Crystallized glass

Abstract

A glass-ceramics which deposits [beta]-quartz solid solution or [beta]-eucryptite solid solution as a primary crystal, has a degree of crystallinity of 70 mass % or more and a crystal grain diameter of 0.5 [mu]m or less, is substantially free from the presence of a clearance or crack in a grain boundary, has a thermal expansion coefficient in the range of -40 1 / 2 C to 100 1 / 2 C of -10 X 10<-7> / 1 / 2 C or greater in minus, a hysteresis of thermal expansion in the above temperature range of 10 ppm or less, and a temperature dependence of refractive index (dn / dT) of 13 X 10<-6> / 1 / 2 C or less.

Description

technical field [0001] The present invention relates to the invention of crystallized glass that precipitates β-quartz solid solution or β-eucryptite solid solution as the main crystal, and in particular relates to waveguide layer materials suitable for waveguide devices in the field of optical communications and temperature compensation for various devices Crystallized glass as substrate material. Background technique [0002] As is well known, in the past, crystallized glass with precipitated β-quartz solid solution or β-eucryptite solid solution as the main crystal and an expansion coefficient close to zero has been used in various fields such as furnace window glass and building fireproof glass. [0003] However, in recent years, with the development of optical communication technology, networks using optical fibers have been gradually completed. In such a network, multiple technologies that transmit multiple wavelengths of light at a time are gradually used, and filter...

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Problems solved by technology

[0011] On the other hand, the FBG is a device that forms a lattice-shaped refractive index change portion, that is, a grating, in the core part of an optical fiber, and is characterized by reflecting light of a specific wavelength. As shown in the formula, changes in the refractive index and lattice spacing will cause changes in the reflected wavelength

Even if a material with a large thermal expansion hysteresis is used as a temperature compensation material, the temperature dependence of the device cannot be compensated correctly

[0024] WO97 / 28480 describes a method of repeatedly performing heat treatment in the temperature range of 400 to 800°C for the purpose of reducing the thermal expansion hysteresis of crystallized glass. However, such heat treatment leads to a significant decrease in productivity and an increase in cost. the occurrence of problems

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