Light Modulation Based on Fiber Cladding Mode Coupling Between Concatenated Long-Period Gratings

In-fiber efficient light modulation using two concatenated long-period gratings (TCLPG), written in single-mode fiber, is reported. The device is compressed in the middle of both gratings against a corrugated surface, with a piezoelectric, producing a transfer of energy between cladding modes which results in modulated light transmission. The TCLPG operates at 1542 nm, with a bandwidth of 29 nm and an insertion loss of 0.3 dB. The modulation depth is 20 dB and the rise time is 7.5 ms at a repetition rate of kilohertz.