Six-mode scrambler based on cascaded side-wall grating waveguides

Abstract

Abstract A six-mode scrambler based on cascaded side-wall long-period-grating waveguides on a silica planar lightwave circuit (PLC) platform is proposed for mode-division-multiplexing (MDM) transmission. The device can be fabricated with only one-step etching since it does not use a surface grating. A mode-dependent loss (MDL) of the system is estimated and the MDL can be reduced with a multiple scrambling operation. Two gratings proposed here and a fiber-pigtailed module containing these gratings are fabricated and the expected proof-of-concept mode scrambling operation is confirmed. It is found that the connection between few-mode fiber (FMF) and PLC chip seems to be the dominant loss of the module. Considering these losses, the measured results are in good agreement with the calculated results.