摘要:

An experimental and theoretical study on temperature dependence of the threshold current densityJthand differential efficiency &eegr;dfor the InGaAsP/GaAs laser diodes emitting at &lgr;=0.8 &mgr;m was performed. Threshold current densityJthincreases and differential efficiency &eegr;ddecreases as temperature is increased mainly because of thermal broadening of the gain spectrum. However, the measured temperature dependence ofJthand &eegr;dcould not be explained when only this effect was considered. In this letter, the temperature dependence of momentum relaxation rate ℏ/&tgr; of carriers was investigated by performing the photoluminescence study. At high temperature, increase of the momentum relaxation rate ℏ/&tgr; leads to reduction of the gain and mobility and increase of the optical loss, causing higherJthand lower &eegr;das experimentally observed. The resulting theoretical model provides a good explanation for the mechanism of the increase ofJthand decrease of &eegr;d. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114193

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A bifunctional chromophore has been developed which serves as a charge transporting agent as well as a second‐order nonlinear optical compound. The chromophore has been incorporated into an inert polymer to form a photorefractive material when doped with a photocharge generation sensitizer. The dependence of the four‐wave mixing diffraction efficiency, holographic grating writing rate, and two‐beam coupling gain on the chromophore concentration has been studied. The results confirm the photorefractive character of the composite. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114194

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Light emission from vertical cavity surface emitting lasers (VCSELs) is modeled as directed radiation away from a localized source within the VCSEL optical cavity into an open system as a continuous function of frequency, analogous to antenna radiation, but with field sources provided by spontaneous emission and gain. To allow near‐analytical solution, a quasi‐one‐dimensional system is analyzed. This approach reproduces the familiar threshold condition, mode gain times lifetime equals unity, at the cavity quasimode frequency; however, it also predicts that lasing is not restricted to the quasimode frequency. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114195

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We report a wavelength division demultiplexer (WDDM) using collinear surface‐normal input and output coupling. The reported device employs polymer‐based multiplexed waveguide holograms in conjunction with substrate guided waves. A two‐channel WDDM device operating at 700 and 738 nm with diffraction angles of 45° and 50° are demonstrated. The peak diffraction efficiencies of 80% and 77% are measured for these two channels. A crosstalk of −31 dB between the two channels is measured. Variations of the diffraction efficiencies and of the bandwidths as a function of film thickness and index modulation are further considered. A good agreement between theoretical analysis and experimental results is obtained. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114196

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We demonstrate difference frequency generation (DFG) of 8.66–11.34 &mgr;m wavelength light in intersubband InGaAs/AlAs quantum wells by mixing of 1.92 &mgr;m±25 nm and 2.39 &mgr;m±39 nm. The peak DFG second order nonlinear susceptibility &khgr;(2)is measured to be 12±1 nm/V, more than 65 times that of GaAs, at a difference frequency output wavelength of 9.50 &mgr;m. The intersubband absorption for the 1–2 and 1–3 transitions is measured to be 9.3 and 2.1 &mgr;m, respectively. Second harmonic generation (SHG) of 4.76, 5.12, and 5.36 &mgr;m light with a CO2laser is observed with a peak SHG &khgr;(2)of 52±3 nm/V. Good agreement of experiment with theory is found for both the linear and nonlinear optical properties. This demonstration of mid‐infrared DFG opens the possibility for monolithic diode laser pumps and compact waveguide frequency converters as tunable midinfrared sources. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113512

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Blue‐violet gallium nitride (GaN) light emittingp‐njunctions were grown by the method of electron cyclotron resonance‐assisted molecular beam epitaxy. This method has been modified to minimize plasma induced defects. Contrary to similar devices grown by metalorganic chemical vapor deposition, these devices do not require any postgrowth annealing to activate the Mg acceptors in theplayer. These devices turn‐on at approximately 3 V and have a spectral emission peaking at 430 nm. ©1995 American Institute of Physics. 

ISSN:0003-6951    

DOI:10.1063/1.113513

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We calculate the three‐wave mixing susceptibility of an asymmetric AlGaAs quantum well for difference‐frequency generation of mid‐infrared radiation. The effects of carrier injection and input field strength on the interband mixing process are considered. A peak susceptibility more than two orders of magnitude larger than that of bulk GaAs is obtained. Based on these results, the possibility of difference‐frequency mixing within a semiconductor quantum well laser is discussed.

ISSN:0003-6951    

DOI:10.1063/1.113514

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Low‐loss optical waveguides have been produced inz‐cut Sr0.6Ba0.4Nb2O6(SBN:60) and electro‐optic modulation has been demonstrated at a wavelength of 1.3 &mgr;m. The refractive index increase responsible for waveguiding results from a strain produced by a SiO2film which has been deposited on the surface of the substrate at 320 °C. The waveguides are formed in the crystal by dry etching of channels in the strain film. The resulting optical waveguides support both polarizations. Propagation loss values of 0.7 dB/cm for TM polarization and 1.6 dB/cm for TE polarization were measured. Electro‐optic modulation up to 22 MHz was performed on repoled samples using coplanar electrodes. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113515

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Measurements of the &agr;‐factor, the linewidth‐power product, and the differential gain in AlGaAs/GaAs vertical cavity surface emitting lasers are presented. The linewidth power product of 95 MHz mW which results in the &agr;‐factor of 3.7 is obtained. The &agr;‐factor as a ratio of the refractive index and gain derivatives with respect to the carrier density is also estimated. From the small signal modulation measurements of the resonance frequency, a differential gain of 3.7×1016cm2is obtained. The estimate of differential effective index is made difficult by an anomalously strong dependence of the emission wavelength on injection current. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113516

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Highly indium‐doped lithium niobate crystals have been grown. It was found that a LiNbO3:In (5 mol %) crystal had a similar high resistance to photorefraction as a LiNbO3:Zn (7.5 mol %) crystal. The result of x‐ray fluorescence showed that the doped concentration of In in LiNbO3:In (5 mol % in the melt) exceeds the concentration threshold of trivalant elements (3.0 mol % in the crystal). The LiNbO3:In (5 mol %) crystal is another doped LiNbO3crystal with high resistance to light‐induced refractive index damage. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113517

出版商:AIP    

年代:1995

数据来源: AIP