Showing papers on "Guided wave testing published in 1976"
TL;DR: In this article, the evanescent part of a guided wave was used as the reference wave and/or the illuminating one to reconstruct a wave-guide hologram from a plane reference wave.
87 citations
TL;DR: In this article, a guided wave was radiated as the leaky wave which appears selectively either above or below the grating depending on the direction of the propagation of the guided wave.
Abstract: High‐efficiency blazed grating couplers have been successfully realized by using an ion etching technique. We observed that a guided wave was radiated as the leaky wave which appears selectively either above or below the grating depending on the direction of the propagation of the guided wave. The coupling efficiency from the guided wave into one of the leaky waves was about 97% at the blaze angle of 30°.
83 citations
PARC1
TL;DR: In this paper, an equation for TM-mode coupling coefficients in DFB-based double-heterostructure GaAs with rectangular, triangular, and sawtooth-shaped teeth was derived.
Abstract: An equation is derived for TM-mode coupling coefficients in guided-wave distributed feedback (DFB) lasers. Results for GaAs:GaAlAs double-heterostructure lasers with rectangular, triangular, and sawtooth-shaped teeth, various Bragg diffraction orders, and transverse mode numbers are presented for TM modes and compared with those for TE modes. Generally, but not always, coupling coefficients for TE modes exceed those for TM modes.
74 citations
01 Mar 1976
TL;DR: Guided-wave acoustooptic Bragg diffraction from a single surface acoustic wave (SAW) and from two tilted SAW's has been analyzed to establish the design parameters of the related devices.
Abstract: Guided-wave acoustooptic Bragg diffraction from a single surface acoustic wave (SAW) and from two tilted SAW's has been analyzed to establish the design parameters of the related devices. Design and performance figures of the devices involving three and four tilted SAW's in single-mode Y-cut LiNbO 3 out-diffused waveguides are described in detail. Device bandwidth of up to 358 MHz, an optical throughput coupling efficiency of up to 25 percent, and very good optical beam quality have been realized. A bandwidth of 358 MHz enables the device to deflect a light beam of 1-cm aperture into 1000 resolvable spot diameters with a random-access switching time of 2.8 µs. A total electric drive power of 220 mW was required to diffract 50 percent of the incident light power for the unit with 245-MHz bandwidth. The development of this wide-band technique has paved the way for using such guided-wave acoustooptic devices in a number of applications in addition to those common to bulk-type acoustooptic devices.
51 citations
01 May 1976
TL;DR: In this article, a unified theory was developed to treat wide-band AO interaction configurations involving multiple-tilted and phased-SAW's or a combination of both, and design, evaluation, and pedormance of a number of AO scanning devices using the first two configurations in LiNbO 3 out-diffused waveguides are presented.
Abstract: Some key results of a unified theory which has been developed to treat wide-band guided-wave AO interaction configurations involving multiple-tilted and phased-SAW's or a combination of both are reported. Design, evaluation, and pedormance of a number of AO scanning devices using the first two configurations in LiNbO 3 out-diffused waveguides are presented. A number of potential applications of such wide-band devices are discussed together with some preliminary performance figures.
26 citations
TL;DR: In this article, a new theoretical method using path integrals is applied to this problem and avoids the use of modes, and in some cases compact analytical expressions for the field or the impulse response are obtained.
Abstract: In a stratified wave guiding system the propagation of electromagnetic waves is usually described by the use of modes. This method however involves summations which are a formidable task if many modes are excited and attenuated equally. A new theoretical method using path integrals is applied to this problem and avoids the use of modes. As a consequence large summations are avoided and in some cases compact analytical expressions for the field or the impulse response are obtained.
22 citations
Patent•
10 Mar 1976TL;DR: A thin-film optical switching device has a substrate of fused quartz, an optical slab waveguide or Corning glass No. 7059, a thin film crossing a portion of the length of the waveguide, and an interdigital transducer on the substrate for generating an elastic surface wave to propagate it through the thin film as discussed by the authors.
Abstract: A thin-film optical switching device has a substrate of fused quartz, an optical slab waveguide or Corning glass No. 7059, a thin film crossing a portion of the length of the waveguide, and an interdigital transducer on the substrate for generating an elastic surface wave to propagate it through the thin film. The optical waveguide, and thin film have respective parameters such that almost all energy of an optically guided wave and the elastic surface wave are concentrated into the thin film while the optically guided wave within the thin film undergoes acousto-optical interaction, that is, Bragg diffraction.
