How is a Thin Film filter fabricated?（）
- A The glass core is doped with an Erbium in periodic segments of the fiber.
- B Layers of high index ?and low index ?material are deposited on a glass substrate.
- C Thin layers of silica glass are placed onto wafers to produce a prism-like effect.
- D Fiber is etched with an ultraviolet laser that is precisely spaced for specific wavelength filtering.