| 摘要 |
PURPOSE:To mass-produce low-loss band-pass filters by connecting different- length fibers, obtained by making two holes at close positions along the axis of a glass bar and by inserting and drawing glass bars higher in refractive index so that only either one of cores will be connected. CONSTITUTION:Along the axis of a quartz bar, two holes are made at close positions, and quartz bars made higher in refractive index than the said quartz bar by adding additives are inserted and drawn to obtain fibers 1-3 having two kinds of cores 1A and 1B-3A and 3B with properly selected lengths L1-L3. Those cores 1B and 2B, and 2B and 3A are connected together coaxially. Cores 1A-3A are those where lights penetrating the filter pass, and cores 1B-3B are those to which the lights penetrating this filter are emitted by being divided according to the wavelength. Thus, low-loss band-pass filters can be mass-produced. |
