March 17, 2018

— News — News — News — News — News — News —-

Dear customers, partners and friends,

time is flying, and the first quarter of 2018 started very exciting with Multiphoton Optics’ nomination for the PIC Award 2018 in the category “Advanced Photonic Integration” – if you like what you see and know about us we appreciate your vote. To demonstrate what we have done so far in the field of photonic integration and High Precision 3D Printing, some of the highlights in a more historical overview of the related works are summarized at the end of this newsletter. These went public through talks and publications in the last 18 years. The historical overview comprises the works carried out during our CEO’s time at Fraunhofer, together with partners, students, and agencies who were involved in these works and whose funding, cooperation, and passion are gratefully acknowledged by our CEO.

Back to this year. Beginning 2018, we attended Photonics West Conference and Exhibition in San Francisco and Nanotech Exhibition in Tokyo, PIC Conference and Exhibition is coming up in April, and we use these opportunities all over the globe to demonstrate our High Precision 3D Printer Platform’s LithoProf3D® industrial throughput, scalability, and cost-down processes with a large variety of different materials and precision on demand. Aside of this, our equipment can be uniquely integrated into standard process workflows such as semiconductor processes on waferscale, among others.

The Multiphoton Optics’ Team – “The MPO Team” – is eager to take the heat of challenging projects to support our customer’s product developments. We have produced some video clips and selected some of the highlights in High Precision 3D Printing we have created to give you a slight insight in our capabilities, apart from of the cool stuff we are unfortunately not allowed to show.

Enjoy the read, yours sincerely

LithoProf3D® – First 3D Printing Equipment capable of Wafer-Scale Production. – High Throughput and Scalable 3D Prototyping and Production with Highest Precision. – Large variety of Materials. – Vision2Align System. – Scalable Formats and Processes. – Automation. – Upscaling. – Lean processes. – Integration in Standard Workflows. – Green Technology.

PIC Award 2018 Nominee

Multiphoton Optics raises the bar in High Throughput Fabrication with its High Precision 3D Printer LithoProf3D® for Photonics Packaging. The team is excited to be nominated in the Category Advances in Photonics Integration. This category recognizes innovative approaches to new and commercially important PIC technology platforms, PIC packaging, PIC design that results in more features into a chip and raising the bar to the next level. Our team appreciates all support via your votes to enhance its visibility, necessary to stand out of these impressive nominees – among which are large companies such as IBM, Intel, Cisco, Juniper, or even large consortia from academia and industry, and – Multiphoton Optics. Please spread the news into your networks and support us with your vote via Voting is open through March 23, 2018.

First waferscale high precision 3D printing worldwide

The First Industrial Scale High Precision 3D Print on Waferscale Made in Germany was shown at Photonics West. A 4” glass wafer from Plan Optik AG was used to print various structures in a continuous writing mode using Multiphoton Optics’ High Precision 3D Printer LithoProf3D®. The printer works on any substrate and is not limited to special formats and shapes. Follow our continuously growing scaling activities. Multiphoton Optics – Always a step ahead.


Bavarian Ministry of Economic Affairs and Media, Energy and Technology, grant: TOU-1512-004.

Improving the far-field

IR lasers are widely used in sensor products. In a cooperation of nanoplus GmbH and Multiphoton Optics GmbH presented at this years’ Photonics West, we have raised the next level in low-cost packaging. With cylindrical microlenses directly printed onto laser die facets, the lasers’ far fields are improved significantly without the necessity of beam shaping optics in the final sensor system. The fabrication only involves three process steps: dispensing, additive manufacturing of the lens, development step. Aside of the direct output of a spherical far field, the divergence angles of slow and fast axes were also improved by the printed microlenses. The lasers are stable for already more than 500 h with ongoing tests, showing very good stability.

