Point-by-point inscribed sapphire parallel fiber Bragg gratings in a fully multimode system for multiplexed high-temperature sensing
Guannan Shi, Randy Shurtz, Gary Pickrell, Anbo Wang, Yizheng Zhu
Abstract
We study the point-by-point inscription of sapphire parallel fiber Bragg gratings (sapphire pFBGs) in a fully multimode system. A parallel FBG is shown to be critical in enabling detectable and reliable high-order grating signals. The impacts of modal volume, spatial coherence, and grating location on reflectivity are examined. Three cascaded seventh-order pFBGs are fabricated in one sapphire fiber for wavelength multiplexed temperature sensing. Using a low-cost, fully multimode 850-nm interrogator, reliable measurement up to 1500°C is demonstrated.
Topics & Concepts
Fiber Bragg gratingOpticsMaterials scienceMulti-mode optical fiberPHOSFOSSapphireMultiplexingLong-period fiber gratingFiber optic sensorGratingOptoelectronicsOptical fiberWavelengthPlastic optical fiberLaserPhysicsComputer scienceTelecommunicationsAdvanced Fiber Optic SensorsPhotonic and Optical DevicesPhotonic Crystal and Fiber Optics