Showing papers on "Optical communication published in 1979"
Book•
01 Jan 1979
TL;DR: In this article, the authors present an overview of the literature in the field of fiber computing. But they do not discuss the theoretical aspects of fiber technologies. And they focus on the use of light-emitting Diodes (LEDs) for telecommunication.
Abstract: S.E. Miller, Overview and Summary of Progress. P. Kaiser and D.B. Keck, Fiber Types and Their Status. D. Marcuse, Selected Topics in the Theory of Telecommunications Fibers. S.R. Nagel, Fiber Materials and Fabrication Methods. C.H. Gartside III, P.D. Patel, and M.R. Santana, Optical Fiber Cables. S.C. Mettler and C.M. Miller, Optical Fiber Splicing. W.C. Young and D.R. Frey, Fiber Connectors. D.L. Philen and W.T. Anderson, Optical Fiber Transmission Evaluation. W.J. Tomlinson and S.K. Korotky, Integrated Optics: Basic Concepts and Techniques. W.J. Tomlinson, Passive and Low-Speed Active Optical Components for Fiber Systems. S.K. Korotky and R.C. Alferness, Waveguide Electrooptic Devices for Optical Communication. T.P. Lee, C.A. Burrus, Jr., and R.H. Saul, Light-Emitting Diodes for Telecommunication. J.E. Bowers and M.A. Pollack, Semiconductor Lasers for Telecommunications. S.R. Forrest, Optical Detectors for Lightwave Communication. K. Kobayashi, Integrated Optical and Electronic Devices. J.A. Long, R.A. Logan, and R.F. Karlicek, Jr., Epitaxial Growth Methods for Lightwave Devices. N.K. Dutta and C.L. Zipfel, Reliability of Lasers and LEDs. B.L. Kasper, Receiver Design. P.W. Shumate, Lightwave Transmitters. R.G. Swartz, High Performance Integrated Circuits for Lightwave Systems. P.S. Henry, R.A. Linke, and A.H. Gnauck, Introduction to Lightwave Systems. S.S. Cheng and E.H. Angell, Interoffice Transmission Systems. D.C. Gloge and I. Jacobs, Terrestrial Intercity Transmission Systems. P.K. Runge and N.S. Bergano, Undersea Cable Transmission Systems. P.E. White and L.S. Smoot, Optical Fibers in Loop Distribution Systems. I.P. Kaminow, Photonic Local Networks.
881 citations
TL;DR: In this article, the authors present a selective review of planar guided-wave acoustooptics, including some of the most recent results, focusing on those aspects which relate to wide-band multichannel optical communications and real-time signal processing.
Abstract: This paper presents a selective review of planar guided-wave acoustooptics, including some of the most recent results. The emphasis is on those aspects which relate to wide-band multichannel optical communications and real-time signal processing. First to be discussed are the analytical and numerical techniques required for the treatment of a Bragg modulator which uses a single aperture SAW transducer. The frequency responses generated for Y -cut LiNbO_3 waveguides using a digital computer serve as the basic data for the design of such a basic modulator. Next the key device parameters relevant to modulation and signal processing are discussed. The design parameters and procedures for wide-band Bragg modulators and deflectors are then established. Finally, some potential applications of such wide-band modulators and deflectors in optical communications and RF signal processing together with the best measured performance figures are described.
162 citations
TL;DR: In this paper, the response of a hybrid bistable optical device to step inputs of light was studied experimentally and the results confirm theoretical predictions concerning the dependence of switching time on the applied light increment.
Abstract: The response of a hybrid bistable optical device to step inputs of light was studied experimentally. The results confirm theoretical predictions concerning the dependence of switching time on the applied light increment. For the first time the phenomenon of ’’critical slowing down’’ is observed directly.
99 citations
TL;DR: In this article, a signal beam transmitted by a Fabry-Perot cavity is modulated by a control beam which changes the refractive index of the intracavity medium.
Abstract: A signal beam transmitted by a Fabry‐Perot cavity is modulated by a control beam which changes the refractive index of the intracavity medium. High finesse at the signal wavelength and strong absorption at the control wavelengths result in efficient optical gating and modulation. Such modulation has been observed using GaAs (and using color filters) with switch‐on times of 1 ns (10 μs) and switch‐off times of 2–20 ns (1 ms), and a physical length of only 5 μm (60 μm).
