摘要:

Shallow proton‐bombarded stripe‐geometry (5 &mgr;m wide, 380 &mgr;m long) lasers were fabricated from graded‐index waveguide separate‐confinement heterostructure (GRIN‐SCH) laser wafers grown by molecular beam epitaxy (MBE). Low median cw threshold currents of ∼50 mA were obtained for this stripe‐geometry gain‐guided structure. Such threshold currents represent a reduction by 25% from those of similar geometry lasers fabricated under the same technologies from the lowest threshold regular double heterostructure (DH) lasers wafers grown by MBE or liquid phase epitaxy (LPE). Up to the maximum measured output power of 10 mW/mirror (cw) the linearity is good and the symmetry of the output powers from both mirrors of these GRIN‐SCH (gain guided) lasers compares well to those lasers of the buried heterostructure type (index guided). The average intrawafer variation in the symmetry of the two end mirror outputs can be characterized by the average of the quantity ⟨&agr;⟩, which is the deviations from unity of theA/Bpower output ratio measured at 3 mW. For three LPE grown DH wafers ⟨&agr;⟩ is about ±20%, and varies from ±5% to ±8% for three MBE grown DH wafers. For three GRIN‐SCH wafers, ⟨&agr;⟩ between ±3% and ±0.8% was obtained. The standard deviations of the cw threshold current distributions for MBE grown lasers (&sgr;&bartil;4 mA dc) are one‐half that for LPE grown lasers. This documents the improved layer thickness and composition control achievable with the MBE growth procedure.

ISSN:0003-6951    

DOI:10.1063/1.94024

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

A new monolithic, diffraction coupled phase‐locked semiconductor laser array has been fabricated. Stable narrow far‐field patterns (∼3°) and peak power levels of 1 W have been obtained for 100‐&mgr;m‐wide devices with threshold currents as low as 250 mA. Such devices may be useful in applications where high power levels and stable radiation patterns are needed.

ISSN:0003-6951    

DOI:10.1063/1.94025

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The macrobend optical fiber tapped delay line is a new device which is ideally suited for the processing of signals that have very large bandwidths. Two new applications of this device are presented: code generation and matched filtering. An 8‐bit code at 1 Gbit/s was generated with a programmable eight tap delay line having 1‐ns tap intervals. Matched filtering at a rate of 1 Gbit/s was also demonstrated with a similar deivce. This letter presents the first fiber optic code generator/matched filter of its kind.

ISSN:0003-6951    

DOI:10.1063/1.94026

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

An ultraviolet laser photodeposition process based on the photolysis of TiCl4has been developed. The photochemistry of this new metal‐halide system has been shown to involve a surface‐catalyzed reaction confined to adsorbed molecular layers. By using this process, Ti films have been deposited on LiNbO3to form, after diffusion, 4‐&mgr;m‐wide single‐mode channel waveguides of comparable quality to conventionally fabricated Ti‐indiffused guides. The technique introduces new design flexibility into waveguide fabrication, permitting controlled gradations in the diffused index change and the lateral width along the guide.

ISSN:0003-6951    

DOI:10.1063/1.94027

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

A semiconductor interferometric laser with a resonator having curved and straight segments is reported. Interference is caused by internal reflection at the junction discontinuity between curved and straight segments due to a slight difference between the wave propagation constants. Lateral mode stability is provided by the fabrication of a buried heterostructure type laser cavity. The outstanding features of the laser are (1) very stable single longitudinal mode and stable lateral mode operation, and (2) a wavelength locking range of up to 23 °C within which the wavelength changes at a rate of 0.5–0.6 A˚/°C.

ISSN:0003-6951    

DOI:10.1063/1.94028

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Planar graded‐index SiO2optical waveguides characterized by very low scattering have been fabricated on silicon substrates by thermal oxidation. Three samples having thicknesses on the order of 15 &mgr;m are characterized by waveguide losses less than 1 dB/cm. The appearance of the waveguide streak and out‐of‐plane scattering measurements using photon counting indicate extremely low scattering. The low scattering along with the weak field confinement present in the graded‐index waveguides is consistent with the dominant waveguide loss being due to coupling to the silicon substrate.

ISSN:0003-6951    

DOI:10.1063/1.94029

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Low loss plastic optical fibers (POF’s) have been prepared employing a poly(methylmethacrylate‐d8) core and fluorinated alkyl methacrylate copolymer cladding with attenuation losses of 20, 25, and 50 dB/km at wavelengths of 660, 780, and 850 nm, respectively. These values were attained using the POF fabrication method which incorporates a closed polymerization and fiber drawing procedure. The POF can allow optical signal transmission over about 1300 m at −34 dBm at a rate up to 10 MHz using a display grade GaAlAs light‐emitting diode whose emission power at 660 nm and 20 mA of forward input current is 1 mW. The loss limit of this poly(methylmethacrylate‐d8) core POF is estimated to be 10 dB/km at 680 nm.

ISSN:0003-6951    

DOI:10.1063/1.94030

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Theoretical and preliminary experimental results are presented to demonstrate a new concept in optical information storage. The recording medium is a birefringent sheet of stretched polymer; the recording event is a modification of the birefringence by the action of heat, for instance, that generated by an absorbed laser pulse, or derived from contact with a heat source; the readout is based on the detection of changes in the state of polarization of a reading beam.

ISSN:0003-6951    

DOI:10.1063/1.94004

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

A conical transducer has been developed as an extension of the edge‐bonded transducer. Surface waves on the inside of a conical radiator are used to launch longitudinal waves in fluids. This transducer offers a broad bandwidth and low sidelobe levels.

ISSN:0003-6951    

DOI:10.1063/1.94005

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The study of indium implantation in silicon has gained considerable interest because of its potential in producing high value resistors in integrated circuits. We have studied the redistribution of indium as a function of high‐temperature anneal and dose. While the data show some anomalous redistribution, the bulk of the implanted indium remains undisturbed supporting a trapping mechanism during solid phase epitaxial growth for high‐temperature thermal anneals up to 1050 °C.

ISSN:0003-6951    

DOI:10.1063/1.94006

出版商:AIP    

年代:1983

数据来源: AIP