Showing papers on "Fiber laser published in 1976"
TL;DR: The time dependence of the light backscattered within the fiber as the pulse travels down the waveguide is recorded and the total loss may be determined.
Abstract: Light from a pulsed GaAs injection laser is coupled into a glass fiber via a taper coupler. The time dependence of the light backscattered within the fiber as the pulse travels down the waveguide is recorded. From these data the total loss may be determined, as well as an estimate of the scattering and mode mixing characteristics of the fiber.
548 citations
Patent•
30 Mar 1976TL;DR: In this paper, an object-illuminating and imaging system utilizing, in combination, a laser beam as a light source and an optical fiber as light transmitter is presented. Light-focusing means are provided and the focused laser beam is, in a preferred embodiment of the invention, directed to impinge upon a single, small-diameter optical fiber.
Abstract: An object-illuminating and imaging system utilizing, in combination, a laser beam as a light source and an optical fiber as a light transmitter. Light-focusing means are provided and the focused laser beam is, in a preferred embodiment of the invention, directed to impinge upon a single, small-diameter optical fiber. Sensing means such as film or a television-type camera may be used visually to reproduce and/or display the illuminated object. A light-flow-disruptive means such as a vibrator, acting upon a collimated line of illumination, serves to reduce objectionable speckle effects ordinarily present in coherent light beams, thus providing enhanced clarity as viewed and in imaged reproductions.
130 citations
NEC1
TL;DR: In this article, a GaAs injection laser was proposed as a method for suppressing the relaxation oscillation of the light intensity in the cavity modes of a semiconductor laser under constant injection of external radiation into the cavity mode.
Abstract: Practical rates of direct pulse modulation of semiconductor lasers have so far been limited to below several hundred megahertz, owing to serious distortion in the output signal caused by the relaxation oscillation of the light intensity. Based on theoretical analysis of the dynamic properties of lasing under constant injection of external radiation into the cavity modes, light injection is proposed as a method for suppressing the relaxation oscillation. The effectiveness of this method has been confirmed in a series of preliminary experiments which employed GaAs injection lasers both as the modulated laser and as the external source of the injected radiation.
95 citations
TL;DR: In this paper, a single-crystal Nd:YAG fiber end-pumped by a single high-radiance LED was used to obtain the lowest cw laser threshold at a diode drive current of 45 mA.
Abstract: cw laser action has been obtained using as‐grown single‐crystal Nd:YAG fibers end‐pumped by a single high‐radiance LED. The fibers were 0.5 cm long and 80 μm in diameter, and the diameter of the LED luminous area was 85 μm. The lowest cw laser threshold was observed at a diode drive current of 45 mA.
76 citations
TL;DR: It is of interest to develop low insertion loss optical access couplers for interconnecting a number of spatially distributed terminals for serial distribution of data in a serial fashion using fiber bundles as a communication channel.
Abstract: There are currently strong trends in military system design, particularly shipboard and airborne, toward microminiaturization, digital processing, and system level integration to achieve smaller size, weight, and power consumption along with lower cost and improved reliability. Since these trends naturally point to data bus multiplexing, it is of interest to develop low insertion loss optical access couplers for interconnecting a number of spatially distributed terminals. Efforts to distribute data in a serial fashion using fiber bundles as a communication channel suffer from the packing fraction losses of the bundled fibers. The packing fraction loss is not a factor in systems employing single strands of fiber as a communication channel. As a result it is possible to utilize serial distribution for single-strand systems, provided that adequate techniques for coupling two single fibers together are developed. A promising approach is to fuse individual fiber waveguides together and control the coupling by controlling the coreto-core spacing and the interaction length. The guided optical modes in one fiber will then mix with those in another.
41 citations
Patent•
24 Nov 1976TL;DR: In this article, a stimulated Brillouin scattering (SBS) ring laser gyroscope is constructed from a single-mode optical fiber waveguide and is optically coupled to a laser to accommodate being pumped in two directions by laser radiation having sufficient energy to induce SBS.
Abstract: A stimulated Brillouin scattering (SBS) ring laser gyroscope. The SBS laser gyroscope is fabricated from a single-mode optical fiber waveguide and is optically coupled to a laser to accommodate being pumped in two directions by laser radiation having sufficient energy to induce stimulated Brillouin scattering radiation (SBS). The apparatus includes means for extracting a portion of each of the SBS radiation from the single-mode optical fiber waveguide and superimposing the extracted portions to permit detection of a beat frequency therebetween. The beat frequency detected is indicative of the rate of angular rotation of the area circumscribed by the single-mode optical fiber waveguide. Means are provided to accommodate a significant reduction in the required laser pumping power.
