Ultrabroadband tunable long-period fiber grating for stress sensing and optical filtering

Both constant-period and broadband chirped long-period gratings (LPGs) are generated in photonic crystal fibers (PCFs) by using a constant period V-grooved plate or solenoidal wiring device. The central wavelength and rejection bandwidth of LPGs can be tuned over a broad spectral range with adjustable transmission loss. In contrast to the conventional LPG sensors with longitudinal stretch or compression, the PCF-LPGs can be used for sensing the lateral pressure. They have potential applications for stress sensors and versatile optical filters.