摘要:

An experimental study of the coupling of diode laser arrays to various photorefractive phase conjugate mirrors is presented. We demonstrate frequency locking of arrays as well as the control of their emitted light patterns.

ISSN:0003-6951    

DOI:10.1063/1.97832

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Relative intensity noise (RIN) from 1.3 &mgr;m InGaAsP vapor phase regrown buried heterostructure diode lasers with cavity lengths of 100–300 &mgr;m and resonant frequencies exceeding 15 GHz is measured for the first time over the 2.5–18 GHz frequency range. We show that the RIN decreases by nearly 8 dB as the cavity length increases from 100 to 300 &mgr;m, and that the RIN is also reduced by lowering the activep‐doping concentration. The measured RIN is in excellent agreement with the expression derived from the laser rate equations.

ISSN:0003-6951    

DOI:10.1063/1.97833

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The temperature dependence of threshold current in graded‐index, separate‐confinement‐heterostructure, single quantum well lasers has been investigated and analyzed. The conventional parameter used to describe this temperature dependence,T0, is measured and shown to increase with cavity length. The temperature dependences of the loss coefficient &agr; and the differential gain &bgr; have also been measured. Both parameters decrease linearly with temperature in the range 20–70 °C. Competition between &agr;(T) and &bgr;(T) is shown to account for the dependence ofT0on cavity length and to suggest guidelines for designing highT0lasers.

ISSN:0003-6951    

DOI:10.1063/1.97834

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The bistable switching between the TE and TM modes in semiconductor lasers has been analyzed using the rate equations. The condition of bistability has been determined using linear and nonlinear gain constants. The observed bistable switching behavior can be explained by a numerical simulation.

ISSN:0003-6951    

DOI:10.1063/1.97835

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The linewidth enhancement factor &agr; in an InGaAsP/InP multiple quantum well (MQW) laser has been determined from the spontaneous emission spectra below threshold. It is demonstrated that the measured value of &agr; in the MQW laser is appreciably smaller than that in a conventional double heterostructure laser as expected from theoretical calculations.

ISSN:0003-6951    

DOI:10.1063/1.97836

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

An approximate method is proposed to calculate the pole figure diagrams based on the elastic anisotropy measured by ultrasonic velocity experiments. An example is taken from the surface texture of rolled plates of aluminum alloy 7075‐T651, for which the angular dependence of the Rayleigh wave is measured in the rolling plane and analyzed to obtain the expansion coefficients of orientation distribution function. The ultrasonic pole figures are favorably compared with the conventional x‐ray pole figures, both demonstrating a single texture centered over (001)[110] orientation.

ISSN:0003-6951    

DOI:10.1063/1.97837

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

It is demonstrated that heat treatment of a LiNbO3plate at temperatures somewhat lower than the Curie point causes a ferroelectric domain inversion, thereby yielding an inversion layer useful for various piezoelectric devices. The dependences of the inversion layer thickness on the heat treatment conditions, such as temperature, time, and atmosphere, are experimentally examined. The results show that the domain boundary appears to stop at the median plane of the plate finally. The possible mechanism of the domain inversion is also discussed.

ISSN:0003-6951    

DOI:10.1063/1.97838

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The 1/fnoise of polycrystalline gold films (5 &mgr;m wide and 0.5 &mgr;m thick) was found to decrease in the presence of hydrogen, to a level comparable with that in a single‐crystal gold film. Additionally, hydrogen was found to segregate to the metal‐substrate interface. On the basis of these results and recent evidence in the literature, we propose that hydrogen interacting with interface defects is responsible for both the observed 1/fnoise decrease and the previously reported electromigration enhancements.

ISSN:0003-6951    

DOI:10.1063/1.97839

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We describe an approach based on high‐resolution transmission electron microscopy (HRTEM), which is capable of directly and sensitively revealing the atomic configuration at compound semiconductor/semiconductor interfaces, and thus show that interfaces normally regarded as atomically smooth can contain significant roughness. Our technique establishes that HRTEM can simultaneously provide chemical and structural information on an atomic scale.

ISSN:0003-6951    

DOI:10.1063/1.97840

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Polyacrylonitrile films have been spin cast and pyrolyzed to produce thin (500–1500 A˚) carbon films. These films have higher electrical conductivities than films produced by other methods at similar temperatures. The conductivity can be varied by at least four orders of magnitude by changing the pyrolysis temperature. Ultraviolet, infrared, and Raman spectroscopies were used to investigate the chemical structure of the films during different stages of processing.

ISSN:0003-6951    

DOI:10.1063/1.97841

出版商:AIP    

年代:1987

数据来源: AIP