57 citations
TL;DR: In this paper, a single-mode c.w. operation at = 1.55 μm has been achieved in ridge-wavelength laser fabricated using InGaAsP quaternary alloys.
Abstract: Single-mode c.w. operation at =1.55 μm has been achieved in ridge-wavelength lasers fabricated using InGaAsP quaternary alloys. These lasers are promising candidates for future long-distance optical communications systems.
52 citations
Patent•
07 Nov 1979TL;DR: In this article, the core and the cladding of a single-mode optical fiber contain P2 O5 as a dopant selected to lower the deposition temperature and to hasten the deposition speed so as to result in low absorption loss.
Abstract: The invention relates to a single-mode optical fiber used in a long wavelength band range for optical telecommunication. The core and the cladding of this optical fiber contain P2 O5 as a dopant selected to lower the deposition temperature and to hasten the deposition speed so as to result in low absorption loss.
27 citations
Patent•
08 Nov 1979TL;DR: In this paper, an optical switch for changing over the mode connecting two optical transmission lines comprising two optical fibers directly to each other and an optical communication device between the two transmission lines is described.
Abstract: Disclosed is an optical switch for changing over the mode connecting two optical transmission lines comprising two optical fibers directly to each other and the mode connecting an optical communication device between the two transmission lines. In this optical switch, in order to reduce the insertion loss, first, second, third and fourth optical fibers, each having an optical connector attached to one end, are attached to a substrate so that at least parts of the respective optical fibers are fixed to the substrate, and the ends of the first and second fibers are arranged on the substrate movably so that the end face of the first optical fiber confronts the end faces of the second and third optical fibers and the end face of the second optical fiber confronts the end faces of the first and fourth optical fibers.
22 citations
TL;DR: A new type of optical switch is constructed of graded-index rod lenses operated mechanically by small electromagnets and has many outstanding features, such as low insertion loss, low crosstalk, and small size.
Abstract: A new type of optical switch is constructed of graded-index rod lenses. It is operated mechanically by small electromagnets. This switch is compatible with practical multimode-fiber communication systems. It has many outstanding features, such as low insertion loss (1.3–1.4 dB), low crosstalk ( 2 × 106 times), and small size (40 × 50 × 25 mm3).
20 citations
01 Jan 1979
TL;DR: The average bit error probability for a digital optical fiber system is numerically calculated using two receiver models and a Gaussian approximation of the statistics of the signal at the threshold detector input is introduced.
Abstract: The average bit error probability for a digital optical fiber system is numerically calculated using two receiver models. We analyze the influence of a number of important system parameters and of mBnB line coding. The decision threshold and the average avalanche gain are optimized to yield a minimum average bit error probability. Timing errors in the receiver are not considered, and we assume the shape of the received optical pulses to be known (rectangular or Gaussian). The equalization in the receiver is of the raised cosine type. A Gaussian approximation of the statistics of the signal at the threshold detector input is introduced. Average bit error probabilities are calculated using the exhaustive method. Koonen, A.M.J. ERROR PROBABILITY IN DIGITAL FIBER OPTIC COMMUNICATION SYSTEMS. Eindhoven University of Technology, Department of Electrical Engineering, Eindhoven, The Netherlands. September 1979. TH-Report 79-E-99 Present address of the author: Ir. A.M.J. Koonen, Philips' Telecornmunicatie Industrie B.V., Afd. Voorontwikkeling Transmissie, HUIZEN, The Netherlands
18 citations
Patent•
05 Sep 1979
TL;DR: In this article, the optical waves of both the modulation light and the local emission light are transmitted simultaneously within the same transmission medium to prevent the fluctuation of the frequency and the phase of the light.
Abstract: PURPOSE:To prevent the fluctuation of the frequency and the phase for both the modulation light and the local emission light by transmitting the optical waves of the both light simultaneously within the same transmission medium. CONSTITUTION:The output beam sent from laser device 11 is branched off (18) into the local emission light featuring the frequency of omega1 and containing no information signal and the modulation light obtained by modulating (12) the light of frequency omega0 by the information signal of frequency omegam. These two waves are then compounded (24) and applied to branching means 25 of the receiving side via transmission line 14. At the receiving side, both the local emission light and the modulation light are drawn out through filter 26 and 29. These light waves are compounded at compound means 32 and then put into heterodyne light detector 10. Thus, the beat signal is drawn out for the modulation light and the reference light.
