摘要:

Optical gain characteristics of an Er3+‐doped silica fiber have been studied by end pumping with a 1.48 &mgr;m InGaAsP high‐power laser diode. A gain as high as 12.5 dB was obtained for an absorbed pump power of 16 mW with a 3‐m‐long fiber. By constructing an Er3+fiber ring cavity with a 3 dB single‐mode fiber coupler, we have obtained continuous wave laser oscillation at a wavelength of 1.553 &mgr;m.

ISSN:0003-6951    

DOI:10.1063/1.101448

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Superluminescent diodes with high output power (10 mW at 175 mA), wide spectral width (28 nm), low spectral modulation depth (<15%), wide frequency modulation bandwidth (570 MHz), and high single‐mode fiber coupling efficiency (40%) are reported. The structure is based on a buried crescent laser structure with an antireflection coating and a ‘‘short‐circuit’’ absorber to suppress lasing.

ISSN:0003-6951    

DOI:10.1063/1.100992

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

We report the first demonstration of an optically controlled absorption modulator based on state filling in a periodically doped InxGa1−xAs/GaAs multiple quantum well structure. Differential absorption of approximately 104cm−1is observed in the quantum wells of our test structure at saturation pump powers. Photoluminescence and time‐resolved modulation measurements confirm the predicted behavior of carrier recombination and give a measure of enhanced carrier lifetime of approximately 1 ms. These initial results show the potential for developing these structures into optically addressed spatial light modulators.

ISSN:0003-6951    

DOI:10.1063/1.100993

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Low‐threshold arrays of GaAs/AlGaAs patterned quantum well semiconductor lasers were grown by molecular beam epitaxy on periodically corrugated substrates. Uncoated arrays of ∼14 lasers operated with threshold curents of 3.6 mA per laser and emitted up to 375 mW from a single facet under pulsed conditions. The array lasers were not phase locked because of the tight optical confinement in each array channel. A red shift of 300 A˚ (55 meV) was observed in the emission wavelength of the patterned array compared to that of nonpatterned lasers made on the same substrate. The red shift results from migration effects in the growth on the nonplanar surface, which leads to thicker quantum well active regions at the array channels. This effect illustrates the usefulness of the growth of quantum well heterostructures on nonplanar substrates for lateral band‐gap engineering.

ISSN:0003-6951    

DOI:10.1063/1.100994

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

We describe coherent microwave transient spectroscopy experiments using picosecond optoelectronic integrated antennas. The effectiveness of the experimental setup for the measurement of the loss and dispersion properties of materials in the 10–125 GHz range is characterized using microwave filters of predictable behavior. We also present measurements of the absorption coefficient and refractive index of fused silica over this frequency band.

ISSN:0003-6951    

DOI:10.1063/1.101554

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The infrared absorption of Ir and IrSi thin films on Si substrates has been determined by transmission and reflection measurements over the wavelength range 2.5–25 &mgr;m. Detailed analysis of the dependence of absorption at 4 &mgr;m on film thickness indicates that a thin boundary layer with lower absorption than Ir is present at the Ir/Si interface and that such a layer with lower absorption than IrSi is present at the IrSi/Si interface. The existence of the boundary layers has been confirmed by the detection of oxygen at the interfaces by Auger analysis. Absorption and Auger measurements give no evidence of boundary layer formation at Pt/Si or PtSi/Si interfaces.

ISSN:0003-6951    

DOI:10.1063/1.100995

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Second‐harmonic generation of tunable CO2laser radiation is reported and analyzed in ZnGeP2both by angular and temperature tunings. Temperature tuning can thus be advantageously employed in this crystal for nonlinear devices.

ISSN:0003-6951    

DOI:10.1063/1.101449

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

An electronic lens is developed for controlling the focus position of an optical beam without mechanical movement. The lens utilizes the dependence of the lateral index profile on carrier concentration profile in the waveguide layer. The lens is integrated with a diode laser by the cleave‐couple technique, and the control of the focus position of the output beam of this device is demonstrated.

ISSN:0003-6951    

DOI:10.1063/1.100996

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The collisionless space‐charge sheath of a capacitivelyc oupled rf discharge is investigated in the frequency regime &ohgr;pi≪&ohgr;≪&ohgr;pe. Assuming Boltzmann distributed electrons and starting from an existing charge exchange model of the presheath a self‐consistent analysis is presented.

ISSN:0003-6951    

DOI:10.1063/1.100997

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

A new ion beam annealing phenomenon which occurs during room‐temperature irradiation of Si is discussed. The interaction of high‐energy ions with different damage morphologies is shown to depend on the detailed nature of the damage. This interaction leads to annealing when the damage consists only of simple types of defects, while irradiation of more complex damage morphologies can result in additional damage growth. A model is proposed which qualitatively accounts for the phenomenon.

ISSN:0003-6951    

DOI:10.1063/1.100998

出版商:AIP    

年代:1989

数据来源: AIP