Reconfigurable broadband mode (de)multiplexer based on an integrated thermally induced long-period grating and asymmetric Y-junction.

We propose a reconfigurable broadband mode (de)multiplexer based on a thermally induced long-period grating integrated with an asymmetric Y-junction. Either of the two spatial modes of a two-mode waveguide launched into the grating end of the device can be switched into either of the two output ports of the Y-junction by controlling the electric power applied to the electrode heater that induces the grating. Our typical device fabricated with polymer material that has a length of ∼14  mm shows a mode selectivity higher than 12 dB over the C+L band at a switching power of 198 mW. The device could find applications in reconfigurable mode-division-multiplexing systems.