Polymer waveguide tunable transceiver for photonic front-end in the 5G wireless network

A photonic front-end in the 5 G wireless network based on wavelength-division multiplexing optical communication requires low-cost tunable transceivers. By exploiting polymer waveguide Bragg-grating technology, we propose a tunable transceiver consisting of an external cavity tunable laser and a tilted grating tunable filter.In particular, a double-reflection tunable filter provides narrower reflection bandwidth and suppresses undesired mode coupling, improving the side-mode suppression ratio(SMSR) and reducing adjacent-channel crosstalk. By introducing perfluorinated polymers with low birefringence, polarization independence, which is a prerequisite for wavelength filter elements, is secured, and 20 d B bandwidth of 0.69 nm, wavelength tunability over 40 nm,and SMSR of 42 d B are achieved.