摘要:

We report a novel electrolytic process that is used to fabricate reproducible, low loss, single mode waveguides. By precisely controlling the current pumped through high purity Ag and Pt electrodes in molten NaNO3, as well as its duration, a high degree of accuracy over the release and hence the control of Ag+concentration is achieved. The inherent capability of the process to generate very low level of silver ion concentration with high precision implies much higher time of diffusion, thus removing the time criticality factor faced by the existing processes while fabricating single mode waveguides.

ISSN:0003-6951    

DOI:10.1063/1.95137

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Chirping in coupled‐cavity lasers is studied experimentally and theoretically. Using a conventional and a cleaved‐coupled‐cavity (C3) laser obtained from the same wafer, we find that the chirp for a C3laser is typically reduced by a factor of 2. A simple rate equation model is presented to account for reduced chirping. Mode selectivity arising from the cavity coupling is incorporated through wavelength‐dependent cavity‐loss variations.

ISSN:0003-6951    

DOI:10.1063/1.95138

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

A ‘‘thermal fixing’’ process that dramatically reduces the photorefractive susceptibility of Ti‐indiffused LiNbO3channel waveguides has been demonstrated. Guided‐wave Mach–Zehnder interferometric modulators were used to characterize the photorefractive susceptibility of the waveguides. These devices were evaluated before and after the thermal fixing process which was seen to be erasable, reproducible, and long‐lived. Photorefractive effects were reduced ten times for waveguide operation at &lgr;=0.46 &mgr;m and more than 100 times for operation at &lgr;=0.85 &mgr;m.

ISSN:0003-6951    

DOI:10.1063/1.95139

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

We demonstrate that applying optoelectronic feedback to a high‐speed, self‐pulsing semiconductor laser is an effective and practical means of generating picosecond optical pulses (∼10–20 ps) at a very high repetition rate, between 1 to 5 GHz, which can be electrically tuned. The optical pulses are very stable both on a short term basis with a frequency stability of one part in 105, and on the long term basis as a result of the absence of critical optical alignment. This laser system is potentially very useful in high‐speed electro‐optic signal processing, optical multiplexing, or laser ranging.

ISSN:0003-6951    

DOI:10.1063/1.95140

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

We describe the analysis and operation of an improved actively mode‐locked,Q‐switched continuously pumped neodymium:yttrium aluminum garnet laser. Basically the picosecond laser has been modified by a substitution of the classical output mirror by a convenient Fabry–Perot resonator which is used as the reflective element in order to provide an efficient reshaping of the picopulses. Instead of providing transform limited pulses with 100‐ps duration at 1‐MW peak power, our system is able to deliver sharper picopulses (18 ps) without significant loss in the overall efficiency. Besides obvious basic research applications, this low cost, easy to do modification may turn out to be extremely useful whenever laser implants and material cutting are concerned.

ISSN:0003-6951    

DOI:10.1063/1.95141

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Transient characteristics of x‐ray line radiation from high density plasmas in an ionizing phase are computationally shown in the picosecond region by solving coupled rate equations. Many atomic processes associated with x‐ray radiation are found to affect temporal changes of x‐ray intensities and, especially, the x‐ray intensity ratios. It is pointed out that in the evaluation of electron temperatures in transient plasmas, undesirable errors are apt to be brought about by usual conventional methods based on computations in which steady state equilibrium is assumed.

ISSN:0003-6951    

DOI:10.1063/1.95142

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

A plasma etching reactor is described which associates surface magnetic confinement, microwave discharge, and independently controlled substrate biasing. Preliminary measurements show that the reactor produces reactive plasmas allowing anisotropic fine line etching at low ion energy.

ISSN:0003-6951    

DOI:10.1063/1.95143

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

A strong correlation between a silicon‐rich interface in plasma deposited silicon nitride films with an initial transient phenomena during the plasma enhanced chemical vapor deposition process has been verified using optical emission techniques, plasma voltage potential (Vp) measurements, and Auger depth profile analysis. The data suggested that the silicon‐rich interface may be an intrinsic property of all plasma deposited films examined. This observation was found to be independent of tool type. However, it is possible to reduce the silicon‐rich interface thickness in plasma deposited films by shortening the transient time with judicious choice of tool and deposition conditions.

ISSN:0003-6951    

DOI:10.1063/1.95136

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

The adhesion of thin metallic films to silicon substrates is shown to improve following irradiation with a flux of either 21.2‐eV (He I) 10.2‐eV (H Lyman &agr;) photons. The improved adhesion is similar to that found following MeV energy ion irradiation and keV energy electron irradiation, adding support to the view that electronic excitation and/or ionization and precursors to the stronger bonding configuration.

ISSN:0003-6951    

DOI:10.1063/1.95144

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

When MoSi2films on silicon are exposed to oxidizing ambients, a continuous layer of SiO2grows on the silicide surface. However, when the presence of oxygen impurities exceeds 2 at. % at the silicon‐MoSi2interface, metal‐rich silicide phases form. The coexistence of these phases and the absence of metal oxides are explained by considering both the oxidation kinetics and the ternary phase diagram of the Mo‐Si‐O system.

ISSN:0003-6951    

DOI:10.1063/1.95145

出版商:AIP    

年代:1984

数据来源: AIP