摘要:

In a linear Nd3+fiber laser, spatial hole burning is eliminated by frequency shifters at the ends of the cavity. They introduce a frequency difference of 160 MHz between the two counterpropagating waves. The laser operates spontaneously and stable on a single longitudinal mode with ≊12 kHz bandwidth near 1088 nm. Tuning over 16.5 nm is achieved by two piezoelectrically driven etalons.

ISSN:0003-6951    

DOI:10.1063/1.106132

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We present a theoretical analysis of the optical applications of resonant tunneling diodes. The electronic properties are calculated with a self‐consistent traveling‐wave model that includes effective‐mass mismatches. The interband optical properties are calculated from a 4×4k⋅pband structure in the dipole approximation. We find that it is possible to operate a conventional device as an intersubband laser if the transition energy is large (∼0.5 eV) and the linewidth in minimal (∼5 meV). A bound‐state device can produce a modulation ratio of 5:1 at the excitonic peak with an absorption length of ∼ 40 &mgr;m in a waveguide geometry.

ISSN:0003-6951    

DOI:10.1063/1.106133

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

290 fs soliton pulses at 1.56 &mgr;m have been successfully obtained for the first time from a laser‐diode pumped erbium‐doped fiber laser with a nonlinear amplifying loop mirror. The laser was pumped by InGaAsP laser diodes and the threshold for starting the pulse oscillation was 50 mW. The passive mode‐locking continued to a pump power level as low as 10 mW. The repetition rate was uncontrollable and varied between the fundamental repetition rate of 5 MHz and 1.2–2 GHz.

ISSN:0003-6951    

DOI:10.1063/1.106134

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We have compressed strongly chirped optical pulses from a synchronously pumped In0.53Ga0.47As/InP multiple quantum well surface‐emitting laser operating with an external cavity. The pulses, initially exhibiting a strong up‐chirp with a time‐bandwidth product of more than 100 times the Fourier transform limit, were compressed to 77 fs using dispersion and soliton compression in a negative group‐velocity‐dispersion fiber. Chirp compensation using a diffraction grating pair followed by soliton compression in a fiber gave pulses as short as 21 fs.

ISSN:0003-6951    

DOI:10.1063/1.106135

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We report 10 mW cw room‐temperature operation of an electrically pumped vertical‐cavity surface‐emitting laser diode without a heat sink. This same laser produces 19 mW cw when cooled slightly below room temperature. In addition, we present a 9 mW cw laser with a threshold voltage of 1.6 V, and series resistance of 18 &OHgr;. These are the first surface‐emitting lasers fabricated by phase‐locked epitaxy. They are also believed to be the highest power and lowest threshold voltage electrically pumped vertical‐cavity structures reported to date. These results establish that phase‐locked epitaxy has important applications in the fabrication of surface‐emitting lasers and many other structures with similar materials requirements.

ISSN:0003-6951    

DOI:10.1063/1.106414

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We have experimentally observed the relatively low‐power self‐switching of polarization ellipticity along the profile of initially circularly polarized picosecond pulses in a spun birefringent fiber. The switching and pulse breakup effects originate from the intensity‐dependent modulation of the birefringence beat length.

ISSN:0003-6951    

DOI:10.1063/1.106139

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

High‐power cw operation of horizontal‐cavity, monolithic InGaAs/GaAs surface‐emitting lasers with all dry etched micro‐mirrors has been demonstrated for the first time. The 45° and 90° micro‐mirrors of the devices were fabricated by ion‐beam etching and reactive ion etching techniques, respectively. Threshold‐current densities of less than 500 A/cm2, external differential quantum efficiencies of 10% (0.12 W/A) from the emitting facet, and output powers in excess of 100 mW were achieved from uncoated devices driven under cw operation.

ISSN:0003-6951    

DOI:10.1063/1.106140

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Ion irradiation was used to pattern a region of red‐light emitting porous silicon by eliminating visible‐light photoluminescence (PL). The PL peak wavelength is approximately 735 nm and shows little dependence on the excitation‐light wavelength. The ratio of PL intensities for different excitation wavelengths was shown to be proportional to the ratio of the absorption coefficients. Below saturation, the integrated PL intensity increased linearly with excitation‐light power density.

ISSN:0003-6951    

DOI:10.1063/1.106141

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Particle‐in‐cell/Monte Carlo simulations of glow discharges between parallel plate electrodes indicate that operation at frequencies above 13.56 MHz offers a number of attractive features for plasma processing applications. Plasma density and ion current scale approximately as the square of frequency, but maximum ion energy is unaffected to first order when applied voltage, pressure and electrode spacing remain constant. In addition, raising frequency decreases sheath thickness, thereby increasing ion directionality in the sheath at constant pressure. By manipulating both frequency and rf voltage, it is possible to control ion current and energy independently.

ISSN:0003-6951    

DOI:10.1063/1.106112

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We report on measurements of vacuum field emission from ungated field emission cathode arrays fabricated from Si‐TaSi2eutectic composite wafers. The Si‐TaSi2material is an ideal candidate for large area field emission array cathodes due to the large density of TaSi2fibers incorporated into the Si matrix, the high melting point of the TaSi2material, the ease with which single‐crystal large diameter (2.5 cm) material can be fabricated, and the promise of integrability of the field emission array with conventional Si technology through the use of epitaxial Si layers grown on the cathode backplane.

ISSN:0003-6951    

DOI:10.1063/1.106113

出版商:AIP    

年代:1991

数据来源: AIP