Ultra-broadband polarization beam splitter and rotator based on 3D-printed waveguides

TL;DR

This paper presents a novel 3D-printed ultra-broadband polarization beam splitter and rotator that operate efficiently over a wide wavelength range, enabling advanced polarization control in integrated photonic systems.

Contribution

It introduces a monolithic 3D-printed structure combining polarization beam splitting and rotation, extending the functional capabilities of laser-printed photonic components.

Findings

Achieved polarization extinction ratios beyond 11 dB over 350 nm bandwidth.

Successfully received 640 Gbit/s dual-polarization 16QAM signal without OSNR penalty.

Demonstrated integration of polarization control devices directly on optical device facets.

Abstract

Multi-photon lithography has emerged as a powerful tool for photonic integration, allowing to complement planar photonic circuits by 3D-printed freeform structures such as waveguides or micro-optical elements. These structures can be fabricated with high precision on the facets of optical devices and lend themselves to highly efficient package-level chip-chip-connections in photonic assemblies. However, plain light transport and efficient coupling is far from exploiting the full geometrical design freedom that is offered by 3D laser lithography. Here, we extend the functionality of 3D-printed optical structures to manipulation of optical polarization states. We demonstrate compact ultra-broadband polarization beam splitters (PBS) that can be combined with polarization rotators (PR) and mode-field adapters into a monolithic 3D-printed structure, fabricated directly on the facets of optical devices. In a proof-of-concept experiment, we demonstrate measured polarization extinction ratios beyond 11 dB over a bandwidth of 350 nm at near-infrared (NIR) telecommunication wavelengths around 1550 nm. We demonstrate the viability of the device by receiving a 640 Gbit/s dual-polarization data signal using 16-state quadrature amplitude modulation (16QAM), without any measurable optical-signal-to-noise-ratio (OSNR) penalty compared to a commercial PBS.