MetglasTM 2605 SC cast alloy was deposited directly onto single-mode optical fibers. Very thick amorphous films of 5 to 15 micrometers thickness were produced by triode-magnetron sputtering. The coated fibers were used as magnetic field sensing elements in one arm of a Mach-Zehnder interferometer. In the reference arm a section of fiber was wound around a piezoelectric (PZT) cylinder which was driven by a feedback correction signal to keep the sensor operating at quadrature. The sensing element was placed inside a chamber containing Helmholtz coils which produced both a dc field and an ac dither field. The magnetostructure response of the coating and the resulting phase shift in the optical fiber are dependent upon both of these fields. The phase shifts were measured as a function of the magnitudes of the dc and ac fields and the frequency of the ac field. The magnetostrictive responses had maximum values at discrete resonance frequencies. Experimental values of the magnetostriction parameter were obtained using experimental values of the phase shifts along with theoretical calculations of the magnetostrictive response. These calculations were based on a model of coherent rotation of magnetization and also an elastic model of the magnetostrictive strains for a cylindrical geometry. The maximum values of the magnetostriction parameter for the coated- fiber FOMS at resonance was estimated to be 10-5/Oe2 in comparison with non-resonant values of 5X10-5/Oe2 and 1X10-6/Oe2 for amorphous metal wire transducers and Metglas strip transducers, respectively, and 5X10-6/Oe2 for resonant Metglas cylindrical transducers.

Gas flow rates can be measured with a hot-wire anemometer which employs a fine wire mounted transversely to the gas flow. The wire is heated by an electrical current and the temperature rise, which depends inversely on the flow rate, is determined by the resistance change of the wire. In the optical fiber anemometer the fine wire is replaced by a short segment of gold-coated single-mode optical fiber which forms one arm of an all-fiber Mach-Zehnder interferometer. The gold coating is 0.1 pm thick and covers a 1 cm length of the unjacketed silica fiber; this coated section is mounted transversely within a 1 cm diameter tube through which nitrogen gas flows. The fiber is heated by applying a 5 sec voltage pulse to the gold coating. The increase in the temperature results in an increase in both the length and refractive index of the fiber core, and a corresponding increase in the phase of the light propagating through the sensing arm of the interferometer. The magnitude of this phase change, which is determined by fringe counting, is used to determine the temperature change and hence the flow rate. Convective heat transfer coefficients were determined for the low flow rates (0-2 m/sec) employed in these experiments. The experimental results are in excellent agreement with previous experimental results on low-velocity forced convection. In general the device can measure gas flows with greater precision than a conventional hot-wire device.

GaAs is a very attractive material for use at the 10.6-μm wavelength of the CO2 laser, and very little work has been done at this wavelength. This paper discusses recent investigations with n/n+-GaAs rib waveguides fabricated by molecular beam epitaxy and reactive ion etching. A simple effective index method of analysis was performed to predict the propagation constants of the bound modes. Comparison with other methods of analysis has shown this method to be fairly accurate for the geometries used. The prism-coupling technique was modified for rib waveguides. Experimental intensity curves as a function of incident angle (Θ) correlated well with the theoretical lower order modes.

Amorphous films 3.5 μm thick of Fe81B13.5Si3.5C2 were deposited using conventional radio-frequency sputtering on planar glass substrates and cladded single-mode optical fibers of 80-μm diameter with a core diameter of 4 μm. The substrates were arranged in two configurations. In the first configuration the substrates (group I) were placed in contact with the water-cooled substrate table; in the second configuration (group II) the substrates were suspended about 8 mm above the substrate table. Ferromagnetic resonance (FMR) and vibrating sample magnetometer (VSM) measurements were used to study the bulk properties of the film and the longitudinal magneto-optical Kerr effect was used to study the magnetic hysteresis at the film surfaces. The group (I) samples were found to be magnetically softer than their group (II) counterparts. The magnetostrictive response of the coated fibers was studied using a Mach–Zehnder interferometer. The dependence of this response on annealing is also discussed.

