摘要:

An asymmetry in the output power and the low‐frequency noise emitted from the rear and front facets of index‐guided semiconductor lasers with a large percentage of optical feedback into the front facet is reported. Transitions from coherent to incoherent feedback‐induced properties by modulation of the feedback path length can be distinguished in the output power versus current (L‐I) curve. A cross‐over point is found only in the front facetL‐Icurve corresponding to a minimum in the noise. A model is presented which correctly describes the asymmetry between theL‐Icurve of the front and rear facets. It also predicts the observed cross‐over point in the front facetL‐Icurve.

ISSN:0003-6951    

DOI:10.1063/1.96707

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A fabrication technique based on reactive ion beam etching is presented for the formation of the facet mirrors on GaAs/AlGaAs lasers called pair‐groove‐substrate (PGS) multiquantum well lasers. Laser cavities with vertical and smooth walls are achieved with this etching technique by using a high‐temperature baked photoresist mask. PGS lasers with 200‐&mgr;m‐long etched cavities show a low pulsed threshold current of 29 mA and a high external differential quantum efficiency of 43%. The threshold current is comparable to those of cleaved lasers. Room‐temperature cw operation is easily realized in junction‐up mounting.

ISSN:0003-6951    

DOI:10.1063/1.96708

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Electrical pulses shorter than 0.6 ps were generated by photoconductively shorting a charged coplanar transmission line with 80 fs laser pulses. After propagating 8 mm on the line the electrical pulses broadened to only 2.6 ps.

ISSN:0003-6951    

DOI:10.1063/1.96709

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Fast recovery (<200 ps) of an optical gate at room temperature in a GaAs e´talon is observed by eliminating the top AlGaAs window and defining 9×9 &mgr;m2pixels. This recovery time is at least an order of magnitude shorter than that for previous e´talons consisting of AlGaAs/GaAs/AlGaAs heterostructures. The fast recovery is attributed to faster surface recombination of carriers at the GaAs‐dielectric mirror interface as compared to that at a GaAs‐AlGaAs interface.

ISSN:0003-6951    

DOI:10.1063/1.96710

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A new plastic optical fiber using pentafluoro trideutero styrene as a core has been prepared which enables stable transmission of near‐infrared (near‐IR) optical signals. Replacement of hydrogen in the core polymer with a combination of fluorine and deuterium effectively reduces molecular vibrational absorption from the near‐IR to the visible region. A 174 dB/km attenuation loss was obtained in the 850 nm region. Fluorination of aromatic hydrogen of styrene suppresses the water vapor absorption very effectively, and stable optical attenuation under high humidity is achieved.

ISSN:0003-6951    

DOI:10.1063/1.96711

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We have deposited ‘‘diamondlike carbon’’ films on various substrates using a new plasma assisted chemical vapor transport process in a high rf power density presssure ratio gas discharge. The films reported here exhibit the following properties: (1) high transparency for wavelengths greater than 300 nm; (2) an index of refraction of ∼2 at 850 nm; (3) a hardness between that of quartz and sapphire, increasing with ion energy bombarding the deposition surface; (4) strong adhesion to KBr, sapphire, and Si substrates; (5) high dielectric strength; (6) inertness to highly reactive chemicals.

ISSN:0003-6951    

DOI:10.1063/1.96712

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A simple model, using a quasi‐stationary, asymmetric, double probe theory, is presented to describe radio frequency planar glow discharge with a capacitively coupled excitation electrode. It reasonably agrees with available experimental results at frequencies lower than the ionic plasma frequency.

ISSN:0003-6951    

DOI:10.1063/1.96713

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Graphoepitaxy of Pt films on sawtooth profile gratings is realized. Gratings with 0.4 &mgr;m period are fabricated in (100)Si wafers using laser holographic lithography and Si anisotropic etching. Pt films evaporated at 200 °C on the gratings and annealed at 800 °C have (100) planes parallel to the substrate. From scanning electron micrograph it is found that the 100‐nm‐thick Pt film consists of crystallites embedded in the gratings. The grain size is about one grating period wide and 0.5–5 &mgr;m long. Continuous films with (100) orientation are produced after further deposition and annealing.

ISSN:0003-6951    

DOI:10.1063/1.96714

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Interactions of silicide films with undoped polycrystalline layers of Si grown by chemical vapor deposition at 630 °C were investigated by MeV He ion backscattering spectrometry, scanning electron microscopy, and transmission electron microscopy. For TiSi2, heat treatment in vacuum at temperatures above 850 °C results in erosion of the polycrystalline Si layer and growth of Si crystallites in the silicide film. The same phenomenon is observed for NiSi, Pd2Si, and CrSi2at temperatures above one‐half of melting point of the corresponding silicide.

ISSN:0003-6951    

DOI:10.1063/1.96715

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

High‐purity GaInP alloy was grown by chloride vapor phase epitaxy (Ga/In/PCl3/H2system) with two separate metal source regions. The alloy composition could be precisely controlled by using separate regions for Ga and In metals. From the photoluminescence and Hall effect analysis, epitaxial layers lattice matched to GaAs substrates showed high emission efficiency, the full width at half‐maximum of the free‐exciton luminescence was as narrow as 7.4 meV at 77 K (3.8 meV at 4.2 K), and the low impurity concentration was below 1.5×1015cm−3.

ISSN:0003-6951    

DOI:10.1063/1.96716

出版商:AIP    

年代:1986

数据来源: AIP