Broadband mode scramblers for few-mode fibers based on 3D printed mechanically induced long-period fiber gratings

We present simple, low loss and broadband mode scramblers for mode division multiplexed (MDM) transmission based on few-mode fibers. By simply shortening the length of the long-period fiber grating (LPFG), the optical bandwidth is significantly enhanced and >260 nm bandwidth is predicted in our simulations with a grating length of 0.613 cm. In an experimental demonstration we fabricate a mechanically induced LPFGs using a commercially available 3-dimentional (3D) printing technique and wideband operation is confirmed over the C band with a low loss (0.2 dB) and low mode dependent loss (0.1 dB)