36 citations
TL;DR: In this article, the authors show that the reduction in visibility of the speckle pattern obtained from laser light that has been passed through a step-index light guide can be found from a knowledge of the model dispersion of the guide, and the bandwidth of the laser beam.
Abstract: We show that the reduction in visibility of the speckle pattern obtained from laser light that has been passed through a step-index light guide can be found from a knowledge of the model dispersion of the guide, and the bandwidth of the laser beam.
36 citations
TL;DR: In this article, the stimulated emission cross-section σ and fluorescence lifetime for the 1.06 μm emission (4 F 3/2 → 4 I 1/12 ) have been measured for a number of Nd-doped tellurite glasses.
22 citations
23 Jul 1976
TL;DR: The application of the optical fiber waveguides to laser gyroscopes is divided into two sections: 1) The ring interferometer and 2) the ring laser.
Abstract: The application of the optical fiber waveguides to laser gyroscopes is divided into two sections: 1) The ring interferometer and 2) The ring laser. Experiments show that a well defined, stable interference pattern can be obtained using a single mode fiber. This together with the experimentally obtained coupling efficiency of laser radiation into the fiber (-50%) indicate that in addition to a sensitive ring interferometer gyroscope a ring laser gyroscope can be built using a single mode fiber waveguide as the passive part of the laser cavity.© (1976) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
15 citations
Patent•
22 Dec 1976TL;DR: In this paper, the authors presented a method for synthesizing laser light characterized by a plurality of discrete wavelengths, without competition among different wavelengths. But their method was not suitable for the use of laser resonators, and the resulting laser beam appeared white in color.
Abstract: Apparatus and method for synthesizing laser light characterized by a plurality of discrete wavelengths, without competition among different wavelengths. A preferred embodiment of the invention includes a laser resonator having an optical cavity bounded by a first, reflective end plate; a gas-filled chamber having a pair of Brewster windows, within the optical cavity; and a Brewster angle Pockels cell between one Brewster window and the partially reflective end plate. The laser resonator generates red, blue and green laser light simultaneously and the Pockels cell transmits red, blue and green light successively, at a rate of at least 30 cycles per second, so that the resulting laser beam appears white in color.
14 citations
TL;DR: In this paper, the relation between the peak photon number in the onset of relaxation oscillations of lasers and the injected photon number is shown, and the step response of the CW laser to the external signal injection and the reshaping property of the laser for the distorted optical pulse are reported.
Abstract: The rate equation including the injection term was extended and solved numerically. The relation between the peak photon number in the onset of relaxation oscillations of lasers and the injected photon number is shown. The step response of the CW laser to the external signal injection and the reshaping property of the laser for the distorted optical pulse are reported.
01 Jan 1976
TL;DR: In this paper, the modulation characteristics of contemporary cw junction lasers with a view to identifying current limitations on their performance are discussed, focusing on the (AlGa)As double-hereto-structure (DH) diode fabricated in a stripe-geometry since this device is the most developed for fiberguide systems.
Abstract: Lightwave communication systems employing junction lasers as sources are currently being evaluated in realistic field environments around the World. In many respects, a laser diode is an ideal source for these systems since it emits adequate power for economical fiberguide transmission and is compatible with fibers integrated optics, and integrated circuits, efficient in its conversion of electrical to optical power, mechanically rugged, potentially reliable, and easily modulated in a variety of ways. This paper reviews the modulation characteristics of contemporary cw junction lasers with a view to identifying current limitations on their performance. We focus on the (AlGa)As double-hereto-structure (DH) diode fabricated in a stripe-geometry since this device is the most developed for fiberguide systems.
TL;DR: For use in absorption measurements in low-attenuation glass fibers, the periodic temperature rise at the surface of a glass cylinder heated by a chopped laser beam is calculated.
Abstract: For use in absorption measurements in low-attenuation glass fibers, we calculate the periodic temperature rise at the surface of a glass cylinder heated by a chopped laser beam. Specifically, we give the mean temperature, setting the operating temperature of the experiment, and the peak-to-peak temperature, determining the sensitivity of the measurements.
Patent•
05 Apr 1976
TL;DR: In this article, the diameter of an optical fiber was uniformalized by controlling the fiber diameter in accordance with the measured level of the variation in the diameter in a preform.
Abstract: PURPOSE:To uniformalize the diameter of an optical fiber by controlling the fiber diameter in accordance with the measured level of the variation in the diameter of a preform.