transparent glass ceramics of low expansion glass ceramics substrate for optical wellenleiterelement and

摘要

There are provided low expansion transparent glass-ceramics obtained by heat treating a base glass produced at a relatively low melting temperature of 1530 DEG C or below. The glass-ceramics have an average linear thermal expansion coefficient within a range from +6 x 10-7/ DEG C to +35 x 10-7/ DEG C, 80% transmittance wavelength (T80) of 700nm or below. internal transmittance of 75% or over at light wavelength of 1550nm, heat resisting temperature of 800 DEG C or over.and Young's modulus of 90 GPa or over. The glass-ceramics comprise SiO2, Al2O3, MgO, CaO, BaO, ZnO, Li2O, TiO2 and ZrO2 and contain beta -quartz or beta -quartz solid solution as a predominant crystal phase. There are also provided optical waveguide elements and an arrayed waveguide grating (AWG) type planar lightwave circuit utilizing these glass-ceramics.