Ultrasensitive long-period fiber gratings for broadband modulators and sensors.
We demonstrate long-period fiber gratings whose attenuation can be changed by 25 dB over a 48-nm spectral band, with ambient-index changes of only 2.7 x 10(-4). To achieve this, the fiber waveguide is engineered to induce coupling between the core and a highly ambient-sensitive cladding mode with identical group velocities. The device schematic allows arbitrarily high index sensitivities to be achieved, which makes it an attractive platform for realizing sensors and modulators that respond to small index changes.
Wang
Zhiyong
Z
Department of Electrical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA. sidr@ofsoptics.com
Ramachandran
Siddharth
S