arXiv subjects

Erik Jung

Publications and source records attributed to Erik Jung.

6 recordsLinked to original sources

arXiv2026

Octave bandwidth 3D-Printed Couplers for Low-Loss Thin-Film Lithium Tantalate Circuits

Low-loss, broadband photonic integrated circuits (PICs) are critical enablers for optical communications, photonic computing, and quantum applications. Lithium tantalate on insulator (LTOI) is an emerging photonic platform offering a wide transparency window and strong Pockels effect, and thereby enabling efficient electro-optic modulation and high data rates. Here, we present the first implementation of efficient out-of-plane polymer coupling interfaces fabricated via 3D direct laser writing for both fully etched strip and partially etched rib LTOI waveguides, achieving ultra-low coupling losses of 0.9 dB (strip) and 1.25 dB (rib) per interface. Both coupler types exhibit a 3 dB optical bandwidth spanning more than an octave from 850 nm to 1740 nm and maintain stable operation under 1 W optical input power. Combined with on-chip waveguides exhibiting propagation losses below 0.1 dB/cm, these characteristics represent a key step toward unlocking the full potential of LTOI for high-speed optical signal processing with an unprecedented degree of parallelism. In addition, the octave-spanning bandwidth enables efficient interfacing of both the fundamental and second-harmonic signals, making the platform highly attractive for second harmonic generation based quantum squeezing applications.

physics.optics↗

arXiv2026

3D Photonic integration leveraging hybrid-confinement circuits

Three-dimensional (3D) photonic integration offers a pathway to overcome the fundamental scaling limitations of planar platforms by enabling enhanced routing flexibility for compact, low-loss, and highly interconnected photonic circuits. In this work, we fabricate 3D photonic circuits combining high-confinement air-clad waveguides for compact routing with low-confinement polymer-clad waveguides for robust single-mode operation within a monolithic platform. Efficient mode transition between polymer-clad and air-clad waveguides is demonstrated with a loss of 0.25 dB per interface. We also realize compact, Euler S- and U-shaped bends with minimal bending radii of 10 $μ$m and losses as low as 0.5 dB and 0.4 dB, respectively, along with compact adiabatic air-clad splitters exhibiting a splitting loss of 0.6~dB over a length of 52 $μ$m. Finally, full fabrication of a compact hybrid circuit is demonstrated, highlighting the feasibility and scalability of the approach. Our work represents a significant step in 3D photonic integration for applications including optical neural networks, photonic wire bonding and their potential for novel integrated photonic applications.

physics.optics↗

arXiv2025

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

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.

physics.optics↗

arXiv2024

Telecom wavelength quantum dots interfaced with silicon-nitride circuits via photonic wire bonding

Photonic integrated circuits find ubiquitous use in various technologies, from communication, to computing and sensing, and therefore play a crucial role in the quantum technology counterparts. Several systems are currently under investigation, each showing distinct advantages and drawbacks. For this reason, efforts are made to effectively combine different platforms in order to benefit from their respective strengths. In this work, 3D laser written photonic wire bonds are employed to interface triggered sources of quantum light, based on semiconductor quantum dots embedded into etched microlenses, with low-loss silicon-nitride photonics. Single photons at telecom wavelengths are generated by the In(Ga)As quantum dots which are then funneled into a silicon-nitride chip containing single-mode waveguides and beamsplitters. The second-order correlation function of g(2)(0) = 0.11+/-0.02, measured via the on-chip beamsplitter, clearly demonstrates the transfer of single photons into the silicon-nitride platform. The photonic wire bonds funnel on average 28.6+/-8.8% of the bare microlens emission (NA = 0.6) into the silicon-nitride-based photonic integrated circuit even at cryogenic temperatures. This opens the route for the effective future up-scaling of circuitry complexity based on the use of multiple different platforms.

physics.optics↗

arXiv2022

(3+1)D-printed adiabatic 1-to-N broadband couplers

We report single-mode 3D optical couplers leveraging adiabatic power transfer towards up to 4 output ports. We use the CMOS compatible additive (3+1)D \emph{flash}-TPP printing for fast and scalable fabrication. Coupling optical losses of such devices are reduced below $\sim$~0.06~dB by tailoring the coupling and waveguides geometry, and we demonstrate almost octave-spanning broadband functionality from 520~nm to 980~nm.

physics.optics↗

arXiv2015

A light-weight, multi-axis compliant tensegrity joint

In this paper, we present a light-weight, multi- axis compliant tenegrity joint that is biologically inspired by the human elbow. This tensegrity elbow actuates by shortening and lengthening cable in a method inspired by muscular actuation in a person. Unlike many series elastic actuators, this joint is structurally compliant not just along each axis of rotation, but along other axes as well. Compliant robotic joints are indispensable in unpredictable environments, including ones where the robot must interface with a person. The joint also addresses the need for functional redundancy and flexibility, traits which are required for many applications that investigate the use of biologically accurate robotic models.

cs.RO↗