A method for producing a protected optical fiber with distributed sensors includes heating an optical fiber preform and drawing the heated optical fiber preform to form a drawn optical fiber. The method also includes coating the drawn optical fiber with a carbon coating after the optical fiber is drawn to provide a carbon coated optical fiber and then writing a series of fiber Bragg gratings (FBGs) into the carbon coated optical fiber to provide a carbon coated optical fiber with FBGs. The method further includes coating the carbon coated optical fiber with FBGs with one or more layers of a polymer to provide the protected optical fiber with distributed sensors, wherein the heating, drawing, carbon coating the drawn optical fiber, writing, coating the carbon coated optical fiber are performed in that sequence while the protected optical fiber is being produced.

Improved Raman Fiber Laser (RFL) generators may include a mid-infrared fiber, e.g., a fiber comprising a tellurite glass, a chalcogenide glass, a fluoride glass, or similar material. A phase-shifted fiber Bragg grating may be inscribed in the fiber. A pump laser generator may be coupled with the fiber in order to supply a pump laser to the fiber. When stimulated by the pump laser, the RFL generator may emit an output laser having a mid-infrared wavelength. A tuner may be used to tune the output laser.

Techniques are described for using confinement structures and/or pattern gratings to reduce or prevent the wicking of sealant polymer (e.g., glue) into the optically active areas of a multi-layered optical assembly. A multi-layered optical structure may include multiple layers of substrate imprinted with waveguide grating patterns. The multiple layers may be secured using an edge adhesive, such as a resin, epoxy, glue, and so forth. A confinement structure such as an edge pattern may be imprinted along the edge of each layer to control and confine the capillary flow of the edge adhesive and prevent the edge adhesive from wicking into the functional waveguide grating patterns of the layers. Moreover, the edge adhesive may be carbon doped or otherwise blackened to reduce the reflection of light off the edge back into the interior of the layer, thus improving the optical function of the assembly.

Improved Raman Fiber Laser (RFL) generators may include a mid-infrared fiber, e.g., a fiber comprising a tellurite glass, a chalcogenide glass, a fluoride glass, or similar material. A phase-shifted fiber Bragg grating may be inscribed in the fiber. A pump laser generator may be coupled with the fiber in order to supply a pump laser to the fiber. When stimulated by the pump laser, the RFL generator may emit an output laser having a mid-infrared wavelength. A tuner may be used to tune the output laser.

Provided are an apparatus for manufacturing a grating and a method for manufacturing a grating with which a grating having a desired attenuate wavelength characteristic can be easily manufactured. The apparatus, which forms a grating in an optical fiber as an optical waveguide, includes a laser source, beam diameter adjusting means, a scanning mirror, mirror position adjusting means, a cylindrical lens, lens position adjusting means, a phase mask, mask position adjusting means, a stage, a fixing jig, and a synchronous controller. The synchronous controller controls an adjustment of a position of the scanning mirror performed by the mirror position adjusting means and an adjustment of a position of the phase mask performed by the mask position adjusting means in a manner in which they are associated with each other.

An optical fiber having at least two polymer coatings, the optical fiber comprising: an optical fiber comprising a glass optical core and a glass cladding; a first polymer coating comprising a silicone polymer covering the optical fiber; and a second polymer coating covering the first polymer coating is provided.