We present the development and evaluation of metalenses fabricated with the two-photon polymerization-based 3D nanoprinting technology. In our design, we investigated a periodic lattice of multilevel nanopillars, based on the natural ellipsoidal shape of the 3D voxel in the fabrication process. By creating nanopillars with various heights, we can tune the effective refractive index of the metasurface in order to modulate the phase profile of an incoming light beam. We therefore push the fast and flexible two-photon polymerization technique to its limits in terms of dimensions in view of creating high performance metalenses. To demonstrate the optical performance of these metalenses, we also created their refractive and diffractive counterparts with the same fabrication technology to allow for a direct performance comparison. Moreover, we show that these metalenses can be fabricated on the tip of standard telecom single-mode optical fibers for the effective collimation of their output light beam.
We give an overview of our recent progress on the design and proof-of-concept demonstration of interfacing components for short-distance optical interconnects with a particular emphasis on their fabrication through two-photon polymerization-based laser direct writing. We show mode field conversion tapers printed on single-mode optical fibers for easy and efficient interfacing to various photonic integrated circuits, circular and square planar waveguide structures with V-groove inspired alignment structures for easy coupling to fibers, microlenses and fan-out diffractive optical elements.
We present the design, fabrication, and characterization cycle of a diffractive optical element based layout, used for 1-to-7 power splitting of a Gaussian beam emitted by a single-mode fiber. First, a modified version of our earlier demonstrated mode conversion up-taper structure is designed, fabricated, and characterized, increasing the mode-field diameter of the fundamental mode by a factor of 2. Then, a newly designed diffractive optical element is optimized to convert the expanded field distribution to a seven Gaussian-spot hexagonal array with 45 μm spacing, at an optimal propagation distance of only 61 μm, achieving splitting in a non-paraxial diffraction regime. The two components are combined into a monolithic design encompassing both adiabatic field expansion and efficient phase modulation in a single, highly miniaturized component. The power splitter is fabricated directly on the cleaved facet of a single-mode fiber, in a single step, using direct laser writing based on twophoton polymerization. The small spatial extent of the power splitter allows for a highly compact, integrated solution for wide-angle, fan-out power splitting of a Gaussian beam in single-mode interconnect and sensing applications.
We give an overview of our recent progress on interfacing components for short-reach optical interconnects fabricated through two-photon polymerization-based laser direct writing. We show mode field conversion tapers printed on single-mode optical fibers for easy and efficient interfacing to various photonic integrated circuits, circular and square planar waveguide structures with V-groove inspired alignment structures for easy coupling to fibers and fan-out diffractive optical elements. For all these components, we present the process flow from optical design and simulation over laser direct writing fabrication and metrology to proof-of-concept demonstration.
We present our latest results on the design and fabrication of mode-field conversion tapers for low-loss optical interconnects. These structures are fabricated by means of two-photon polymerization-based 3D nanoprinting. We experimentally demonstrate that our 3D nanoprinted downtapers outperform conventional lensed fibers for low-loss edge coupling of single-mode fibers with SOI, Si3N4 and InP-based photonic integrated circuits. They are also more robust as they allow butt coupling rather than free-space coupling. Non-linear taper profiles allow shortening the length of the downtapers while keeping their performance. We also demonstrate 3D nanoprinted uptapers that allow for relaxation of the lateral misalignment tolerances.
Photonic Integrated Circuits have made it possible to decrease the footprint of traditionally bulky optical systems and they create opportunities for various new and fascinating applications. One of the limiting factors for the widespread adaption of PICs is their connection to the outside world. As the mode field diameter of optical modes in waveguides tends to be an order of magnitude smaller than in their fiber counterparts, creating an efficient, robust and alignmenttolerant fiber-to-chip interface remains a challenge. In this work, we investigate the optimization of the fiber-side of the optical interface, whereas the chip itself remains untouched and makes use of spot-size convertors. Optical fiber tips can be functionalized using two-photon polymerization-based 3D nanoprinting technology, which offers full 3D design freedom and sub-micrometer resolution. We present a down-taper design strategy to match the mode-field diameter of single-mode optical fibers to the modefield diameter of waveguides with spot-size converters on PICs. The 3D printed down-tapers are characterized towards their geometry and mode shape, and we experimentally demonstrate their use for coupling towards a Silicon-On-Insulator chip with spot-size convertors. Furthermore, the performance of these down-tapered fibers is compared to conventional lensed fibers in terms of optical coupling efficiency.
Optical fiber technology is the driving force behind the ever-increasing data transport and internet usage in today’s connected society. The tight alignment tolerance required when connecting single-mode telecom fibers become even more tight when multiple fiber connectors are being used in the optical link. To alleviate this, we expand the mode field of the fiber and use 3D nanoprinting to print taper structures that can relax alignment tolerances in physical contact expanded beam connectors. We present the design and fabrication of a linear taper which expands the fundamental mode of a single-mode telecom fiber adiabatically with a factor of 3. The taper itself was fabricated on top of a cleaved fiber facet with the two-photon polymerization-based 3D nanoprinting technique, which allows fabrication of high aspect-ratio structures with submicrometer resolution. A proof-of-concept demonstrator was built to measure the obtained misalignment tolerance relaxation. Experimental results for lateral misalignment show excellent agreement with simulated values, but the beam expansion with an air-cladding taper also induces an excess loss of about 0.22 dB compared to a standard physical contact connection without beam expansion. This shows the compromise that has to be made between insertion loss and misalignment tolerance relaxation. The use of additive manufacturing techniques in fiber beam expansion applications makes it possible to fabricate taper structures with full 3D design freedom.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.