16 citations
TL;DR: In this article, the design criteria for high-speed luminescent diodes are applied to realize InGaAsP/InP l.d at 1.26 μm wavelength.
Abstract: The design criteria for high-speed luminescent diodes are applied to realise InGaAsP/InP l.e.d.s at 1.26 μm wavelength. By highly doping the active region with Mg, a modulation bandwidth in excess of 1 GHz is achieved.
TL;DR: In this article, the possibility of using multimode instead of monomode optical circuits for application in optical communication systems is discussed and a modified, planar thick-film technology based on photosensitive sheets which is well suited to produce complicated multimode structures is presented.
TL;DR: In this article, a dual-wavelength light-emitting diode (LED) emitting near 12 and 13 μm has been fabricated for wavelength-multiplexed optical communication systems.
Abstract: A new dual‐wavelength light‐emitting diode (LED) emitting near 12 and 13 μm has been fabricated The differential efficiencies of the two outputs were 036 and 088%, respectively The intensities of these optical outputs can be controlled independently The optical cross talk between the two wavelengths was −10 and −16 dB at 115 and 135 μm, respectively This device is useful for wavelength‐multiplexed optical communication systems
TL;DR: In this article, a dual-channel 1.5 Mb/s lightwave receiver has been operated simultaneously with optical signals at two different wavelengths, and the effect of interchannel interference on error rate was measured.
Abstract: A dual-channel 1.5 Mb/s lightwave receiver has been operated simultaneously with optical signals at two different wavelengths. Two individually modulated InGaAsP/InP l.e.d.s provided optical signals at 10 and 1.18 μm wavelengths, and a new dual-wavelength photodetector served as a demultiplexing detector. The effect of interchannel interference on error rate was measured.
Patent•
13 Sep 1979TL;DR: In this article, a mode filter is inserted between a light source and an input of an optical fiber, which changes the phase of light to be propagated continuously or discontinuously so as to convert guided modes of lower azimuthal number into those of higher numbers in a light transmitting system.
Abstract: There is inserted between a light source and an input of an optical fiber a mode filter which changes the phase of light to be propagated continuously or discontinuously so as to convert guided modes of lower azimuthal number into those of higher numbers in a light transmitting system which employs a graded index optical fiber with a valley at the core-cladding boundary. This reduces the mode-delay differences for all modes including those which are close to cut off so that an optical communication system having a very wide bandwidth is obtained.
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TL;DR: The light emitting diode of chapter 2 can be modulated to act as the source in an optical communication system as mentioned in this paper, but the modulation bandwidth must be limited, so that different portions of the modulation spectrum do not arrive at different times at the receiver.
Abstract: The light emitting diode of chapter 2 can be modulated to act as the source in an optical communication system. The primary disadvantage of using an LED in such a system is that it emits light over a relatively wide range of wavelengths — the relative width of an LED’s emission is typically around 5 per cent. One effect of this rather broad spectral emission is that because of dispersion in the optical transmission path the modulation bandwidth must be limited, so that different portions of the modulation spectrum do not arrive at different times at the receiver. If an LED which has a peak emission at 600 nm with a 5 per cent spectral width is used as the source in an optical communication system, the bandwidth of the source is 25 000 GHz. Trying to modulate such a source is rather like superimposing modulation on noise.
TL;DR: In this paper, the authors investigated the transmission characteristics of analogue video signals by using semiconductor laser diodes and showed that the linearity degradation due to speckle noise depends on the optical-fibre types adopted.
Abstract: The transmission characteristics of analogue video signals are investigated by using semiconductor laser diodes. It is shown that the linearity degradation due to speckle noise depends on the optical-fibre types adopted. Based on this investigation, transmission over 32 km is carried out by using a 1·3 μm laser diode and single-mode fibres, with 46 dB unweighted s.n.r.
TL;DR: In this paper, a prototype fiber-optical communication line with spectral multiplexing in the 1.3μ region was developed using InGaAsP solid-solution heterolasers operating in the single-mode regime.
