摘要:

Continuous wave operation of a quantum cascade laser at &lgr;=4.6 &mgr;m is reported above liquid nitrogen temperature. Optical powers of 15 mW at 50 K and 2 mW at 85 K are reported. The single mode spectrum is temperature tunable over 1.8 cm−1. These devices also operated in pulse mode with 20 mW peak power at 200 K. Gain measurements show evidence for ultralow linewidth enhancement factor &agr;<0.1. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114863

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We investigate the modulational instability in a nonlinear dispersive cavity which is driven to oscillation by degenerate parametric interaction in a nonlinear &khgr;(2)medium. Our analysis predicts the existence of stable temporal dissipative structures mediated by modulational instability when oscillation occurs through a subcritical instability. Decreasing the parametric gain below the subcritical bifurcation point, stability of these structures is broken and complicated temporal patterns in the form of weakly interacting solitary waves are predicted. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114864

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The crystallization properties of ZrF4‐based fluoride glasses containing PbF2are clarified and single‐mode fibers for an optical amplifier operating at 1.3 &mgr;m are fabricated. The crystallization tendency increases as the PbF2content of the glasses increases and the optimum PbF2content ranges from 11 to 12.5 mol % in terms of glass stability and refractive indices. The 4%‐&Dgr;nsingle‐mode fiber with a transmission loss of 44 dB/km at 1.2 &mgr;m was prepared as the amplifier host fiber. ZrF4‐based glass with a PbF2content of 11 mol % was used as a core glass and HfF4‐based glass was used as a cladding glass. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114865

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Great optical activity is realized by a vacancy ordered III2VI3compound (Ga0.3In0.7)2Se3with point group 6 which is based on wurtzite structure and characterized by the screw arrangement of cation atoms along thecaxis. The transition of the fundamental absorption edge is direct and the band gap is estimated to be 2.05 eV. An anomalous optical rotatory dispersion around the absorption edge is observed and the maximum rotatory power of 125°/mm is obtained at &lgr;=620 nm. The optical activity for red light is always above 60°/mm, that is 4–6 times as large as that of &agr; quartz. (Ga0.3In0.7)2Se3single crystal is very useful, especially for the He–Ne laser as an optically active substance; the rotatory power reaches 103°/mm, being more than 5 times of &agr; quartz. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114866

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We report on measurements of the potential profile of a GaAs/AlGaAsn‐i‐p‐imultiple quantum well structure using a scanning Kelvin probe force microscope (KFM). Using this novel technique we directly measure with meV precision and sub‐100 nm spatial resolution the potential difference betweenn‐i‐p‐ilayers with and without external optical excitation. The measured potential profiles, which have not been directly imaged previously, agree well with potential profiles calculated for optically excitedn‐i‐p‐istructures, but modified by band bending effects at the surface. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114867

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A method of fabricating submicron gratings for optoelectronic devices from a glass mask was proposed and demonstrated. The glass mask has gratings on both sides with a period of at least four times of the final feature size. By modifying the grating periods on the mask, one can achieve multiple‐period gratings with a very fine period spacing for advanced wavelength division multiplexing (WDM) devices. In this letter, we demonstrated 0.5 &mgr;m second‐order gratings for 1.55 &mgr;m distributed‐feedback lasers and gratings with a 6 A˚ period difference for WDM laser arrays using only optical sources. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114868

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Unlike conventional hybrid mode‐locking methods, a very low power (−1 dBm from a rf synthesizer) rf sinusoidal feeding signal is applied to the saturable absorber of the laser and ultrastable mode‐locked pulse train at 34 GHz repetition rate is achieved. A new physical mechanism for the efficient hybrid mode locking is proposed. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114869

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Conducting thin films on RuO2were deposited on glass by metalorganic chemical vapor deposition using tris‐trifluoroacetylacetonate‐ruthenium (III) [Ru(tfa)3] as precursor. Smooth, specular, and well adherent films were grown at temperatures as low as 400 °C, if the reaction gas contained water. RuO2was the only phase detected by x‐ray diffraction. The films were investigated by spectroscopic ellipsometry in the energy range of 1.5 to 5.0 eV. Thereby, the real (&Vegr;1) and imaginary (&Vegr;2) parts of the dielectric function were determined at room temperature. The optical constants could be described by three harmonic oscillators in combination with a Drude term for free‐charge carriers. ©1995 American Institute of Physics. 

ISSN:0003-6951    

DOI:10.1063/1.114870

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The thermal sensitivity of the efficient type II angular phase matching configuration for frequency doubling in 2‐amino‐5‐nitropyridinium‐dihydrogen crystals has been measured accurately. The measured thermo‐optic tuning sensitivity was found to be −0.303 mrad/ °C. A wavelength shift of the noncritical phase‐matching angle resulting from the thermal effect is shown to correspond to ad&lgr;/dTcoefficient of 0.176 nm/ °C. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114871

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We present an analysis of the high‐speed characteristics of quantum well lasers by simultaneously considering the effects of spectral hole burning, carrier heating, and carrier transport. An exact form of the small‐signal modulation response is obtained. The effects of carrier dephasing time in spectral hole burning, energy relaxation time in carrier heating, and diffusion‐capture‐escape times in carrier transport on the modulation response of quantum well lasers are theoretically investigated. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114872

出版商:AIP    

年代:1995

数据来源: AIP