摘要:

We report a 50‐fold fiber‐grating pulse compression in the near‐infrared region. 100 ps (FWHM) pulses from a mode‐locked neodymium:yttrium aluminum garnet laser operated at 1.319 &mgr;m have been compressed into 2 ps pulses by using a 2‐km dispersion‐shifted fiber and a grating pair separated by 2.41 m in a double‐pass configuration. The novel feature of this demonstration is the use of dispersion‐shifted fiber (zero‐dispersion wavelength at 1.59 &mgr;m) for producing a linear chirp over most of the pulse and, thus, almost all the input power appears in the compressed pulse.

ISSN:0003-6951    

DOI:10.1063/1.96589

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The fabrication and performance characteristics of InGaAsP (&lgr;∼1.3 &mgr;m) ridge waveguide laser arrays are described. The ridges have variable spacing but are chosen to be of equal widths so that the propagation constants, which determine the emission wavelengths, of the individual emitters are equal. The lasers have threshold currents in the range 300–350 mA at 30 °C and have been operated to pulsed output powers of 600 mW/facet. The far field along the junction plane is single lobed with a width characteristic of a phase locked, diffraction limited beam. Measurements of cw emission spectrum also show emission in a single fundamental supermode.

ISSN:0003-6951    

DOI:10.1063/1.96590

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Double heterostructures consisting of InAs0.91Sb0.09active layers with Al0.5Ga0.5Sb cladding layers were grown by molecular beam epitaxy on GaSb substrates. Optically pumped laser emission at 3.9 &mgr;m was observed from 80 to 135 K with an exponentially dependent threshold withT0=17  K. At 80 K the threshold corresponds to an effective current of 4 kA/cm2. This value represents a significant reduction when compared with previous results. For a 1‐&mgr;m‐thick active layer the full angular width of the far field at the half intensity point normal to the junction is 40° and is in reasonable agreement with the width calculated from the guide and cladding refractive indices.

ISSN:0003-6951    

DOI:10.1063/1.96537

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Optical extraction efficiency from conventional lasers and amplifiers with nonsaturable intrinsic absorption is substantially below the maximum efficiency at absorption length products exceeding unity. This result is caused by the fact that high intensities in the amplifier cause saturation of gain but not absorption. In this letter, a new scalable amplifier concept is analyzed which maintains near maximum extraction efficiency as the laser length increases beyond absorption length products of unity.

ISSN:0003-6951    

DOI:10.1063/1.96538

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We have demonstrated the operation of an optical switch requiring less than 1 f J (<7000 photons) of incident optical energy. The switch operates at room temperature, is compatible with optical communication systems, and is cascadable because it has gain. The switching times (onandoff) are determined to be less than 1 ns. This device significantly advances the possibility for realization of high throughput optical signal processing and digital optical computing.

ISSN:0003-6951    

DOI:10.1063/1.96539

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

An acoustic source formed by pulsed laser irradiation has been used to investigate the piezoelectric and acoustoelectric effects within a cadmium sulphide detector. Analysis of detected waveforms has enabled the two effects to be identified. The resulting transducer combination has application to imaging systems, where phase insensitivity may be required.

ISSN:0003-6951    

DOI:10.1063/1.96540

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Characteristics in the motion of dislocations generated from scratches in GaAs doped with In at a concentration of 2×1020atoms/cm3are investigated and are compared with those in undoped GaAs. &agr; dislocations in In‐doped GaAs are found to be immovable under stress lower than 10 MPa in the temperature range 350–750 °C. Such immovability under low stress is not found for &bgr; dislocations in In‐doped GaAs and for both &agr; and &bgr; dislocations in undoped GaAs.

ISSN:0003-6951    

DOI:10.1063/1.96541

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Photoluminescence studies of Si+, S+, Se+, and Te+ion‐implanted GaAs made by molecular beam epitaxy were carried out at 2 K. A new emission denoted by [D] was commonly obtained at 1.408 eV. It was also found that the controversial near band‐edge emissions, ‘g’ and [g‐g], which were originally produced by the ion implantation of acceptor impurities, were not formed by donor ion implantation.

ISSN:0003-6951    

DOI:10.1063/1.97013

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Films of WSi2initially deposited in an amorphous form have been known to display an unexpected resistivity maximum when annealed at a temperature corresponding to the transition from the low‐temperature hexagonal structure to the high‐temperature tetragonal structure. It is shown that the resistivity maximum is due to an extremely high (5×106/cm) density of stacking faults. Thus, at least one of the scattering defects which contribute to the relatively high resistivity of WSi2films has been identified.

ISSN:0003-6951    

DOI:10.1063/1.96542

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Secondary grain growth in thin Au films on SiO2substrates is reported. Secondary grains have {111} texture which minimizes the surface energy. This indicates that surface energy anisotropy provides selectivity in the driving force for growth of secondary grains. In thin Au films on SiO2, surface‐energy‐driven secondary grain growth occurs at room temperature as soon as a film becomes continuous. This mode of grain growth is, most likely, responsible for the development of the frequently observed {111} deposition texture in thin Au films.

ISSN:0003-6951    

DOI:10.1063/1.96543

出版商:AIP    

年代:1986

数据来源: AIP