Analysis and optimization of an InGaAsP/InP waveguide variable optical attenuator

An InGaAsP/InP waveguide variable optical attenuator (VOA) is proposed in this paper. The device consists of straight input and output waveguides and an S-bend waveguide. An electrode is deposited on a portion of the waveguide to form an active region so that its refractive index can be modified by a current injection, resulting in the variation of the transmitted optical power. The beam propagation method is employed in the numerical simulation and the device structure is optimized using a genetic algorithm. The optimized VOA has a low excess loss (<1 dB) and a large dynamic range of about 40 dB.     

InGaAsP/InP evanescent mode waveguide optical isolators and their application to InGaAsP/InP/Si hybrid evanescent optical isolators

We theoretically investigated InGaAsP/InP evanescent mode waveguide optical isolators and proposed their application to InGaAsP/InP/Si hybrid evanescent optical isolators. InGaAsP/InP evanescent optical isolators are composed of semiconductor optical amplifier (SOA) waveguides having InGaAsP multiple quantum well (MQW) active layer and upper InGaAsP waveguide layer with ferromagnetic layer. Optical isolation is obtained for evanescent optical mode in the InGaAsP waveguide layer. InGaAsP/InP/Si hybrid evanescent optical isolators are theoretically proposed based on the idea of InGaAsP/InP evanescent optical isolators. InGaAsP/InP/Si hybrid evanescent optical isolators are composed of ferromagnetic metal loaded silicon evanescent waveguides with wafer-bonded InGaAsP/InP optical gain material. The optical isolation and propagation loss are discussed with the structure of silicon evanescent waveguides, and optical isolation of 8.0 dB/mm was estimated. The concept of semiconductor evanescent mode optical isolators is feasible with InP based photonic integrated circuits and advanced silicon photonics.     

Single-step growth of InGaAsP/InP laser array on patterned InP substrate

Arrays of five InGaAsP/InP single mode junction-defined buried stripe heterostructure lasers are described. The laser arrays were grown on multi-channeled InP substrate by single-step liquid phase epitaxy. The buried double heterostructure and the lateral current confining structure were formed in the same growth process. InGaAsP layer growth is dominated by the preferred orientation, with (1 0 0) growth favored over other directions. As a result of low-temperature single-step growth, the device yield is high. These laser arrays are characterized by output power close to 0.6 W, high quantum efficiency, symmetrical far-field patterns and excellent linearity of the light–current curve. Stable single transverse mode operation obtained up to 600 mW emitted power.     

场助InGaAsP/InP异质结半导体光电阴极的研究

本文通过对InGaAsP/InP场助异质结半导体光电阴极的材料生长、场助肖特基结的制备及阴极激活等工艺的系统研究,研制出具有较高光谱响应的半导体光电阴极,生长出优于文献报道的晶格失配率标准的材料,得到相当80年代国际水平理想因子值的场助肖特基结,用实验数据介绍提高量子效率数量级的方法和条件.研究结果表明场助异质半导体光电阴极是在红外波段很有潜力的光电发射体.     

Acousto-electron interaction in InGaAsP/InP laser heterostructures

The frequency modulation of the heterolaser radiation under the ultrasonic strain has been found out. The dynamic and static analysis of the spectral parameters change caused by the alternating strain has been fulfilled. A model is proposed for describing the experimental data, and their theoretical analysis is performed. It is demonstrated that the acousto-electron interaction is dominant under the action of surface waves in InGaAsP/InP laser heterostructures.     

Integrated MQW intermixed InGaAsP/InP waveguide photodiodes

A multi-wavelength Quantum well (QW) waveguide photodiode (PD) have been designed for Coarse Wavelength Division Multiplexing (CWDM) systems in which spatial tailoring of the bandgap with post growth F implanted QW intermixing of InGaAsP/InP multi QWs for the integration have been considered. Two separate structures with different composition but same well widths are necessary to detect all CWDM wavelengths. For In_0.5995Ga_0.4005As_0.8521P_0.1479 well there is a 12 channel coverage from 1,270 to 1,490 nm and for the In_0.5540Ga_0.4460As_0.9489P_0.0511 well the 14 channel spans from 1,350 to 1,610 nm. A carrier tunneling time of 20 ps along with the transit time limited bandwidth of 86 GHz gives a 3 dB bandwidth of 41 GHz by optimizing the i-MQW thickness and dopant concentration of the different layers of the waveguide. A maximum efficiency of 22% with insertion loss of 0.4–23 dB has been obtained.     

