Modern microchip-scale transceivers are capable of transmitting data at rates of the order of several terabits per second. In this regard, there is an urgent need to improve the interfaces connecting ...the chips and extend the bandpass of the interconnections. We use an approach combining silicon nitride nanophotonic circuits with 3D polymer waveguides fabricated by direct laser writing, which can be used as photonic interconnections or photonic wire bonds (PWB). These structures are designed, simulated, fabricated, and optimized for better light transmission at the telecommunication wavelength. An important part of this work is the study of the telecom signal transmission in a 3D polymer waveguide connecting two silicon nitride facing tapers. Two cases are considered: the tapers are one opposite the other or misaligned. Initially, the PWB shape was chosen to be Gaussian and then optimized: the top was circle-shaped and with the lower part still being Gaussian. Transmission losses were measured for both types of waveguides with different shapes. The idea of an optical multi-level crossing for photonic integrated circuits is also suggested as a solution to the problem of interconnections within a single chip.
Abstract
We present a way for micro-lens and micro-lens array fabrication on the fiber facet by direct laser writing (DLW) method. The proposed setup for DLW printing on the fiber facet can protect ...objective lens and makes it possible to safely using a wide range of resists. Microlens fabricated on the single-mode optical fiber facet is demonstrated. Based on lens-on-fiber system we proposed concept of the micro-lenses on baseplate array printed on the multi-core fiber, where each lens is rigidly aligned with the core. One of the possible micro-lenses on the baseplate array is presented and its optical properties such as focal spot size and resolution are investigated. The possible application of the proposed micro-lens array is complex optical elements, such as micro-objectives with optimized optical design. Moreover, suggested freeform lens array can find application in high-accuracy wavefront sensing.
The existing refractive optical elements of silicon and beryllium for X-ray optics have some limitations that do not allow them to be used as lenses for high-resolution wide-field X-ray microscopy. ...Therefore, search for new materials and production methods is of major current importance. The additive technology—a two-photon laser lithography method for producing refractive elements of the X-ray range—is considered. It enables making three-dimensional polymeric structures of an arbitrary shape with a resolution of <100 nm, including complex-shaped optical elements. The technology has been used to manufacture refractive microlenses for the X-ray range. The microlenses have been subjected to morphological investigations, in particular for optimizing lithography parameters, such as the printing speed and laser radiation power. On the basis of the results, correction algorithms are proposed for minimizing the morphology distortion of the thus produced microlenses.
Two-photon laser polymerization (TPP) is a state-of-the-art technology that allows for the submicron-resolution printing of freeform 3D objects to be harnessed in various applications, including ...physics, biology, medicine, and materials science. The TPP is based on using photosensitive polymeric materials that impose restrictions on the minimum feature size and limit the functionality of printed structures within the capabilities of polymers. One of the promising yet insufficiently studied methods for overcoming these limitations is pyrolysis–high-temperature annealing of polymer objects in an inert atmosphere. It may allow both to decrease the size of the objects and modify their chemical composition. Here, we compare the effect of pyrolysis on solid objects being tens of micrometers in size printed by TPP from three commercially available photoresists: IP-Dip, OrmoComp, and SZ2080. For the annealing temperatures of 450°C and 690°C in an argon atmosphere, we assessed the changes in size, chemical composition, and adhesion to the silicon wafer substrate. Our data may be promising for developing pyrolysis as a standard post-processing method for structures created via TPP technology.
The importance of creating hybrid photonic integrated circuits with complex architecture is due to the need for high-performance systems for transmitting and processing large volumes of data. A study ...is performed of three-dimensional photonic waveguide structures created by direct (3 + 1)D laser printing, with the aim of adding such structures to photonic integrated circuits.
Aspherical microlenses and microlens arrays allow increasing efficiency of various optical devices. However, it is technologically challenging to produce these items. The problem arises from ...impossibility of making microlenses with an arbitrary profile in a characteristic size region of several tens of micrometers using traditional technologies like single-point diamond milling and thermal reflow. In this work, a precisely aligned combination of an aspherical microlens and a microlens array produced by the two-photon polymerization direct laser writing (2PP-DLW) is presented. This structure is designed and optimized using computer simulation methods. A unique photosensitive composition based on the methacrylate dye (derivative of benzylidene cyclopentanone) is used to produce the structures. A specific feature of the chosen composition is dependence of its mechanical and optical properties on the femtosecond radiation dose which could widely vary during the fabrication. The produced structures are investigated using laser scanning confocal microscopy, which allows reconstruction of the 3D image of the structures and detailed analysis of their morphological properties. The aspherical microlens aligned with the microlens array has a wide range of applications in production of complicated optical devices, optimized microobjective lenses for high-precision wave front sensing, and refractive X-ray lenses.
The report proposes a discussion of the effective combination of two current trends: the additive 3D printing method and the development of multicomponent photonic schemes, as well as the development ...of the foundations of additive scalable and flexible optical technology for creating interconnects and optical structures, which can solve problems such as the creation of interchip optical compounds, various optical and quantum-optical systems on a chip (resonators, modulators, photon detectors, single-photon radiation sources, etc.).
Microoptics opens up new opportunities for effective transformation of the radiation wavefront at the needed position using optical fiber. Here we discuss the use of a micro-connector kit for ...relative positioning of an optical fiber with nanometer accuracy. A single technological process of the DLW-lithography (Direct Laser Writing) to create all optical elements of the kit: optical fiber micro-connector and micro-lens, is used to solve the key problem of the precise alignment of optical elements. Micro-lens assisted single-mode fiber with high light coupling efficiency is demonstrated. Further improvement of this light coupling kit is based on aligned micro-lens array combined with multi-core optical fiber (MCF), where each micro-lens is located directly opposite to its own core. Nanometer accuracy of micro-lenses location could be achieved due to proposed and demonstrated printing process. Such kit significantly improves performance of optical instruments for spatially resolved spectroscopy. One of the possible important applications of MCF-based light coupling kit with individual lens design for each core is a real-time 3D-imaging. Moreover, parallel multi-beam laser processing with such kit is of great importance.
The possibility of using a series of methacrylate-containing
N
,
N
-diethyl-4-(phenyldiazenyl)anilines with various
para
-substituents (–H, –Br, –NO
2
) relative to the azo group as photoinitiators ...of radical polymerization is considered. The electrochemical and photoluminescent properties of these compounds have been studied. In the presence of azo dyes, two-photon photopolymerization of pentaerythritol triacrylate was carried out using focused 780-nm radiation from a femtosecond laser. Structures with minimal dimensions of linear elements of 94 ± 5 nm were obtained by means of the DLW nanolithography technique, and 3D microstructures of complex architecture were fabricated.
PDF
