Ultra-Broadband plug-and-play photonic circuit packaging with sub-dB loss

TL;DR

This paper presents a novel, low-loss, broadband plug-and-play packaging solution for photonic integrated circuits, significantly improving fiber-to-chip coupling efficiency and scalability for advanced photonic computing applications.

Contribution

Introduction of a scalable, low-loss, broadband fiber-to-PIC packaging method using additively fabricated 3D couplers and multi-fiber connectors, enhancing photonic circuit integration.

Findings

Peak transmission of -0.41 dB for 3D couplers

Losses below 0.55 dB across 1500-1600 nm range

Record passive out-of-plane packaging loss of 0.78 dB

Abstract

Photonic Integrated Circuits (PICs) offer transformative potential for computing systems, enabling high-bandwidth neuromorphic processors and facilitating low decoherence quantum computing on a chip scale platform. However, the development of robust and scalable optical packaging solutions remains a major challenge. Efficient fiber-to-chip coupling is essential for minimizing loss and enabling high optical bandwidth, key requirements for photonic computing. Here, we introduce a novel plug-and-play solution for fiber-to-PIC connections using female multi-fiber termination push-on cables and additively fabricate the alignment counterpart on the circuit via two-photon polymerization. We develop 3D out-of-plane couplers, offering a peak transmission of -0.41 dB and broadband performance with losses below 0.55 dB across the 1500-1600 nm range. Integration of the couplers with the plug-and-play solution adds in average only 0.37+-0.12 dB of loss, setting a record in passive out-of-plane packaging solution with losses of 0.78 dB, as well as -0.5 dB bandwidth greater than 100 nm. We characterize the reproducibility of this out-of-plane packaging solution in terms of losses, as well as bandwidth by interfacing a 17-port photonic circuit for incoherent photonic computing. The high bandwidth of the packaging is crucial to couple the full 100 nm bandwidth spectrum of a superluminescent light emitting diode, which consequently enables low noise computing at 17.6 GBaud. Our concept enables multiport, passive and reconfigurable photonic integrated circuit packaging providing reliability and versatility driving photonic packaging towards the scalability and robustness of electric chip packaging.