Chalcogenide Glasses

Preparation, Properties and Applications

J-L Adam, X. Zhang

• Publisher: Woodhead Publishing
• Year: 2014
• Print ISBN:
  9780857093455
• eBook ISBN:
  9780857093561
• Topic: Technology & Engineering
• Subtopic: Physical & Theoretical Chemistry
• Index: Technology & Engineering

The unique properties and functionalities of chalcogenide glasses make them promising materials for photonic applications. Chalcogenide glasses are transparent from the visible to the near infrared region and can be moulded into lenses or drawn into fibres. They have useful commercial applications as components for lenses for infrared cameras, and chalcogenide glass fibres and optical components are used in waveguides for use with lasers, for optical switching, chemical and temperature sensing and phase change memories. Chalcogenide glasses comprehensively reviews the latest technological advances in this field and the industrial applications of the technology.Part one outlines the preparation methods and properties of chalcogenide glasses, including the thermal properties, structure, and optical properties, before going on to discuss mean coordination and topological constraints in chalcogenide network glasses, and the photo-induced phenomena in chalcogenide glasses. This section also covers the ionic conductivity and physical aging of chalcogenide glasses, deposition techniques for chalcogenide thin films, and transparent chalcogenide glass-ceramics. Part two explores the applications of chalcogenide glasses. Topics discussed include rare-earth-doped chalcogenide glass for lasers and amplifiers, the applications of chalcogenide glasses for infrared sensing, microstructured optical fibres for infrared applications, and chalcogenide glass waveguide devices for all-optical signal processing. This section also discusses the control of light on the nanoscale with chalcogenide thin films, chalcogenide glass resists for lithography, and chalcogenide for phase change optical and electrical memories. The book concludes with an overview of chalcogenide glasses as electrolytes for batteries.Chalcogenide glasses comprehensively reviews the latest technological advances and applications of chalcogenide glasses, and is an essential text for academics, materials scientists and electrical engineers working in the photonics and optoelectronics industry. - Outlines preparation methods and properties, and explores applications of chalcogenide glasses. - Covers the ionic conductivity and physical aging of chalcogenide glasses, deposition techniques for chalcogenide thin films, and transparent chalcogenide glass-ceramics - Discusses the control of light on the nanoscale with chalcogenide thin films, chalcogenide glass resists for lithography, and chalcogenide for phase change optical and electrical memories

Part I

Preparation and properties of chalcogenide glasses

1

Preparation of high-purity chalcogenide glasses

V.S. Shiryaev; M.F. Churbanov Institute of Chemistry of High-Purity Substances of the Russian Academy of Sciences, Russia

Abstract

The methods of preparation of chalcogenide glasses for infrared fiber optics with low content of limiting impurities have been developed. The methods are based on solidification of glass-forming melts prepared by melting the initial high-purity elements in evacuated silica ampoule and purified additionally with chemical and distillation procedures. The effect of impurities (oxygen, hydrogen, carbon, sulfur, inclusions) on optical transmission of glasses was determined. The optical, thermal and crystallization properties of glasses were studied. Chalcogenide glass-based, low loss, multimode and single-mode optical fibers are produced with technical and operation characteristics sufficient for a number of cutting-edge applications. Factors affecting the optical absorption of glasses and optical fibers are analyzed.

Key words

chalcogenide glass

limiting impurities

chemical and distillation purification

optical transmission

low loss optical fibers

1.1 Introduction

Chalcogenide glasses are effective optical photonic materials. Chalcogenide glasses formed by individual chalcogenides of the III–V group elements of the Periodic Table or by their compounds have been known as optical materials for more than 50 years [1]. The first report on their application in fiber optics was published in 1965 [2, 3]. Active investigations of chalcogenide glasses as the materials for fiber optics in the middle infrared (IR) range have been carried out for the last 20–25 years [4–7]. A number of glasses with chalcogenides of III–V group elements were tested for production of optical fibers. The most important results were obtained for glasses based on chalcogenides of arsenic and germanium. These glasses have interesting properties, e.g. a wide transparency range, low optical losses, stability to atmospheric moisture, high non-linearity of optical properties, etc. There are a great number of technical problems in optics and optoelectronics which can be efficiently solved using chalcogenide optical fibers with low optical losses. The main efforts of researchers are directed to the increase of chemical and phase purity of glasses, to the development of optical fibers in view of special features of chalcogenide glasses, to investigation of the properties of glasses and optical fibers. This review presents the up-to-date status of developments of high-purity glasses from arsenic and germanium chalcogenides, as well as of optical fibers based on them.

1.2 Preparation of vitreous chalcogenides

Bulk samples of vitreous chalcogenides of arsenic and germanium of optical quality are produced by solidification of glass-forming melt. The initial charge of chalcogenide glass with a given composition is melted in evacuated sealed quartz ampoules. The melt solidification is carried out at time–temperature modes precluding crystallization, liquation and fluctuation of macro-composition. Being individual for different glass systems, these conditions are additionally governed by charge mass, glass and melt stability to crystallization and liquation. For example, the values for the critical cooling rate in vitreous As₂S₃ and As₂Se₃ differ by approximately three orders and are equal to 2.4 × 10⁻⁶ and 9 × 10⁻³ K/s, respectively [8].

The initial charge for the synthesis of glass-forming chalcogenides can be produced by different techniques [9, 10], i.e., from chemical elements (the traditional method); by decomposition of volatile inorganic compounds (hydrides, chlorides or iodides); via arsenic monosulfide for arsenic-containing components; or by deposition of chalcogenides from a solution.

Sulfide and selenide layers of arsenic and germanium can be produced by plasma chemical decomposition of hydrides and chlorides of these elements [5]. The advantage of this method is the lower rate of impurity income into the glass due to the lower temperature and shorter synthesis time as well as to the possibility to combine in one process the glass synthesis and production of preform for drawing optical fiber with a given index profile. A description is given in Refs [5] and [9] for production of glasses with GeS₂, GeSe₂, GeSe₃, Ge₂₇As₁₈Se₅₅, Ge₃₀As₁₅Se₅₅, and Ge₃₃As₁₂Se₄₅ composition by thermal decomposition of GeH₄, AsH₃, H₂Se, and H₂S mixtures. The produced glasses contained less than 0.1–0.3 ppm of transition metals and silicon impurities. The production of glasses of the Ge-Se system via chlorides by chemical vapor decomposition (CVD) is described in Refs [11] and [12]. Gaseous chlorides of glass elements together with H₂ passed in argon flow through the furnace heated up to 800 °C. Then the ampoule with deposited particles of Ge and Se is sealed off in a vacuum and synthesized. However, hydrogen and oxygen impurities are present in the sample transmission spectra. High content of hydro...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright page
• Contributor contact details
• Woodhead Publishing Series in Electronic and Optical Materials
• Part I: Preparation and properties of chalcogenide glasses
• Part II: Applications of chalcogenide glasses
• Index