High-power 1.8-μm InGaAsP/InP lasers

Separately bounded InGaAsP/InP laser heterostructures with two stressed quantum wells emitting at a wavelength of 1.8 μm were obtained by metalorganic vapor-phase epitaxy. The laser diodes with a strip width of 100 μm provide for an output radiation power of 1.2 W in the continuous operation mode at a temperature of 20°C. A minimum threshold current density was 320 A/cm² and a differential quantum efficiency was η_d=28% for a Fabry-Perot resonator length of 1.4 mm. The internal optical losses in the laser heterostructure studied amounted to 5.6 cm^?1.     

Sub-micrometre distance measurements with a broadly tunable short-external-cavity InGaAsP/InP diode laser

Measurement of distance using a custom-designed, broadly tunable InGaAsP/lnP short-external-cavity diode laser is described. A tuning range of over 100 nm was achieved with the custom-designed laser in a diffractive optical element short external cavity. This tuning range made it possible to achieve a sub-micrometre resolution in measurement of distance with a single laser source for an interferometer. A non-linear, least squares fitting method was used to extract the displacement from the raw data. This fitting method showed a potential for extraction of accurate displacement in the presence of noise.     

InGaAsP／InP PFBH激光器

采用Ｎ－ＩｎＰ衬底研制ＩｎＧａＡｓＰ／ＩｎＰ激光器和ＤＦＢ激光器在国内已报导过多次，本文介绍用Ｐ－ＩｎＰ衬底研制ＩｎＧａＡｓＰ／ＩｎＰ平面埋层异质结构激光器和ＤＦＢ－ＰＦＢＨ激光器，同时利用晶体生长和晶向的依赖关系，改进埋区的结构，使器件最高激射温度大于１００℃。     

Mesastripe single-mode separately bounded lasers based on InGaAsP/InP heterostructures obtained by VPE of organometallic compounds

Mesastripe single-mode InGaAsP/InP laser diode heterostructures with an optical emission power of 200 mW in the continuous lasing mode at two wavelengths (1.3 and 1.55 μm) were obtained by metalorganic VPE. In the samples with a mesastripe contact width of W=5 μm, the single-mode lasing regime was observed in the entire range of pumping currents. For a cavity length of 1.0–2.5 mm, the threshold current densities varied within 450–600 A/cm². The differential quantum efficiency reached 30–40%. The internal optical losses in the mesastripe laser heterostructures are reduced to 7.7 cm⁻¹. The output power-pumping current characteristics of control samples remained unchanged upon testing for 1500 h at 50°C.     

Stress-induced defect migration in InP/InGaAsP double-heterostructure wafers

A low luminescence efficiency ring, concentric with the circular electrical contact, has been observed on p-InP and p-InGaAsP (λ = 1.1 μm) epitaxial layers using cathodoluminescence imaging. This low efficiency region is found to be due to contact alloying. A mechanism based on the thermal migration of a defect in the strain field produced by the p-contact is proposed.     

InGaAsP/InP long wavelength quantum well infrared photodetectors

High quality InGaAsP/InP MQWs structures, grown by solid source molecular beam epitaxy, with different doping concentrations in the wells were investigated. High doping concentrations benefits absorption but is not good for dark current. The photocurrent spectra and peak values are sensitive to applied voltage. The total photocurrent comes from the electrons excited to two excited states. The decrease of the photocurrent peak value at high voltage can be explained by the reduction of photogenerated electrons. The detectivity of the InGaAsP/InP QWIP measured at a bias of − 2.5 V at 20 K is greater than , which is comparable to the GaAs/AlGaAs QWIPs.     

ESD induced degradation mechanisms of InGaAsP/InP lasers

The sensitivity of InGaAsP/InP buried crescent lasers to ESD phenomena was deeply analysed, starting from the need to explain and prevent sudden failures during equipment manufacturing and test. Failure analysis allowed us to localize the degradation, which can be explained by means of a simple phenomenological model; finally a physical model was implemented trying to correlate the results of the failure analysis with the proposed failure mechanism.     

LPE growth of InP/InGaAsP/InP heterostructures and separate preparation of high-temperature solutions

We describe a process for separate preparation of high-temperature solutions, which includes a prolonged preannealing (synthesis) at elevated temperatures. This process enables liquid phase epitaxy (LPE) of InGaAsP with highly reproducible physical properties (layer thickness, photoluminescence wavelength, and lattice parameter) and electrical characteristics (current-power curve, dark current, output power, emission wavelength, and threshold and working currents). Using this process, InP/InGaAsP/InP heterostructures can be grown by LPE in a wide temperature range (480–680°C) with highly reproducible parameters, for both photodetectors and light-emitting devices. An original LPE process is proposed which takes advantage of the separate preparation and pouring of high-temperature solutions with the use of graphite equipment.     

InGaAsP/InP有源时分光子交换器件

自行设计并研制成功了两种有源时分光子交换器件：ＩｎＧａＡｓＰ／ＩｎＰ ＥＭＰＢＨ双稳激光器ＩｎＧａＡｓＰ／ＩｎＰ ＭＱＷ ＤＣＰＢＨ双稳激光器，对这两种器件的部分性能作了简要报道。     

The properties of InGaAsP/InP heterolasers with step-divergent waveguides

InGaAsP/InP laser heterostructures with step-divergent waveguides and two stressed quantum wells were obtained by metalorganic VPE. The lasers emitting at 1.55 μm provide for an intrinsic quantum yield of η_i=85%. An optical power of 5.2 W in the continuous operation mode was achieved at a laser diode temperature of 10°C. The internal optical losses in the laser heterostructure studied amount to 3.6 cm⁻¹, which is comparable with the level of losses in similar structures with uniform divergent waveguides.     