Abstract: A prototype fiber-optical communication line with spectral multiplexing in the 1.3μ region was developed. The use of InGaAsP solid-solution heterolasers operating in the single-mode regime made possible multiplexing with a spectral interval of 10 nm at the crosstalk level of less than –20 dB. The construction of a wavelength-division multiplexer, in the form of an autocollimation system with a diffraction grating and an objective, made it possible to achieve 25-fold spectral channel multiplexing in the line.
Journal Article•
Patent•
31 Oct 1979
TL;DR: In this paper, the optical signals from information source 1 and signal source 8 are combined via optical coupler 7 to be sent out to a piece of optical fiber, and the analog signal featuring a small amount of the leak noise is transmitted along with the digital signal through a simple circuit, shortening the necessary transmission band for the optical fiber.
Abstract: PURPOSE:To shorten the transmission band by combining the optical signals sent from the digital information source and the analog signal source via the optical coupler to send the combined signal to one piece of fiber and then transmitting the analog signal featuring a small amount of the leak along with the digital signal with a simple circuit. CONSTITUTION:Code converter 2 converts the digital signal sent from digital information source 1 in to such code as to feature the combination of the binary code pulses to give a fixed DC level to the digital optical signal. And the low frequency component contained in the transmitted digital optical modulation signal is removed through low band cut-of filter 3. Then the signals which are arranged to from the low frequency component region with elimination of the analog signal component are delivered from analog signal source 8. The optical signals from information source 1 and signal source 8 are combined via optical coupler 7 to be sent out to a piece of optical fiber. Thus the analog signal featuring a small amount of the leak noise is transmitted along with the digital signal through a simple circuit, shortening the necessary transmission band for the optical fiber.
IBM1
TL;DR: In this paper, the characteristics of double heterostructure stripe contact injection laser as they relate to applications in fiber optic data transmission systems are reviewed and the laser characteristics are treated as optical, electrical, thermal, and mechanical interfaces to the system.
Abstract: The characteristics of (GaAl) As double heterostructure stripe contact injection lasers as they relate to applications in fiber optic data transmission systems are reviewed. The laser characteristics are treated as optical, electrical, thermal, and mechanical interfaces to the system in order to emphasize the necessity of designing devices as a functional part of a system or subsystem. It is concluded that the laser is generally well suited as an optical source in a card-mountable hybrid module transmitter for data links up to a few km and ≅ 100 Mbit/s data rates. Areas requiring further development include lowering of the laser threshold current, improving the modal stability, packaging the laser with electronics and fiber optic transmission lines, and improving the laser lifetime under varying ambient temperature conditions.
TL;DR: In this paper, a phase-modulated optical carrier has been demonstrated over 500 m of graded-index optical fiber using a semiconductor-laser source and mode-mode interference.
Abstract: Reliable detection of a phase-modulated optical carrier has been demonstrated over 500 m of graded-index optical fibre using a semiconductor-laser source and mode-mode interference. The system performance is limited by the noise and spectral properties of the optical source. Spectral measurements indicate that transmission over several kilometres should be possible. This has direct significance for amplitude-modulated systems with semiconductor-laser sources as it implies that modal noise can occur at fibre connections up to several kilometres from the optical source
Patent•
07 Feb 1979
TL;DR: In this paper, a photo branching and coupling device of less insertion losses and crosstalk free from wavelength aberrations by using optical fibers, plane diffraction grating and concave reflecting mirror, in an optical communication system is presented.
Abstract: PURPOSE:To obtain the photo branching and coupling device of less insertion losses and crosstalk free from wavelength aberrations by using optical fibers, plane diffraction grating and concave reflecting mirror, in an optical communication system. CONSTITUTION:Optical fibers 1 consists of the 1st fiber which transmits light signal of plural wavelengths and plural optical fibers which transmit the specific wavelength light signal. The end part of the fibers 1 is disposed near the focus of a reflecting concave mirror 2. Now, the light containing multiple wavelengths emitted from the fibers 1 is reflected by the mirror 2, is diffracted by a diffraction grating 3, again returns to the mirror 2 and is received in the plural optical fibers with a slight change in position by each wavelength, whereby branching is completed. As a result of this, no wavelength aberrations exist because no lenses are used. In addition, the wavelength differences among channels may be taken smaller and crosstalk reduced as well.