Proton bombardment of doped gallium arsenide is known to produce electrical compensation and optical changes within the implanted material. In semi-conductor processing this technique has found wide application ranging from electrical device isolation to laser fabrication. This paper addresses recent advances in this technology with emphasis on opto-electronic developments. Components and devices formed through this process are reviewed as well as the optical and electrical properties of the bombarded material.

Samples of n+-GaAs implanted with 300 keV protons have been examined using high resolution electron microscopy, capacitance-voltage profilometry, and infrared reflectance. In contrast to previously reported results, electron microscopic examination of the as-implanted samples revealed the presence of dislocation loops and/or precipitates both near the wafer surface and at the bottom of the implanted layer. These results are corroborated by electrical and optical measurements.

Ion implantation of semiconductor materials is a very attractive technique for forming the guided wave components needed in integrated optical circuits. However, to produce optical components with sufficiently deep implanted regions for low loss operation at a wavelength of 10.6 microns, this technique normally requires very high accelerating energies, in excess of 1 MeV. Here we report on a series of experiments exploring an alternative solution to this requirement, namely, the migration of optically active carrier compensating centers produced by implantation at both elevated and cryogenic temperatures. While this mechanism has been observed in the formation of p-n junctions in GaAs, no attempt has previously been made to utilize this enhanced penetration for optical waveguidin:E. Silicon-doped n-type GaAs wafers have been implanted with 300 keV protons at fluence levels up to 5x1015 ion/cm2. During implantation, the wafers have been maintained at temperatures ranging from -170°C to +350°C. The thickness of the compensated region has been determined from infrared specular reflectance curves and from capacitance voltage (C-V) measurements. Theoretical reflectance curves are constructed based on the thickness data and are compared to the experimental curves.© (1981) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Surface layers capable of supporting optical modes at 10.6 microns have been produced in n-type GaAs wafers through 300 keV proton implantation. The dominant mechanism for this effect appears to be free carrier compensation. Characterization of the implanted layers by analysis of infrared reflectivity spectra and synchronous coupling at 10.6 microns produced results in good agreement with elementary models. These results of sample characterization by infrared reflectivity and by CO2 laser waveguiding as implanted are presented and evaluated.

The electric conductivity of metal-p-quaterphenyl-metal thin polycrystalline layers sandwich structures have been investigated as a function of voltage, thickness, and temperature. The films which ranged in thickness from 0.9 to 1.6 μm were measured in the temperature range of 100–370 K. The experimental data may be explained by space charge effects with contribution of Richardson—Schottky mechanism or in terms of injection modified by space charge effects.

In the present study, Zinc Telluride (ZnTe) thin films (650–7700 Å) were prepared on the well-cleaned glass substrates under the pressure of 10-5 m.bar by thermal evaporation method. The thickness of the film was measured by multiple beam interferometer (MBI) technique. Al-ZnTe-Al sandwich structure was fabricated to study the transport properties. DC conduction studies on these films were carried out using digital pico ammeter in series with capacitor and voltage source for different temperatures (303–483 K). Ohmic and non-ohmic conduction mechanisms were observed at all temperatures in the low and high fields respectively. Observed non-ohmic conduction has been explained on the basis of Poole–Frenkel effect. The estimated activation energy lies between 0.15 and 0.25 eV and found to decrease with increase in film thickness.

Field-induced switching between two impedance states has been observed in both pure and doped organic thin films. Aromatic hydrocarbon films display this phenomenon reproducibly when a mobile electrode material such as gallium-indium alloy is employed. Controlled doping of the hydrocarbons with electron acceptors leads to reproducible switching characteristics which are not electrode dependent. For the doped films, activation energies of conduction typical of bulk charge-transfer complexes characterize the low impedance states whereas the activation energies of the high impedance states are typical of organic insulating films. It is suggested that the switching mechanism involves the formation of conducting filaments.