InP/InGaAsP异质结ICP刻蚀表面损伤

本文详细研究了采用Cl_2/H_2刻蚀气体时,ICP刻蚀系统对InP/InGaAsP材料表面损伤的影响。通过设计特殊结构的InP/InGaAsP多量子阱结构,测量刻蚀区域及非刻蚀区域的光荧光强度的变化,并结合高斯深度分布模型对刻蚀损伤进行定量研究。详细研究ICP刻蚀系统中的压强、ICP功率、RF功率以及Cl_2/H_2刻蚀气体组分对损伤程度的影响。基于这些结果优化得到一组低损伤参数,最终实现刻蚀损伤深度小于16nm。     

10×10InGaAsP/InP阵列波导光栅器件的研制

研制了脊形波导结构的10×10InGaAsP/InP阵列波导光栅器件(AWG),并采用掺铒光纤放大器(EDFA)作宽带光源测量了AWG的近场图以及分光特性。     

Gradient tuning of the direction of emission from InGaAsP/InP heterolasers

A new acoustooptical effect in laser heterostructures is revealed, according to which the laser emission direction is modulated by alternating strain that is induced in the laser structure by an external ultrasonic wave. An important feature of the observed phenomenon is that the amplitude of modulation increases with the frequency of the ultrasonic wave.     

Two-section InGaAsP/InP Fabry-Perot laser with a 12 nm tuning range

Wavelength tuning over a 12 nm range is obtained for a two-section InGaAsP/InP Fabry-Perot laser (λ=1.55 μm). The method used to vary the gain profile of the laser allows one to predict the range of possible wavelength tuning. Pis’ma Zh. Tekh. Fiz. 23, 10–15 (March 26, 1997)     

Gain measurements of Fabry-Perot InP/InGaAsP lasers using an ultrahigh-resolution spectrometer

Measurements of the optical gain in a semiconductor laser using a 20 MHz resolution optical spectrum analyzer are presented for what is believed to be the first time. The high resolution allows for accurate gain measurements close to the lasing threshold. This is demonstrated by gain measurements on a bulk InGaAsP 1.5 microm Fabry-Perot laser. Combined with direct measurement of transparency carrier density values, parameters were determined for characterizing the gain at a range of wavelengths and temperatures. The necessity of the use of a logarithmic gain model is shown.     

Low loss high mesa optical waveguides based on InGaAsP/InP heterostructures

Low loss high mesa optical waveguides were fabricated on InGaAsP/InP heterostructures by utilizing inductively-coupled-plasma reactive ion etching (ICP-RIE) and electron beam lithography technique. The fabrication process was optimized by measuring sidewall roughness of deep-etched waveguides. Atomic force microscope loaded with carbon nanotude was used to obtain three-dimensional image of the etched sidewall of waveguides. The obtained statistical information such as rms roughness and correlation length was used to theoretically calculate scattering loss of waveguides. Several waveguides with different number of sharp bends and the length were fabricated and their propagation losses were measured by modified Fabry-Perot method. The measured propagation losses were compared with theoretically calculated losses.     

Material-selective etching of InP and an InGaAsP alloy

Wet chemical etchants are inexpensive and can be employed easily in device fabrication. Material-selective etchants extend the design flexibility for devices with heterostructures. Several etchants on (100) InP and LPE-grown (100) InGaAsP are studied with emphasis on smooth crystal surfaces and well-defined mesa-structures by use of photoresist. The best results are obtained with the system glycerine: HCl HClO₄ for preferential attack of InP and with the system H₂O H₂SO₄ H₂O₂ for preferential etching of InGaAsP. Detailed information is given on the etching solutions investigated, on the etching conditions and the etching rates of the most useful etchants.     

Growth and characterization of InGaAsP lattice-matched to InP

The development of InGaAsP lattice-matched to InP as a suitable material for a range of electronic devices is reviewed. Currently accepted values of fundamental material parameters such as lattice constant, energy band-gap and effective mass as a function of composition are presented. The various growth techniques are discussed with particular emphasis given to the liquid phase epitaxy (LPE) method which has emerged as the most popular. Details of the determination of the liquidus and solidus phase diagrams both theoretically and experimentally are given and a comparison of the two is carried out. The problems of doping control and lattice matching are discussed. The other less widely-used growth methods, vapour phase epitaxy (VPE) and molecular beam epitaxy (MBE), are also outlined. The development of optical sources (lasers and LED's) and photodetectors for optical-fibre communication systems is presented with particular attention being paid to the device technology. The latest performance figures in this rapidly moving area are reviewed. Prospects for the use of this material in non-optical applications are discussed in terms of its transport properties and device technology for applications in microwaves and high-speed logic.     

Orthogonal linear polarization tunable-beat ring laser with a superluminescent diode

An orthogonal linear polarization operated ring laser with a superluminescent diode has been demonstrated to generate a tunable optical beat signal. The ring cavity contains a superluminescent diode as the optical gain medium, Faraday rotators, and a variable phase retarder (Babinet-Soleil compensator). By controlling the retarder, we changed the beat frequency in the range from a few tens of megahertz to 100 MHz.     

Sinusoidal wavelength-scanning interferometer with a superluminescent diode for step-profile measurement

In sinusoidal phase-modulating interferometry an optical path length (OPD) larger than a wavelength is measured by detection of sinusoidal phase-modulation amplitude Z(b) of the interference signal that is produced by sinusoidal scanning of the wavelength of a light source. A light source with a large scanning width of wavelength is created by use of a superluminescent laser diode for the error in the measured value obtained by Z(b) to be smaller than half of the central wavelength. In this situation the measured value can be combined with a fractional value of the OPD obtained from the conventional phase of the interference signal. A sinusoidal wavelength-scanning interferometer with the light source measures an OPD over a few tens of micrometers with a high accuracy of a few nanometers.