Do you use a laser like a CNC engraving machine to “carve” the grating into the fiber?
The process of UV writing for Fiber Bragg Gratings (FBG) is different from the mechanical or thermal “carving” seen in CNC engraving. While it does involve a laser, it is a photochemical process rather than a physical removal of material.
Technical Explanation: How UV Writing Works
In FBG manufacturing, we do not physically “carve” or engrave the glass. Instead, we use Photosensitivity.
- The Material: The core of the optical fiber is typically doped with Germanium (Ge). This makes the glass “photosensitive.”
- The Laser: We use high-intensity Ultraviolet (UV) light (typically from an Excimer laser or a Frequency-Doubled Argon-ion laser).
- The Process: When the fiber core is exposed to a specific interference pattern of UV light (created using a Phase Mask), the refractive index of the Germanium-doped glass changes permanently in those specific areas.
- The Result: This creates a periodic modulation of the refractive index inside the core. This “internal pattern” is the grating.
Because the change happens at the atomic level within the glass structure, the physical surface of the fiber remains smooth and intact, which is critical for maintaining the fiber’s mechanical strength.
OFSCN® Product Implementation
At Beijing Dacheng Yongsheng Technology Co., Ltd. (OFSCN), we utilize this UV writing technology to produce high-performance FBG sensors. Our expertise lies in how we protect these “written” gratings for harsh environments.
For example, after the UV writing process, we can package these fibers into specialized housings:
- OFSCN® Capillary Seamless Steel Tube FBG Temperature Sensor: This uses a seamless steel tube to protect the UV-written grating, allowing for temperature measurements in demanding industrial settings.
- OFSCN® High Temperature Resistant Fiber Bragg Grating (FBG): We use advanced grating writing and annealing techniques to ensure the “UV-written” pattern does not fade even at elevated temperatures.
Standard Production Layout:
To better understand the application, are you looking into the manufacturing process for research purposes, or are you looking for a specific sensor for a project?