| 摘要 |
<p>A ceramic material has a thermal expansion coefficient of 50 x 10-7 / °C or less, an absolute value of the difference between the relative refractive indexes of silica glass and the ceramic material of 0.2 or less at a wavelength of 1550 nm, and a light attenuation coefficient of 0.3 dB/cm or more.</p> |
