TE/TM mode electro-optic conversion based on a titanium diffusion lithium niobate waveguide with a polarization-maintained fiber structure.

For the development of photonic integrated circuits and lithium niobate ( , LN) optical waveguide technology, the implementation and application of polarization devices based on LN are also becoming more widespread, where titanium (Ti)-diffused LN waveguides form the basis of many important electro-optic (EO) integrated optical devices. Moreover, utilizing polarization conversion has the potential to enhance both the effectiveness and capacity of optical transmission. Thus, we have presented an EO polarization mode converter packaging with PANDA polarization-maintaining optical fibers (PMFs) in the broadband wavelength range (1440-1620 nm) to obtain the multiwavelength modulation, featuring the wavelength tunability. Additionally, the fabricated device is able to achieve transverse electric (TE) to transverse magnetic (TM) mode conversion efficiently with the applied voltage of  ±, which provides high conversion efficiency. Importantly, our device also features a high-frequency response of about 600 MHz with overall insertion loss below 5 dB. The rapid development of LN-based polarization devices holds great promise for chip-integrated systems in the field of polarization telecommunication.