摘要:

A careful analysis of the gain using the amplified spontaneous emission in semiconductor lasers concludes that there is a spatial distribution of the gain. A twofold distribution is observed in the planes parallel and perpendicular to the junction with different decreasing variations from the laser axis to the edge of the radiation lobe. Collecting the entire emitted light beam gives usually too low gain values. Gain measurements restricted to the region around the laser beam axis lead to an improvement of the gain value determination being within 96% of the actual value determined by the laser threshold.

ISSN:0003-6951    

DOI:10.1063/1.101321

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The application of a frequency chirped pulse amplification sheme for XeCl excimer lasers is theoretically evaluated by solving the Maxwell–Bloch equations [A. Icsevgi and W. E. Lamb, Jr., Phys. Rev.185, 517 (1969)]. The calculated effective saturation energies for subpicosecond nonchirped laser pulses are much higher than the values that have been obtained experimentally. If this evidence indicates that optical nonlinear effects at high laser intensities are reducing the extraction energy, frequency chirped amplification followed by pulse compression, as demonstrated with solid‐state lasers, is also useful with XeCl lasers. This helps to reduce the peak laser intensity and increase the extraction energy.

ISSN:0003-6951    

DOI:10.1063/1.101322

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

A GaAs/AlGaAs Mach–Zehnder modulator using a push‐pull drive configuration is reported. The bandwidth/drive‐voltage figure of merit is approximately double that of an equivalent single‐sided device and is the highest reported for any non‐traveling‐wave structure.V&pgr;is 9 V at 1150 nm. Using unterminated drive a bandwidth of 6.25 GHz is achieved.

ISSN:0003-6951    

DOI:10.1063/1.101323

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

A novel integrated optical frequency shifter that utilizes guided‐wave acousto‐optic Bragg diffractions in cascade from two tilted and counterpropagating surface acoustic waves is reported. The doubly and frequency‐shifted diffracted light propagates in a fixed direction, but spatially resolved from the incident light, irrespective of the magnitude of frequency tuning. A preliminary device fabricated in aY‐cut LiNbO3planar waveguide has demonstrated a gigahertz frequency shift, a tunable bandwidth of 165 MHz, and other desirable characteristics at the optical wavelength of 0.63 &mgr;m. These preliminary results suggest that a compact integrated acousto‐optic frequency shifter module may be realized in a common LiNbO3substrate 0.2×10×1.5 cm3in size.

ISSN:0003-6951    

DOI:10.1063/1.101392

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Third‐harmonic generation has been measured in poly(2,5‐dimethoxyp‐phenylene vinylene) thin film. The third‐order optical susceptibility, &khgr;(3), was evaluated to be 5.4×10−11esu at 1.85 &mgr;m wavelength. This &khgr;(3)value is about one order higher than that for poly(p‐phenylene vinylene) and almost the same value as for poly(n‐BCMU diacetylene) which possesses the highest &khgr;(3)value among processible (solvent castable) polymeric materials.

ISSN:0003-6951    

DOI:10.1063/1.101393

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Sidebands are observed at 72 GHz off an optical carrier at 633 nm. The laser beam is phase modulated in a LiNbO3crystal which is exposed to a mm‐wave field inside a Fabry–Perot resonator. Under optimum phase‐matching conditions we obtain a modulation index of 5% derived from 200 mW microwave power. Phase matching is obtained by guiding the light beam on a zig‐zag path under internal total reflections. For this unconventional type of phase matching, the optical wave fronts travel at twice the speed of the modulating wave along the resonator axis.

ISSN:0003-6951    

DOI:10.1063/1.101324

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Using intracavity frequency doubling of a diode laser pumped 946 nm Nd:YAG laser, 3.1 mW of blue output power at 473 nm was obtained. Angle‐tuned, type‐I frequency doubling in potassium niobate was employed, and both the KNbO3and Nd:YAG crystals were used at room temperature.

ISSN:0003-6951    

DOI:10.1063/1.101394

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Quadratic phase modulation is used to measure the electronic third‐order nonlinear optical susceptibility of thin polymer film solid solutions of organic dyes. This simple technique is shown to provide quick measurements of the &khgr;(3)1133component of the third‐order optical susceptibility. The measured quadratic electro‐optic coefficient of 7.5 wt. % (2.5 mol %) of a dicyanovinyl azo dye in poly(methyl methacrylate) (PMMA) is 4.4×10−21m2/V2, which corresponds to a direct current Kerr coefficient of 1.4×10−11esu. The electronic and orientational mechanisms, whose response times are faster than 30 ps, are discussed.

ISSN:0003-6951    

DOI:10.1063/1.101376

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The deposition of SnO2films has been demonstrated using an ArF (193 nm) excimer laser to drive the photochemical reactions of mixed SnCl4and N2O vapors. Without any annealing, films 100 nm thick grown on room‐temperature substrates have resistivities as low as 0.04 &OHgr; cm. The optical band gap of 3.20 eV and transmission cutoff wavelength of 330 nm compare favorably with the best films obtained using alternate higher temperature techniques. Subsequent annealing does not increase the film’s conductivity. Selective area growth of 10‐&mgr;m‐wide lines has been performed using proximity printing. The maximum temperature excursion during the laser pulse is estimated to be 300–400 °C.

ISSN:0003-6951    

DOI:10.1063/1.101395

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Data are presented on a nonplanar graded barrier quantum well heterostructure window laser formed by a single metalorganic chemical vapor deposition (MOCVD) growth. By utilizing a selectively etched substrate, a transparent window region is formed in the vicinity of the facets thereby relaxing the maximum power limit imposed by catastrophic optical degradation. The ultimate output power available from such devices is approximately 50% higher than from devices with the same structure but grown on unetched substrates. The processing required for device fabrication is minimized by taking advantage of the properties of MOCVD growth on nonplanar substrates.

ISSN:0003-6951    

DOI:10.1063/1.101307

出版商:AIP    

年代:1989

数据来源: AIP