Integrated Broadband Polarization Splitters Made by Ion-Exchange on Glass

In this letter, we present the design, fabrication, and characterization of a broadband polarization splitter working in the 1550-nm transmission window. The device is an asymmetric Y-junction realized by Ag
⁺
/Na
⁺
ion exchange on glass. The transverse electric (TE) output branch of the device filters out the residual transverse magnetic (TM) mode by radiation. Measurements show cross-talks better than (31.1±0.4) dB in TE and better than (32.7±0.4) dB in TM mode over a 70-nm bandwidth limited by the characterization source. Optimal values of, respectively, (33.6±0.4) dB and (37.2±0.4) dB were measured at 1540 nm. At this wavelength, the insertion losses are, respectively, (6.0±0.4) dB and (5.5±0.4) dB in TE and TM modes while the function losses are (0.65±0.12) dB and (0.35±0.12) dB, respectively.