摘要:

We describe a new method for measuring group‐delay differences between the modes of an optical fiber of the order of 1 psec. This is accomplished by Fourier analyzing the intensity output of the fiber, which is fed with a quasimonochromatic signal whose frequency is linearly modulated in time. We present the results of an experiment, in which time delays of the order of 10 psec have been measured. This confirms the potential of the method for measuring dispersion in optical fibers.

ISSN:0003-6951    

DOI:10.1063/1.88406

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

The spectral response of silicon solar cells has been studied under different conditions of excitation. The photocurrent variations are not linear with incident flux, and the minority‐carrier diffusion length increases under solar illumination because of trap saturation. It is thus possible to fabricate efficient solar cells with a lower‐quality material.

ISSN:0003-6951    

DOI:10.1063/1.88407

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

Integrated structures consisting of a double‐heterostructure GaAs‐AlGaAs etched‐mesa Fabry‐Perot laser coupled to a high‐purity GaAs waveguide have been fabricated and tested. Room‐temperature threshold current densities as low as 7.5 kA/cm2for 1‐&mgr;m‐thick active layers were measured.

ISSN:0003-6951    

DOI:10.1063/1.88408

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

Xenon with 0.10–4% Br2was excited by an e‐beam device over the range 10–3000 Torr. Stimulated emission was observed on the transition XeBr*→Xe+Br+h&ngr; (281.8 nm). Proof of laser emission and mechanistic details are discussed.

ISSN:0003-6951    

DOI:10.1063/1.88409

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

Liquid phase epitaxial (LPE) In1−x′Gax′P1−z′Asz′/In1−xGaxP1−zAsz/In1−@qLx′Gax′P1−z′Asz′(x′∼0.66,z′∼0.005;x∼0.71,z∼0.10) double‐heterojunction laser diodes that operate in the yellow at relatively low current densities (J<104A/cm2, &lgr;∼5850 A˚, 77 °K) are reported. The lattice‐matched LPE quaternary growth process, employing GaAs1−yPysubstrates, and the double‐heterojunction laser diode properties are described.

ISSN:0003-6951    

DOI:10.1063/1.88410

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

Theoretical and experimental results on new guided‐wave electro‐optic devices for ultrafast optical deflection, switching, and modulation are presented. The devices utilize simple electrode arrangements consisting of a small number of tilted electrodes which effectively simulate prism structures in electro‐optic waveguides. Devices using single‐modeY‐cut LiNbO3outdiffused waveguides have demonstrated excellent performance figures: nine beam positions (channels) per unit at a driving voltage of 8 V per beam position, −0.5 dB optical insertion loss and cross talks between adjacent channels varying from −13.5 to −9 dB. The new devices are shown to be capable of performing optical multiport beam deflection/switching and modulation at very low driving voltages and at ultrafast speeds because of their very small capacitances, and are, therefore, highly useful for future wide‐band fiber and integrated optic systems.

ISSN:0003-6951    

DOI:10.1063/1.88411

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

One of the difficulties in integrated optics is to form passive and active devices of different materials on a common substrate. We have solved part of the difficulty by introducing a technique of isolating low‐index devices from a high‐index substrate. We also report novel metal‐clad optical components which can be formed on any substrate.

ISSN:0003-6951    

DOI:10.1063/1.88412

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

Transport measurements were performed on thin films of Si3N4deposited on Si using carrier injection from low‐energy corona ions and a shallow junction detector. Large hole conduction is found for both corona polarities. Examination of the electronic structure of Si3N4by x‐ray photoemission spectroscopy (XPS or ESCA) reveals one broad structure 10 eV wide (FWHM) at the top of the valence bands which results from the bonding of the Si 3s, Si 3p, and N 2porbitals. This finding is consistent with the hole conduction we observe. The XPS results are compared with those from amorphous SiO2. The tops of the valence band of Si3N4and SiO2are found to lie 1.5±0.2 eV and 4.5±0.2 eV, respectively, below the Fermi level of a thin overlayer of gold.

ISSN:0003-6951    

DOI:10.1063/1.88413

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

This letter reports on the finding that holes are more mobile than electrons in chemically vapor deposited (CVD) Si3N4. MIS structures with Si3N4films as the insulating layers are used in the experiments. Holes are shown to be electrically injected from the silicon into the insulator when the aluminum‐gate electrode is pulsed negative, and electrons when pulsed positive, with subsequent trapping in the nitride. The centroid of the trapped‐hole distribution, X¯h, and that of the trapped‐electron distribution, X¯e, as functions of the voltage pulse amplitude and duration are measured. The ratio of X¯h/X¯eincreases with the amplitude of the pulse and its duration, where the centroids are referenced from the injection source, and exceeds 3 when the hole distribution spans the entire nitride thickness. Data suggest that hole traps are perhaps shallower than electron traps, hence the enhanced hole conduction in the silicon nitride.

ISSN:0003-6951    

DOI:10.1063/1.88414

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

The domain wall velocity in YFeO3and TbFeO3single‐crystal platelets is measured by the bubble‐collapse method. Though weak knees like saturation occur at 4800, 8000, and 14 000 m/sec, the wall velocity in YFeO3increases nearly linearly with increasing drive field up to 25 000 m/sec at a drive field of 370 Oe. The velocity in TbFeO3increases linearly up to 3000 m/sec (600 Oe). A mechanism quite different from that in garnet films appears to be operative in orthoferrites.

ISSN:0003-6951    

DOI:10.1063/1.88415

出版商:AIP    

年代:1975

数据来源: AIP