Ultra-broadband polymer E00/E10 mode converter

An ultra-broadband and compact E00/E10 polymer mode converter composed of a symmetric Y-branch 3-dB coupler, a phase shifter and a 2 × 1 multimode interferometer is theoretically designed and experimentally demonstrated. Within the wavelength range from 1470 to 1690 nm, calculated results show that the mode crosstalk is less than –22.6 dB and insertion loss is less than 5 dB. Moreover, the calculated mode crosstalk and insertion loss are less than –29.8 dB and 3.6 dB in C-band (1530–1565 nm), respectively. To verify the proposed design, the waveguide mode converter was fabricated and polymer materials EPOcore and EPOclad are adopted as the core and cladding materials, respectively. The measured mode crosstalk varies from –26.2 dB to –15.4 dB and the insertion loss varies from 4.8 dB to 9.2 dB in the wavelength range from 1500 to 1630 nm. Benefit from the advantages of broadband and compactness, this proposed mode converter has potentials in future complex hybrid multiplexing applications.