| Project/Area Number |
16560596
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Inorganic materials/Physical properties
|
|---|
| Research Institution | National Institute for Materials Science |
|---|
Principal Investigator |
TODOROKI Shin-ichi National Institute for Materials Science, Advanced Materials Laboratory, Senior Researcher, 物質研究所, 主幹研究員 (40343876)
|
|---|
| Project Period (FY) |
2004 – 2005
|
| Project Status |
Completed (Fiscal Year 2005)
|
| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2005: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2004: ¥2,300,000 (Direct Cost: ¥2,300,000)
|
|---|
| Keywords | Optical fiber / Soft glass / plastic flow / Optical switch / Thermal stability / 光フアイバ / 結晶化 |
|---|
| Research Abstract |
The recent development of laser light sources of over 1 kW has stimulated the need for the devices called optical fuse/limiter which are used for protecting optical systems from unexpected incident light. I have proposed another type of fiber-based optical fuse, in which a transparent soft glass layer (tellurium oxide) is inserted across the fiber circuit and coated with carbon paint. The breakdown is accomplished by the following process ; (1)A small portion of light propagating in the soft glass reaches the outer carbon coating since the glass layer does not include a waveguide structure. (2)The coating absorbs the non-guided light and this increases its temperature. (3)The adjacent soft glass layer is also heated and deforms or devitrifies thus breaking the optical connection. This device can endure few watts of light but its response time is more than 0.1 sec. Such a slow response is attributed to the speed of thermal diffusion and plastic flow during the reaction. Therefore, here I report the dynamics of the heat-induced deformation of a soft glass layer by monitoring its insertion loss.
The irreversible transformation of a tellurium oxide glass layer inserted between two ends of two silica glass optical fibers was monitored via the intensity of a light passed through the circuit. Heat-induced breakage occurred when the glass crystallized or flowed in the presence of a shearing stress. Without the stress, the optical link was maintained through the glass melt but suddenly broke due to the crystallization. On the other hand, the stress deformed the glass bridge and broke the optical link less than 0.4 sec. Thus, the shearing stress at the splicing point helps the device respond immediately and reliably.
|
