Apparatus and Method for Varying a Bragg Wavelength of a Bragg Grating Formed in an Optical Fiber.
Patent Application, Filed 30 Jun 93,
DEPARTMENT OF THE NAVY WASHINGTON DC
Pagination or Media Count:
An apparatus and method uses a Bragg grating formed in the core of an optical fiber. An element is coupled to the optical fiber and serves to vary a Bragg wavelength i.e., a wavelength at which reflection occurs of the Bragg grating by varying a refractive index of the core andor a cladding of the optical fiber. The element can be an electro-optical element, a magnetooptical element or a chemo-optical element either sensing or being controllably varied, based on an electric signal, a magnetic signal or a presence or absence of a chemical, respectively. Alternatively, a dopant such as a rare-earth ion, can be formed in the core andor cladding of the optical fiber and irradiated with laser light from a laser pump. A change in absorption spectra from ground state absorption to excited state absorption changes the refractive index of the core andor cladding so that the Bragg wavelength of the Bragg grating is varied based on an intensity of the laser light.
- Fiber Optics and Integrated Optics