The new 3D printed photonic lamp opens up possibilities for spatial multiplexing

Optical waves propagating through air or multimode fibers can be shaped or decomposed using orthogonal spatial modes, with far-reaching applications in imaging, communications, and directed energy. However, the systems that perform these wave manipulations are bulky and large, limiting their use to high-end applications.

The development of a free-standing photonic lamp spatial mode (de-)multiplexer using 3D nanoprinting, as revealed by a recent study, marks a significant advance in photonic technology. This spatial multiplexer, characterized by its compactness, minimal footprint and the ability to directly print and stick on photonic circuits, optical fibers and optoelectronic elements such as lasers and photodetectors, opens up new possibilities in system integration and technology adoption in the future. – capacity communication systems and demanding recording modalities.

The work is published in the journal Light: Science and Application.

The study of Ph.D. candidate student Yoav Dana, under the supervision of Professor Dan Marom and his team at the Institute of Applied Physics of the Hebrew University of Jerusalem, in partnership with scientists from Nokia Bell Labs, resulted in the development and demonstration of a free-standing microscale photonic lamp spatial mode (de-)multiplexer. The tiny photonic lamp was produced using a 3D nanoprinting technique using direct laser writing, applied directly to the tip of an optical fiber.

Photonic lamp devices convert optical waves containing a superposition of modes or distorted wavefronts and vice versa into a series of separate single-mode optical signals. The technology stands out as a promising candidate for enabling spatial multiplexing (SDM) in future high-capacity optical communication networks, as well as in image processing and other applications that require spatial manipulation of optical waves.

By leveraging the capabilities of 3D nano-printing and using high-contrast-index waveguides, researchers have developed a compact and versatile device that can be printed on almost any solid platform with fine precision and high fidelity, enabling its seamless integration into a variety of technological contexts. The ~100 micrometer size device is in stark contrast to traditional photonic lamps based on weakly guiding waveguides that are millimeter–centimeter long, which makes integration with microscale photonic systems very challenging.

«The development of this freestanding photon lamp spatial mode (de-)multiplexer represents a significant advance in our ability to enable and adopt spatial multiplexing for a variety of optical systems and applications,» said Professor Dan Marom. «This discovery makes space multiplexing technology more accessible and amenable to integration, opening up new possibilities for optical communication and imaging applications, to name a few.»

The researchers presented a device design using genetic algorithms, fiber-top fabrication, and characterization of a 375-µm-long, six-mode mixing photonic lamp that can convert six single-mode inputs into a single six-mode waveguide. Despite its compact size, the device exhibits low insertion loss (-2.6 dB), low wavelength sensitivity, and low polarization- and mode-dependent losses (-0.2 dB and -4.4 dB, respectively).