摘要:

The effect of optical feedback on the intensity‐noise spectrum and the longitudinal‐mode line shape of a 1.55‐&mgr;m InGaAsP laser is investigated for reflections arising from the far end of a 7.5‐km‐long fiber. The intensity noise near the relaxation‐oscillation frequency is significantly enhanced by the reflection feedback. Owing to the intercavity coupling, the enhancement is, however, frequency dependent and the noise spectrum exhibits high‐contrast modulations with a period corresponding to the fiber‐cavity longitudinal‐mode separation. A simple rate equation model is used to explain the observed behavior.

ISSN:0003-6951    

DOI:10.1063/1.95322

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Uniform semiconductor laser arrays tend to oscillate in a superposition of their supermodes, thus leading to large beam divergence and spectral spread. Discrimination among the supermodes in phase‐locked arrays is discussed theoretically. It is shown that supermode discrimination in gain‐guided arrays, in favor of the fundamental supermode, is made possible by the near‐field interference patterns which result from the complex optical fields of the gain‐guided lasers. A fundamental supermode operation is demonstrated, for the first time, in GaAlAs/GaAs gain‐guided laser arrays. This is achieved by control of the current (gain) profile across the array by means of individual laser contacts.

ISSN:0003-6951    

DOI:10.1063/1.95323

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Electro‐optic data for uniaxially drawn polyvinylidene fluoride are presented. Measurements at successively increasing fields show a hysteresis effect. The observed electro‐optic hysteresis is compared with theoretical predictions of hysteresis in ferroelectric ceramics.

ISSN:0003-6951    

DOI:10.1063/1.95324

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Direct polarization switching controlled by the level of the injection current is achieved in InGaAsP lasers operating near the polarization transition temperature. The laser output can be switched from a pure TM00mode at low injection currents to a TE00mode at high currents with high extinction ratios and nanosecond response time. Conditions for polarization switching in InGaAsP and AlGaAs lasers at room temperature are also discussed.

ISSN:0003-6951    

DOI:10.1063/1.95325

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

(GaAl)As/GaAs multiple quantum well channeled‐substrate lasers with lateral index guiding have been made by molecular beam epitaxy. They operate stably in a single longitudinal mode.

ISSN:0003-6951    

DOI:10.1063/1.95326

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Mutual phase locking has been achieved through series connection of a semiconductor laser and a Gunn diode oscillator. Experimental results obtained demonstrate a mutual interaction between the two oscillators which results in a short term Gunn diode oscillator stability and improved spectral purity of its output. We also observe a narrowing of laser pulses and an improvement in regularity.

ISSN:0003-6951    

DOI:10.1063/1.95327

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Spatially resolved electric field measurements in the cathode fall region of a glow discharge are performed using optogalvanic detection of He Rydberg atoms. The large linear Stark effect of Rydberg levels provides an accurate, sensitive measure of discharge electric fields.

ISSN:0003-6951    

DOI:10.1063/1.95328

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Defect centers in optical fibers induced by drawing were investigated using the electron spin resonance technique. The hydrogen hyperfine (hf) doublet with splitting of 119 G was observed for both GeO2‐doped and pure silica optical fibers, which contain few hydroxyl ions. The hf peak intensity was directly proportional to specific surface area of optical fibers. These results indicate that the hf doublet arises from the hydrogen interaction with a drawing‐induced germanium defect center at or near the optical fiber surface.

ISSN:0003-6951    

DOI:10.1063/1.95329

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Bulk specimens (0.4–4 g mass) of the alloy Pd40Ni40P20have been undercooled consistently to the glass state, with no detectable superficial crystallinity, in a molten flux of dehydrated boron oxide. The minimum dimension of the most massive glass specimen, so formed, was 1.0 cm. The absence of crystallinity in the specimens was confirmed by x‐ray diffraction, scanning electron microscopy, and calorimetry.

ISSN:0003-6951    

DOI:10.1063/1.95330

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

UV‐laser photodeposition has been used to predispose surfaces to pyrolytic chemical vapor deposition (CVD) of Al from triisobutylaluminum. Two laser beam (UV and IR) experiments indicate that the predisposition is due to the formation of a catalytic surface for heterogeneous chemistry. Time‐resolved transmission measurements indicate that a few photodeposited monolayers are sufficient to nucleate CVD growth. The technique may be generally useful for maskless patterned growth by CVD processes with large nucleation barriers.

ISSN:0003-6951    

DOI:10.1063/1.95331

出版商:AIP    

年代:1984

数据来源: AIP