摘要:

A simple model for the linewidth enhancement factor &agr; and its frequency dependence in semiconductor lasers is presented. Calculations based on this model are in reasonable agreement with experimental results.

ISSN:0003-6951    

DOI:10.1063/1.94054

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Measured effective mode indices on a day to day basis reveal an oscillatory behavior which indicates that the index profile of proton‐exchanged LiNbO3waveguides evolves as a function of time. It is suggested that the profile instability might be brought about by a continuous migration of protons within the thickness of the guiding layer. Some index profile modificaiton may also be introduced during fabrication due to structural changes in the crystal as a function of exchange time.

ISSN:0003-6951    

DOI:10.1063/1.94055

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Hydrogenated amorphous (a‐C:H) films were prepared by rf‐plasma deposition from benzene vapor. Complete optical absorption spectra from the UV to the IR (0.2–20.0 &mgr;m) have been measured. The optical gap depends linearly on hydrogen content andEoptcan be varied between 0.8 and 1.8 eV. For energies belowEoptthe films are almost transparent and absorption is especially low in the 2–6‐&mgr;m region (e.g., &agr;=15 cm−1at &lgr;=2.8 &mgr;m). Sharp C–H stretch absorption bands occur near 3.4 &mgr;m, giving insight into the microstructure of the films. A newly reported weak band at 3.03 &mgr;m is first evidence for C–C triple bonds (sp1hybridization) ina‐C:H, wheresp3(single) andsp2(double) C–C bonds dominate.

ISSN:0003-6951    

DOI:10.1063/1.94056

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Using pulsed optical excitation (h&ngr;>Eg), we have observed laser oscillations at 3.53 &mgr;m from the internald‐shell transitions of Fe2+inn‐type InP:Fe. The semiconducting nature of the InP host plays an important role in the pumping of the Fe2+excited state, which occurs via the capture of a conduction‐band electron by Fe3+created during the exciting pulse.

ISSN:0003-6951    

DOI:10.1063/1.94057

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Runaway self‐absorption within a CO2laser cavity, recently reported at high pressure, has also been observed in a low pressure (50 mbar), multikilowatt cw CO2laser. A numerical model of the laser discharge is used to simulate the runaway absorption and gives results consistent with experiment. Runaway absorption is readily suppressed by eliminating regions of stagnant gas within the cavity.

ISSN:0003-6951    

DOI:10.1063/1.94058

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Equations are developed which describe the coupling between radiation and confined (guided wave or surface plasmon) modes in the presence of an intensity‐dependent index of refraction. Solutions are presented for three numerical examples and comparisons are made with asymptotic solutions. We find that under certain conditions, the addition of the nonlinear index drastically alters the coupling and gives rise to the possibility of optical switching. Experimental parameters for optimizing such switching are discussed.

ISSN:0003-6951    

DOI:10.1063/1.94059

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

A phase‐locked multiple quantum well (GaAl)As injection laser is demonstrated to emit over 1.5 W/mirror (>3 W total) cw output power at ∼8350 A˚ with a maximum power conversion efficiency of 17.4%.

ISSN:0003-6951    

DOI:10.1063/1.94060

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

First results are presented demonstrating the feasibility of using an integrated optics array of Mach–Zehnder dielectric‐waveguide interferometers to measure the phase and amplitude across an optical wave front. The interferometers are formed from single‐mode waveguides produced by Ti diffusion into LiNbO3. The spacing between the arms of the interferometer is 20 &mgr;m. The phase difference &fgr; between the optical waves incident on the two interferometers arms is measured and compared with theory. The excellent and reproducible agreement between experiment and theory over a number of interferometers suggests that the accuracy of the wave front measurement sensor should be attractively high, limited only by signal statistics and noise considerations. As example, a sensor design is given for which the rms deviation (1&sgr;) in the value of &fgr; is less than 4.5° (the rms deviation in the optical path difference is less than &lgr;/80).

ISSN:0003-6951    

DOI:10.1063/1.94052

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

We report a new mechanism of direct frequency modulation, the cavity‐mode enhanced frequency modulation (CME‐FM), using the newly developed cleaved‐coupled‐cavity (C3) semiconductor laser. In this operation, one of the diode of the C3laser was operated as a laser, while the other diode was operated as a frequency modulator. It was shown that a very large frequency excursion of 150 A˚ and frequency tuning rate of 10 A˚/mA have been obtained with a C3GaInAsP crescent laser operating at 1.3 &mgr;m. Time‐resolved spectral and spectral‐resolved pulse response measurements also showed that such C3lasers operated in highly stable single‐longitudinal mode at all times even under high‐speed direct frequency modulation. In addition to the important application as the optical source in FM optical communication systems, the present CME‐FM C3laser can also be used as the optical source in wavelength‐division multiplexing systems. Further, it opens the possibility of ultrahigh capacity multilevel optical FM information transmission systems.

ISSN:0003-6951    

DOI:10.1063/1.94053

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

An easily fabricated high‐power index‐guided laser, the twin‐channel substrate‐mesa‐guide (TCSM) laser, has been developed for applications in recording, printing, and communications. The TCSM laser is fabricated by one‐step organometallic vapor phase epitaxy (OMVPE) on photolithographically patterned and etched substrates. Linear output characteristics were observed to 40 mW cw with corresponding operation in zero order lateral and transverse modes and no astigmatism. Stable single longitudinal mode oscillation also resulted from the strong refractive index guiding produced by the nonplanar structure.

ISSN:0003-6951    

DOI:10.1063/1.94061

出版商:AIP    

年代:1983

数据来源: AIP