Ultra-Broadband Mode Filter Based on Phase-Shifted Long-Period Grating

Authors：Huang, Quandong; Wang, Wen; Jin, Wei; Chiang, Kin Seng^*

Source：IEEE Photonics Technology Letters, 2019, 31(13): 1052-1055.

DOI：10.1109/LPT.2019.2917388

• Integrated optics devices
• gratings
• optical polymer
• optical waveguide components

We propose an ultra-broadband mode filter based on the structure of a phase-shifted long-period grating formed along a few-mode waveguide terminated with two linear tapers. To demonstrate the operation principle, we design a mode filter to reject the fundamental mode of a three-mode waveguide that supports the E-11, E-21, and E-12 modes. Our typical experimental device fabricated with polymer material, which has a length of 26 mm, provides polarization-insensitive 10-dB rejection of the E11 mode against the E-21 and E-12 modes with bandwidths of similar to 190 nm (1440-1630 nm) and similar to 140 nm (1450-1590 nm), respectively. The proposed mode filter could serve as a general platform for the development of mode filters and mode-dependent-loss compensators for mode-division-multiplexing applications.

• Institution
  香港城市大学; 电子科技大学