaAs-AlGaAs vertical-cavity surface-emitting lasers (VCSELs) that are optimized for operation at very low temperatures and the experimental demonstration of a free-space optical interconnect for cryogenic electronic systems using a VCSEL. We demonstrate high-speed modulation of the optical link at a data rate of up to 2 Gb/s at 77 K, with a very low bit-error rate of <10^-13 , and thermally stable operation is achieved over a wide range of cryogenic temperatures without laser bias current compensation. Cryogenic VCSELs with excellent lasing characteristics have been achieved over the entire temperature range from 150 K to 6 K, including high output power (22 mW), high power-conversion efficiency (32%), high slope efficiency (~100%), low threshold voltage (1.75 V) and current (1.7 mA), as well as a high-modulation bandwidth (12 GHz) for a 16 μm diameter device at 80 K     

Free space adaptive optical interconnect at 1.25 Gb/s, with beam steering using a ferroelectric liquid-crystal SLM

A free space adaptive optical interconnect is reported, in which an optically modulated channel from a vertical-cavity surface-emitting laser at 1.25 Gb/s is steered using reconfigurable binary phase gratings displayed on a ferroelectric liquid crystal on silicon (LCOS) spatial light modulator (SLM), to correct for misalignment. The optical system, and addressing scheme to maintain a transparent optical path, is described. The measured optical losses total 13.6 dB, sufficient to give a bit error rate (BER) of 10/sup -12/ with current optical transmitter and receiver technology. This is, to our knowledge, the first demonstration of a high-speed data transmission through an adaptive optical interconnect using an "off-the-shelf" commercial ferroelectric display panel.     

2.5Gb/sGaAs激光器高速驱动电路

研制出一种实用化的ＧａＡｓ激光器高速驱动电路,该电路采用源耦合场效应管逻辑电路形式,０．８μｍ栅工艺,全离子注入平面工艺,单电源（－５．２Ｖ）供电。并给出了研究结果：最大驱动电流可达４５ｍＡ,数据传输速率２．５Ｇｂ／ｓ。     

Development of GPON upstream physical-media-dependent prototypes

This paper presents three new gigabit-capable passive optical network (GPON) physical-media-dependent (PMD) prototypes: a burst-mode optical transmitter, an avalanche photodiode/transimpedance amplifier (APD-TIA), and a burst-mode optical receiver. With these, point-to-multipoint (P2MP) upstream transmission can be realized in a high-performance GPON at 1.25 Gb/s. Performance measurements on the new burst-mode upstream PMD modules comply with GPON uplink simulations. The laser transmitter can quickly set and stabilize the launched optical power level over a wide temperature range with better than 1-dB accuracy. A burst-mode receiver sensitivity of -32.8 dBm (BER=10/sup -10/) is measured, combined with a dynamic range of 23 dB at a fixed APD avalanche gain of 6. Full compliance is achieved with the recently approved ITU-T Recommendation G.984.2 supporting an innovative overall power-leveling mechanism.     

High-Power and High-Speed Zn-Diffusion Single Fundamental-Mode Vertical-Cavity Surface-Emitting Lasers at 850-nm Wavelength

We demonstrate a high-performance Zn-diffusion single-mode 850-nm vertical-cavity surface-emitting laser, which has a low threshold current (0.5 mA), high differential efficiency (80%), high modulation current efficiency (8.2 GHz/mA), and can sustain the single fundamental-mode output with a maximum output power of 7.3 mW under the full range of bias currents. With this device we can achieve 10 Gb/s eye-opening at a low bias current (1.8 mA) and a peak-to-peak driving-voltage of 0.5 V, which corresponds to a very high data-rate/power-dissipation ratio of 6.5 Gps/mW.     

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 versatile Si-bipolar driver circuit with high output voltageswing for external and direct laser modulation in 10 Gb/s optical-fiberlinks

A monolithic integrated driver circuit developed for laser modulation in a 10 Gb/s optical-fiber link is presented. The IC was fabricated in a self-aligned double-polysilicon Si-bipolar production technology with f_T≈25 GHz. The circuit can be operated up to 14 Gb/s with a maximum output voltage swing as high as 3.6 V at 50 Ω load (corresponding to an internal current swing of 108 mA), which allows the circuit to drive external modulators. In addition, the circuit can be used for direct laser modulation at 10 Gb/s, since the output current swing can easily be controlled over a wide range (e.g., from 15 mA to 60 mA). Problems in the design of such driver circuits as well as their solutions are discussed in detail     

2.5 Gb/s laser-driver GaAS IC

A laser-diode driver GaAs IC incorporating an optional NRZ/RZ (non-return-to-zero/return-to-zero) conversion facility, having ECL (emitter-coupled logic) and SCFL (source-coupled FET logic)-compatible inputs and providing a 0-60-mA adjustable output current into a 50-Ω/5-V termination at bit rates up to 2 Gb/s NRZ and maintaining a clear eye opening of 50 mA at 2.5 Gb/s NRZ bit rate has been designed, using a commercial 1-μm gate-length (F_τ=12 GHz) GaAs MESFET foundry service. The high maximum output current is obtained by implementing the output driver as a cascode differential amplifier. The logic circuitry implemented using a novel, DCAL (diode-clamped active-load) SCFL family, which is based on gate-width scaling rather than on absolute values, so that the on-chip logic voltage swing is less sensitive to process variations than conventional SCFL. A 60% improvement in noise margin is also obtained. To verify laser driving performance a back-to-back optical-fiber transmission experiment was performed, giving good optical eye diagrams at 2.5 Gb/s. The electrooptical interplay between laser-diode driver and laser-diode has been demonstrated using SPICE simulations     

具有连续自动温度补偿功能的10Gb/s光收发模块

设计并制作了一种10Gb/s光收发模块,在宽温度范围内能够保持稳定的光功率和消光比。基于背电流和光功率的换算比例,计算其偏置电流修正值和调制电流修正值,实现了光模块运行过程中激光器的工作参数可自动连续调节。通过高速电路信号仿真设计,解决了信号完整性、串扰和电磁兼容等问题。光模块收发通道可以独立工作,传输速率可达10Gb/s,实现了光模块高速率、高稳定性以及小体积设计,为甚短距离高速数据传输和处理提供了高可靠性的数据链接。     

A 1.25 Gbps DC-coupled laser diode driver with VBE compensation technique

A 1.25 Gbps integrated laser diode driver (LDD) driving an edge-emitting laser has been designed and fabricated in 0.35 μm BiCMOS technology. The IC can provide independent bias current (5-100 mA) with automatic power control, and modulation current (4-85 mA) with temperature compensation adjustments to minimize the variation in extinction ratio. This paper proposed an unique modulation output driver configuration which is capable of DC-coupling a laser to the driver at +3.3 V supply voltage; and combined a V_BE compensation circuit, the IC can operate at a wide temperature range (−40 to 85 °C) for date rates up to 1.25 Gbps. V_BE compensation technique is used to compensate for variation in V_BE over the operating temperature range so as to minimize the variations in rise and fall time of modulation output over temperatures.     

0.25μm CMOS工艺实现的3.125 Gb/s×12通道VCSEL驱动器阵列

本文介绍了一种利用0.25μm CMOS工艺实现的12通道垂直腔面发射激光器(VCSEL)阵列驱动器电路.该电路采用3.3V单电源供电,单通道最大输出调制电流超过30毫安,单通道工作速率达到3.125Gb/s,12个并行通道的总带宽为37.5Gb/s.