Acoustoelectronic interaction in InGaAsP/InP laser heterostructures

The dynamics of change in the spectral characteristics of the emission from a laser heterostructure due to an alternating strain induced by a surface acoustic wave is investigated. The spectral distributions of the laser radiation intensities are analyzed with the aim of elucidating the mechanisms responsible for the interactions occurring in the laser heterostructure. A model is proposed for describing the experimental data, and their theoretical analysis is performed. It is demonstrated that the acoustoelectronic interaction is dominant under the action of surface waves. The deviation of the observed frequency modulation of radiation is determined from a comparison of the theoretical calculations with experimental data.     

Modal properties of all-active InGaAsP/InP microring lasers

An experimental investigation of the multimode dynamics of 1.55 μm-InGaAsP/InP microring lasers is demonstrated. Different operation regimes are observed, bidirectional multimode, unidirectional single mode, bidirectional single mode and mode-hopping. The extent of each of the above operation regimes is examined with respect to the ring current level, bus waveguide reflectivity and ring radius. The back-reflections generated from the bus waveguide facets are indirectly controlled via the bus waveguide current. In order to clarify the physical mechanisms beyond experimental results, a multimode model based on the rate equation approximation is utilized. The experimental results are in good agreement to those predicted by the multimode model.     

Miniature InGaAsP/InP phase modulator for integrated opto-electronics

Abstract

Miniature, etching ridge InGaAsP/InP Phase Modulator with highly efficient phase shifting efficiency of 60°/V.mm and 43°/V.mm for TE and TM modes, respectively, and 3 dB bandwidth of 650 MHz at 1.52 μm are reported. It is well suited for integrated opto-electronics. Some functions depending on bandwidth of the devices are discussed.     

Opto-electronic integrated circuits using the InGaAsP/InP system

Recent developments in opto-electronic integrated circuits (OEICs) using the InGaAsP/InP system which is monolithically integrated with opto-electronic and electronic devices are discussed. The technological problems for the development of the OEICs are explained by reviewing recent developments in OEICs.     

Carrier dynamics in strain-induced InGaAsP/InP quantum dots

Carrier dynamics of strain-induced InGaAsP/InP quantum dots (QDs) is investigated. In this structure, self-assembled InAs islands on the surface act as stressors and create a lateral confinement potential in the near surface InGaAsP/InP quantum well. Photoluminescence (PL) measurements reveal that decreasing the distance from the QD to the surface significantly diminishes the QD–PL intensity, presumably due to surface states of the InAs islands. Moreover, time-resolved measurements show a faster decay of the QD–PL with decreasing distance. To analyze the carrier dynamics, rate equation model is applied and surface state-related transitions are taken into account. The model is found to agree with measurements, and thus provides a possible explanation for the observed temporal behavior of the carriers.     

Miniature InGaAsP/InP phase modulator for integrated opto-electronics

Miniature, etching ridge InGaAsP/InP Phase Modulator with highly efficient phase shifting efficiency of 60°/V.mm and 43°/V.mm for TE and TM modes, respectively, and 3 dB bandwidth of 650 MHz at 1.52 μm are reported. It is well suited for integrated opto-electronics. Some functions depending on bandwidth of the devices are discussed.     

场助InP／InGaAsP／InP半导体光电阴极异质结能带的计算

采用双曲型的渐变函数,同时考虑加偏压时引起的阴极表面空间电荷区的变化,对场助InP/TnGaAsP/InP半导体光电阴极异质结的能带结构进行了详细的分析和计算,得到了在不同材料参数时,异质结能带结构的分布曲线.计算结果指出了达到理想的异质结传输效率时,发射层的厚度和掺杂浓度、吸收层的掺杂浓度、异质结界面处渐变区宽度以及场助偏压应满足的条件.它有助于场助半导体光电阴极的结构设计和材料参数的选择.     

Toward low-loss photonic crystal waveguides in InP/InGaAsP heterostructures

Line-defect photonic crystal waveguides exhibit severe propagation losses if they are implemented in semiconductor heterostructures with a weak refractive index contrast. We present, for what we believe is the first time, experimental structures for which we have evidence that fabrication imperfections are not the limiting factor in terms of propagation losses. We demonstrate a loss figure of 335±5 dB/cm, which is an improvement by a factor of about 2 with respect to state-of-the-art values. Simulations show that even lower losses can be obtained with different waveguide geometries. In other words, the dominant loss mechanism is related to the waveguide design, and losses are not expected to decrease upon further optimization of the fabrication process.     

