摘要:

An all-optical inverter, which operates over a range of 15–1400 K, was demonstrated in an erbium-doped lutetium aluminum garnet crystal with 787.3, 787.9 and 790 nm laser diodes. In the case of 787.3 nm, the reversed-phase wave forms were obtained in a temperature range of 15–1100 K. In the case of 787.9 and 790 nm, they were observed up to 1400 K. It has been confirmed that the negative nonlinear absorption effect can be explained by considering an enhanced absorption model for a five-level system of theEr3+ion. The effect has a characteristic, which is almost independent of the ambient temperature because it is formed by optical transitions of the inner shell of the erbium atom. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120768

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

We report optical mixing with difference frequencies to 211 GHz in 50 nm gate pseudomorphic InP-based high electron mobility transistors (HEMTs). To our knowledge, this is the highest frequency optical mixing signal obtained in three terminal devices. To detect the signals at these frequencies, a novel three-wave-mixing configuration was employed. To demonstrate the wide tunability of this setup, a sweep of frequencies from 160 to 190 GHz was performed. The optically generated millimeter wave signals were downconverted to 97 GHz and radiated. For the radiation experiments, tunable baseband signals were also added by injection into the gate terminal of our HEMTs, thereby providing a method to transmit information. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120769

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

We demonstrate experimentally an all-fiber nonlinear optical modulator which can find application for high power (greater than 20 W) single-mode fiber lasers. Stimulated Raman scattering is used to transfer the amplitude modulation from a low-power signal beam at the Stokes frequency onto a high-power beam. Efficient modulation of 1064 nm pump radiation by 100 ps Stokes pulses is demonstrated in a highly Ge-doped fiber. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120770

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

We present a study on a novel method for the determination of the cavity losses in semiconductor lasers. The method we use involves Fourier analysis of the Fabry–Pe´rot mode spectrum when operating the device below lasing threshold. The observation of the decay rate of higher order harmonics in the Fourier analysis of the spectra allows us to determine the amount of cavity propagation loss/gain. A comparison between experimental and calculated data for an AlGaInP laser at 670 nm showed good agreement up to an injection current of0.93×Ith.This method therefore provides a generalization of the Fabry–Pe´rot contrast measurement method for extracting cavity losses from spectral information. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120771

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Polymer optical fibers have received much attention in recent years as they can replace silica glass fibers in local area nets in the future. A neodymium ion(Nd3+)-doped poly(methyl methacrylate) (PMMA) fiber has been made fromNd3+containing PMMA as a core and silica resin as claddings. Fluorescence of the fiber results from the transition of4G5/2to4I9/2in a three energy level system. Amplified spontaneous emission (ASE) at 575 nm has also been observed and the critical power at a pump wavelength of 514.5 nm for the onset of ASE has been found to be 85 mW. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120772

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Optically pumped laser emission has been observed from thin films of 8-hydroxyquinolinato aluminum (Alq) doped with a DCM dye deposited on a diffraction grating formed by imprinting a film of BCB with a mold. The BCB film, which is 4 &mgr;m thick, is deposited on a silicon or a flexible plastic substrate. Laser emission occurs at a wavelength near 655 nm which corresponds to the third order of the grating, which has a periodicity of∼0.6 &mgr;m.©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120773

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

An all fiberoptic configuration to generate multi-wavelength picosecond optical pulses by self-seeding of a gain-switched 1.53 &mgr;m semiconductor laser has been proposed and experimentally demonstrated. The configuration consists of a 600 m highly dispersive fiber and an optical loop mirror multiplexer. Four-wavelength optical pulses with a spectral separation of 2.6 nm, a side-mode-suppression ratio of 16 to 20 dB, and a pulse width of 75 ps have been generated. The repetition rate of these pulses has been multiplied to 3.4 GHz, and totally 13.6 Gb/s(4×3.4 Gb/s)pulse signals have been produced. With the optical bit patterns generated from the multiplexer, output pulses with one, two, or four wavelengths at different combinations can be obtained. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120774

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

We report the fabrication and characterization of GaN-based double heterostructure light emitting diodes grown by molecular beam epitaxy on Si(111) substrates. Light emitting diode operation is achieved by using the conducting Si(111) substrate as a backsidencontact and a standard transparent Ni/Aupcontact. We observe electroluminescence peaked in the ultraviolet∼360 nm,with a full width at half maximum of∼17 nmand in the violet at ∼420 nm. Electron microscopy studies indicate a high density of threading and planar defects. Consequences of these are discussed. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120775

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Image storage has been investigated with the biphotonic holographic method in an azo/polymer film. Experimental results show that this biphotonic holographic storage has high spatial resolution and exhibits an image enhancement effect after blocking the noncoherent light. The mechanism of biphotonic holographic storage is attributed to the redistribution ofcisform azo molecules induced by both coherent light and noncoherent light. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120776

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

The electric field in the vicinity of a metallic edge attached to a dielectric half-space is calculated analytically. The resulting electric field is used to evaluate the current emitted from the edge using the Fowler-Nordheim formula. It is shown analytically that the emitted current is proportional to the dielectric coefficient of the material. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120802

出版商:AIP    

年代:1998

数据来源: AIP