19 citations
TL;DR: In this article, experimental demonstration of four potential applications using wideband guided-wave acousto-optic Bragg-devices which utilize multiple-tilted surface acoustic waves is presented.
Abstract: This paper consists of two major parts: (1) experimental demonstration of four potential applications using wideband guided-wave acousto-optic Bragg-devices which utilize multiple-tilted surface acoustic waves, (2) preliminary results on two new guided-wave electro-optic devices, using simple tilted-electrode and apodized-electrode array structures, respectively. Excellent performance figures with the two categories of devices, using Y-cut LiNbO3 waveguides, have been achieved. The devices should be suited for many applications in future wideband fiber and integrated optic systems.
14 citations
TL;DR: In this paper, the effect of material absorption loss on grating-coupler performance was examined and it was shown that a total field decay constant α T must be used in place of the leaky wave contant α whenever loss is appreciable.
Abstract: The effect of material absorption loss on grating-coupler performance is presented. In particular we examine grating couplers fabricated holographically in photoresist. It is shown that a total field decay constant α T must be used in place of the leaky wave contant α whenever loss is appreciable. This total rate of field decay α T can be obtained, to a good approximation, by adding an absorption loss factor α abs to the leaky wave constant α. The absorption rate α abs is calculated by considering a suitable equivalent uniform waveguide and the leaky wave constant α is obtained by neglecting all loss in the structure except that due to beam radiation. Guided wave attenuation is found to be due almost entirely to absorption in the residual resist layer left between the grating and the waveguide rather than to absorption in the grating teeth. Experiments demonstrate that grating couplers fabricated in Shipley AZ 1350B photoresist have measured properties in agreement with the lossy description described above.
9 citations
TL;DR: In this article, a four-port microwave-integrated-circuit (MIC) edge-guided wave circulator (BGC) was designed, fabricated, and tested, and a mathematical characterization of the strip conductor's shape as well as a precise mechanical control of the bias inhomogeneity were provided.
Abstract: Four-port microwave-integrated-circuit (MIC) edge-guided wave circulators (BGC) have been designed, fabricated, and tested. A mathematical characterization of the strip conductor's shape as well as a precise mechanical control of the bias inhomogeneity are provided. By means of these two techniques the reproducibility of the device is greatly improved with respect to that of the EGC obtained by the traditional cut-and-try methods. X-band performance data are presented and related to the spatial distribution of the effective magnetic permeability mu/sub eff/ in the ferrite substrate. Experimental evidence is reported that an efficient circulator action occurs when mu/sub eff/< 0 at some point under the central circular shield. The spatial distribution of the RF electric field at the circulator's surface is investigated by a mechanical probing technique. It is found that in the lower part of the operation band, RF fields of considerable amplitude extend in the air in the region between the guiding edge and the substrate's edge.
8 citations
TL;DR: In this paper, an equivalent model is presented for evaluating the fringing-field effects in edge-guided waves (EGW) propagating along ferrite microstrip circuits, based on the approximate model developed by Getsinger for nonferromagnetic micro strip circuits.
Abstract: An equivalent model is presented for evaluating the fringing-field effects in edge-guided waves (EGW) propagating along ferrite microstrip circuits. It is based on the approximate model developed by Getsinger for nonferromagnetic microstrip circuits. Fringing-field effects are characterized by a fringing-field parameter b/b' whose numerical value is determined by experiment. Measurements are made on EGW resonators of various shapes for different values of the applied magnetic bias. Finally, the fringing-field parameter is used to evaluate the ratio between the reactive power stored in the fringing fields and the RF power in the ferrite under the strip conductor in a disk resonator.
01 Jan 1976
TL;DR: In this article, experimental results of a directional coupler, fabricated by ion implantation through a conventionally produced photoresist mask into fused quartz, are discussed and the dependence of the coupler on various technological parameters is given and the use as a frequency selective element is experimentally demonstrated.
14 Jun 1976
TL;DR: In this article, a real-time processing of rf signals using guided-wave acoustooptic Braggdiffraction in LiNbO/sub 3/ waveguides has been studied both theoretically and experimentally.
Abstract: Real-time processing of rf signals using guided-wave acoustooptic Bragg-diffraction in LiNbO/sub 3/ waveguides has been studied both theoretically and experimentally. Good performance figures for convolution have been achieved by employing multiple tilted surface acoustic waves: time-bandwidth product of 305, dynamic range of approximately 50 db, total rf power of 310 mW for maximum convolution output and the frequency resolution of 1 MHz (defined at zero convolution output).
Journal Article•