Multiwavelength generation using an add-drop microring resonator integrated with an InGaAsP/InP sampled grating distributed feedback

A system of an add-drop microring resonator integrated with a sampled grating distributed feedback(SG-DFB) is investigated via modeling and simulation with the time-domain traveling wave(TDTW)method.The proposed microring resonator comprises a SiO_2 waveguide integrated with an In Ga As P/In P SG-DFB,and the SiO_2 waveguide consists of a silicon core having a refractive index of 3.48 and Kerr coefficient of 4.5 × 10~(-18)m~2∕W.The SG-DFB consists of a series of grating bursts that are constructed using a periodic apodization function with a burst spacing in the grating of 45 μm,a burst length of 5 μm,and 10 bursts across the total length of the SG-DBR.Transmission results of the through and drop port of the microring resonator show the significant capacity enhancement of the generated center wavelengths.The Q-factor of the microring resonator system,defined as the center wavelength(λ0) divided by 3dB FWHM,without and with integration with the SG-DFB is calculated as 1.93 × 105 and 2.87 × 10~5,respectively.Analysis of the dispersion of the system reveals that increasing the wavelength results in a decrease of the dispersion.The higher capacity and efficiency are the advantages of integrating the microring resonator and the In Ga As P/In P SG-DFB.     

布里渊-掺铒光纤随机光纤激光器输出特性分析

设计了一种基于受激布里渊散射和掺铒光纤混合增益的随机光纤激光器,该激光器选用两段长为20km的单模光纤组成全开放腔结构,利用单模光纤的瑞利散射提供随机光反馈.研究表明,固定布里渊泵浦波长和泵浦功率分别为1 550.00nm和2.19mW时,增加掺铒光纤泵浦功率,可以实现两个波长的随机激光输出,一阶和二阶受激布里渊散射光与布里渊泵浦光波长间隔分别约为0.088nm和0.174nm,产生一阶和二阶受激布里渊散射对应的掺铒光纤泵浦功率分别为190mW和370mW;当掺铒光纤泵浦功率为433mW时,激光器两端的最大输出功率为1.60mW和1.68mW.当掺铒光纤泵浦功率明显高于阈值功率时,获得的一阶和二阶随机激光输出稳定,3dB线宽约为0.022nm,峰值强度和位置基本不随时间而变化.     

Experimental study of stability properties of injection-locked InGaAsP/InP laser diodes

Single-mode operation of the laser is a basic condition in an optical wide-band transmission link. Lasers stabilized by injection locking showed excellent side-mode suppression. Slight detunings within the locking range between the master laser and slave laser caused by modulation, bias current variations or optical feedback led to unstable behaviour and disturbed the BER of a 1.12 Gbits^–1 transmission experiment via a 21-km single-mode fibre.     

All-optical tunability of InGaAsP/InP microdisk resonator by infrared light irradiation

We report the optical characterization of an InP structure constituted by waveguides coupled to microcavity disk resonators. The lateral waveguide confinement is obtained by deep reactive ion etching through the guiding layer. We demonstrate the possibility of tuning optically the resonance wavelength into the illuminating disk resonator. We obtained a blueshift of 3 nm by laser irradiation at 980 nm corresponding to a photoinduced change in the effective refractive index of 6 x 10(-3). The InP structure behaves as a tunable optical demultiplexer.     

Modeling of integrated extended cavity InP/InGaAsP semiconductor modelocked ring lasers

In this paper a model and simulation results of integrated semiconductor passively modelocked ring lasers are presented. The model includes nonlinear effects such as two-photon absorption and a non-linear refractive index, a logarithmic gain-carrier relation, and concentration dependent radiative and non-radiative carrier recombination rates. The optical bandwidth of the system is controlled by a digital filter. The model has been used to simulate two geometries of ring modelocked lasers. The first is a symmetric design, where the two counter propagating pulses in the cavity experience the same amplification and absorption. The second is an asymmetric design where the differences for the two directions of pulse propagation are maximised. Simulation results show that a symmetrical cavity shows a several times wider window for its operating parameters for stable modelocking.