摘要:

We demonstrate optical polarization bistability in a semiconductor laser for the first time. Only the optical signal pulses are used as triggers for switching the transverse mode of the laser. The two stable states are identified as the transverse electric mode and the transverse magnetic mode, respectively, while the optical input consists of the transverse magnetic wave. Switching speeds up to a few hundred picoseconds have been achieved for both switch‐up and switch‐down.

ISSN:0003-6951    

DOI:10.1063/1.98314

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Optical demultiplexing characteristics are studied using a multielectrode distributed feedback laser amplifier. The gain maximum frequency is tunable over 20.6 GHz with a constant insertion gain (9.7±1.2 dB) and a constant gain bandwidth (2.9 GHz), without any mode jump, by changing the driving current of the divided two electrodes. A single optical signal can be selected from two optical inputs separated by 15.4 GHz with an extinction ratio of better than −20 dB.

ISSN:0003-6951    

DOI:10.1063/1.98315

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

An upconversion pumping scheme was used to produce cw laser action at 0.55 &mgr;m in YAlO3:Er3+at temperatures up to 77 K on the4S3/2→4I15/2transition. Two infrared dye lasers at 792.1 and 839.8 nm were used as the pump sources for stepwise two‐photon excitation of the4S3/2upper laser level at 18 406 cm−1. The laser operates in the fundamental TEM00mode, and a cw output power of ∼1 mW was achieved with ∼200 mW pump power from each infrared dye laser.

ISSN:0003-6951    

DOI:10.1063/1.98316

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

A two‐step metalorganic vapor phase epitaxial growth technique for fully planar GaAs/GaAlAs single quantum well buried heterostructure lasers with oxygen‐doped semi‐insulating blocking layers is described. GaAlAs blocking layer with resistivity above 106&OHgr; cm is reproducibly obtained by introducing oxygen at a concentration above 0.03 ppm during the growth. The selective growth mode of GaAlAs layers in etched grooves is studied to realize fully planar buried structures. Lasing characteristics with threshold current of 19 mA, external differential quantum efficiency of 50%, and maximum light output power of 100 mW/facet are confirmed.

ISSN:0003-6951    

DOI:10.1063/1.98317

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

In this letter we report the successful combination of a low‐loss buried waveguide providing two‐dimensional optical confinement with an active gain medium. We have thereby realized a planar and monolithic composite cavity laser where the laser cavity consists of distinct regions of optical gain combined with distinct regions of low‐loss optical waveguide. The low threshold currents of these strucures (<10 mA) confirm the low loss and waveguiding nature of the waveguide regions. The ability to make these types of structures has applications for window lasers, monolithic waveguides, and monolithic integration of electrical and optical components.

ISSN:0003-6951    

DOI:10.1063/1.98318

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Time‐dependent density measurements of the lowest xenon excited states (5p56s) in electron beam (e‐beam) pumped XeCl laser mixtures (nonlasing) are performed using pulsed hook interferometry. Thee‐beam pulse length is ≊0.45 &mgr;s (full width at half‐maximum) with an average excitation rate of ≊250 kW/cm3. Density differences (&Dgr;N*) of transitions at 823.2 nm (6s[3/2]02–6p[3/2]2), 828.0 nm (6s[3/2]01–6p[1/2]0), and 840.9 nm (6s[3/2]02–6p[3/2]1) are obtained for various HCl and Xe concentrations. For a 98.3% Ne/1.5% Xe/0.16% HCl mixture at 3000 Torr, &Dgr;N* (823.2 nm) and &Dgr;N*(828.0 nm) are relatively constant at ≊3×1014and ≊1.7×1014cm−3, respectively. At lower initial HCl concentrations, the &Dgr;N*(823.2 nm) density starts out similar to the 0.16% HCl case, but tends to increase dramatically during thee‐beam pulse. For a 0.04% HCl mixture, a &Dgr;N*(840.9 nm) density of ≊4.5×1015cm−3is measured at the end of thee‐beam pulse. Preliminary comparisons of the data with a computer model show good agreement for HCl concentrations ≥0.16%, but disagreements at leaner concentrations.

ISSN:0003-6951    

DOI:10.1063/1.98319

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The reported experimental results demonstrate the influence of the substrate‐induced strain on the In incorporation coefficient in the growth of AlInAs by molecular beam epitaxy. AlInAs has either been grown lattice matched to InP or with a 2.3% lattice mismatch with GaAs. The In incorporation coefficient has been determined through reflection high‐energy electron diffraction intensity oscillations. The strain effect on the In incorporation coefficient is supported by a thermodynamic analysis applied to the more simple but similar case of strained InAs growth.

ISSN:0003-6951    

DOI:10.1063/1.98320

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We observed the growth of epitaxial Al(111) films on Si(111) at room temperature by the partially ionized beam deposition technique. The films were deposited in a conventional vacuum condition withoutinsitucleaning. The beam contained 0.3% of Al self‐ions and a bias potential of 1 kV was applied to the substrate during deposition. X‐ray diffraction (pole figure) revealed that one of the two possible twin structures, with the Al⟨1¯10⟩∥Si⟨1¯10⟩ orientation, was preferentially grown on the Si substrate.

ISSN:0003-6951    

DOI:10.1063/1.98321

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Electrical characteristics of GaAs( p)/Si(n) interface were determined from capacitance‐voltage (C‐V), current‐voltage (I‐V), and secondary ion mass spectroscopy (SIMS) measurements and compared to those on GaAs( p) epitaxial layes on GaAs(n) substrates. The comparison was made between the junctions as grown and after an anneal at 850 °C for 20 min in 10% forming gas under an As overpressure. For the GaAs/Si junction the ideality factor changed from 2 or larger to 1.5 and the apparent intercept voltage changed from 2.5 to 1.3 V after annealing. For the GaAs homojunction, the intercept voltage increased from 1.1 to 1.3 V. In addition, the excess current in the forward and reverse bias conditions dropped drastically in the heterojunction. No movement of the metallurgical junction was discernible to within the resolution capability of SIMS. The junction properties obtained by annealing suggest an atomic restructuring of the Si(100) interface during growth or annealing. These new results raise the possibility that the GaAs/Si interface can be made into an electrically viable junction and incorporated into active devices.

ISSN:0003-6951    

DOI:10.1063/1.98322

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We report on the fabrication and the characteristics of Al0.4Ga0.6As/GaAs tandem solar cells. The annealing characteristics of GaAs tunnel diodes are studied. It is found that the degradation of the tunnel peak current density by the annealing is suppressed for the diodes composed of a GaAs tunnel junction sandwiched between AlGaAs layers. The tunnel junction is applied to the interconnect between the Al0.4Ga0.6As top cell and the GaAs bottom cell for the tandem solar cell. The cell has a short‐circuit current density of 13.8 mA/cm2, an open‐circuit voltage of 2.10 V, a fill factor of 70.0%, and a conversion efficiency of 20.2% at 1 sun, AM1.5. This efficiency is the highest ever reported at 1 sun for tandem solar cells.

ISSN:0003-6951    

DOI:10.1063/1.98272

出版商:AIP    

年代:1987

数据来源: AIP