摘要:

A maximum cw power of 90 mW at 25 °C was obtained for a GaInAsP/InP laser with a semi‐insulating InP current blocking layer grown by metalorganic vapor phase epitaxy on ap‐type InP substrate, a 700‐&mgr;m‐long cavity, and an antireflection coating on the front facet. The 3 dB bandwidth was in excess of 6 GHz with a low parasitic capacitance of 15 pF despite the long cavity. The semi‐insulating layer with the resistivity of 5×107&OHgr; cm was formed by doping only Fe. The current blocking characteristics of the blocking layer with the same configuration as the lasers were examined under various temperatures.

ISSN:0003-6951    

DOI:10.1063/1.100762

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

An optical wavelength demultiplexer using an asymmetricYjunction is numerically analyzed and the experimental results are reported. This demultiplexer utilizes both the mode splitting characteristic of an asymmetricYjunction and the waveguide dispersion of channel waveguides. Analysis shows that the device with step‐index profile has more than 20 dB isolation for wavelengths with 6.5% separation from the center wavelength. The fabricated device composed of two‐step ion exchanged soda‐lime glass waveguides coated asymmetrically with Corning 7059 glass thin film separated the lights of 0.63 and 0.84 &mgr;m wavelengths.

ISSN:0003-6951    

DOI:10.1063/1.100763

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Optical absorption edges of mixed AgClxBr1−x(0≤x≤1) crystals and polycrystalline fibers were investigated as a function of composition. Both visible edge, resulting from electronic transitions, and infrared edge due to multiphonon processes behave as the one‐mode (amalgamation) type of mixed crystals, shifting continuously with composition. Quantitative expressions were used to discuss the results. Polycrystalline extruded fibers preserve this spectral window of silver‐halide crystals, except for slight deviations which are explained by the small‐grain structure of the fibers.

ISSN:0003-6951    

DOI:10.1063/1.100764

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Optical fiber exposed to high‐pressure hydrogen gas for 3–4 days, and subsequently heated in air at temperatures in the range 250–500 °C for 8–24 h, shows an enhanced second‐harmonic conversion efficiency after seeding with 1.06 &mgr;m and 532 nm light, when compared with untreated fiber seeded under similar conditions. Up to now, an enhancement by as much as a factor of 4.4 has been observed. Some possible correlations between this enhancement and the change in the defect content of the fiber due to the H2‐heat treatment are pointed out.

ISSN:0003-6951    

DOI:10.1063/1.100765

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The cavity length dependence of the threshold current for separate confinement quantum well lasers with a single well, three wells, and six wells is studied. Only the single quantum well laser showed the anomalous increase of threshold current at short cavity length. Comparison of the experimental results with theoretical calculations concludes that the polarization enhancement of the oscillator strength in a quantum well has to be taken into account in the gain spectrum calculation of the quantum well laser.

ISSN:0003-6951    

DOI:10.1063/1.100766

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Quantum well lasers are shown to exhibit flattened broadband gain spectra at a particular pumping condition. The gain requirement for a grating‐tuned external cavity configuration is examined and applied to a semiconductor quantum well laser with an optimized length of gain region. The predicted very broadband tunability of quantum well lasers is confirmed experimentally by grating‐tuning of uncoated lasers over 85 nm, with single longitudinal mode output power exceeding 200 mW.

ISSN:0003-6951    

DOI:10.1063/1.100767

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The first observation of nonlinear reflection from a Bragg reflector composed of Ga0.8Al0.2As/AlAs layers due to the band filling effect was measured by the pump probe method. The nonlinearity was primarily due to saturable absorption. Optically induced reflectivity changes of as much as 38% were measured.

ISSN:0003-6951    

DOI:10.1063/1.100768

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

We report, for the first time, the fabrication of negative index‐change planar waveguide microlenses in GaAs by using ion milling. The waveguide lenses that have been fabricated and tested include single lenses and lens arrays of analog Fresnel, chirp grating, and hybrid analog Fresnel/chirp grating types. We have obtained small focal spot sizes and good efficiencies in such preliminary components. Ion milling has been shown to be a simple and versatile technique for fabrication of waveguide lenses in GaAs and applicable to any other substrate material. Such ion‐milled waveguide lenses should facilitate realization of a variety of monolithically integrated optic device modules and circuits in GaAs and other related substrates with applications to communications, signal processing, and computing.

ISSN:0003-6951    

DOI:10.1063/1.100769

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Precise theoretical results of Maker fringes in biaxial crystals are presented which include such necessary corrections as absorption, finite beamwidth effects, and multiple reflections. Their applications to the new nonlinear optical material, organometallic complex crystal thiosemicarbazide cadmium chloride monohydrate (TSCCC, point groupCs‐m), and the corresponding experimental values of its six independent nonlinear optical coefficients are given.

ISSN:0003-6951    

DOI:10.1063/1.100770

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The TiN films have been prepared by photochemical vapor deposition using a D2lamp from a gas mixture of TiCl4‐NH3(or N2) ‐H2. The deposition temperature of the TiN films was lowered by 50–100 °C by irradiation with a D2lamp as compared to that without irradiation. The deposition rate was increased by 35–300% with irradiation.

ISSN:0003-6951    

DOI:10.1063/1.100771

出版商:AIP    

年代:1989

数据来源: AIP