About nanoplus GmbH

nanoplus Nanosystems and Technologies GmbH, Germany, is an ISO 9001:2008 and ISO 14001:2004 certified supplier of semiconductor devices and one of the leading manufacturers of lasers for gas sensing applications. For more information, please visit

Direct printing of microoptics on LED chips

LEDs are the next generations’ light sources. Their advantages are manifold and include lower energy consumption in use, they usually have a longer lifetime, and they are more robust. LEDs have a smaller footprint and can be assembled in many different ways, and a large variety of products were developed, ranging from automotive and aviation lighting via lighting in general (households, traffic lights, cameras, medical devices, etc.), and data communication. Despite the positive impact LEDs provide, there are still challenges which remain. One prominent challenge is thermal management which, for example, influences the color consistency of the emitted light. Another challenge is the homogeneous distribution of light, particularly if automotive or general lighting products are considered. To shape the radiation pattern of an LED, integrated optical components might be used. A very simple and reliable approach avoiding any complex processing was presented on this years’ Photonics West, which is the direct integration of specially designed microoptics on the LED chips. Demonstration was done using bare LED chips of Epigap Optronic GmbH, Berlin, Germany. The fabrication only involves three process steps: dispensing, additive manufacturing of the lens, development step. The investigations are still ongoing, involving optical and reliability characterization.

About EPIGAP Optronic GmbH

EPIGAP Optronic GmbH was formed in 2011 as new company after integration of EPIGAP GmbH into a group company. The company stands for profound know how in semiconductor technology for production of LED and photodiode chips, being employed in various branches of industry, medical technology, industrial sensors, special lighting, and safety technology.

“Skalierbarkeit des hochpräzisen 3D-Drucks“, published in “Mikroproduktion“, Issue 5/17 (Sept. 2017),


Step and repeat via replication of master structures provides a basis for increasing throughput and decreasing fabrication costs at the same time. With our key technology, arbitrarily shaped 3D master structures which include microlens arrays or arbitrarily arranged shapes in arrays are fabricated. These arrays can then be used as-is or to manufacture a replication tool to be used for mass fabrication. High Precision 3D Printing Platform LithoProf3D® – your gateway to fully digitized manufacturing from prototyping to volume production.


Bavarian Ministry of Economic Affairs and Media, Energy and Technology, grant: TOU-1512-004.

Fabrication of Centimeter-Scale Lens Arrays

Fabrication of 1 cm2 microlens arrays consisting of 6,400 lenses closely packed on substrates is already water under the bridge for Multiphoton Optics’ High Precision 3D Printer LithoProf3D®. We used this in the beginning of last year as a benchmark, where we demonstrated a worldwide unrivaled enhancement of the fabrication throughput. We have continued to scale up the fabrication formats, and we are ready to take the next steps for a further upscale in productivity. Aside of the extraordinary good machine performance, the increase in productivity is achieved by implementing the company’s team know how on materials, processes, and light-matter interaction of more than 30 years into the fabrication strategies. These are continuously implemented into our software producing the codes to drive the machine and the exposure strategies. As an example, we have produced a 4 cm2 microlens array consisting of 20,000 individual lenses of a diameter of 100 µm, a height of 20 µm, and a pitch of 125 µm, resulting in a filling factor of app. 50 %.

Part of this work was published in Laser & Photonics, January 2018, pp. 80 – 85.

High Aspect ratio structures fabricated in an Infinite Field of View (IFoV) Mode

Our customer’s requirements challenge us continuously. New product ideas often need new ways of handling processes, underlying physics and chemistry which we have implemented into the fabrication processes as part of the High Precision 3D Printing Platform LithoProf3D® to demonstrate sophisticated structures and product ideas. Particularly our IFoV fabrication mode allows the customers to create structures far beyond the FoV of the implemented objectives. To demonstrate this, we have created high aspect ratio free standing walls which were manufactured in the IFoV mode using a 100x Zeiss Plan Achromat objective with an NA of 1.4 (effective FoV in the LithoProf3D® setup: app. 140 µm). The walls have a thickness of 5 µm, a height of 80 µm, and a length of 500 µm. The aspect ratio in the chosen demonstration setup is 16:1, and the limits are not tackled yet.

Published in: “Skalierbarkeit des hochpräzisen 3D-Drucks“, published in “Mikroproduktion“, Issue 5/17 (Sept. 2017),

Monolithically fabricated lens stacks

The capability of Multiphoton Optics’ High Precision 3D Printing Platform LithoProf3D® for industrial scale works was demonstrated by the fabrication of monolithically integrated microlens stacks. These consist of five different individual freeform lens structures, i.e. ten differently shaped surfaces in total. To get a better insight into the structures, a piece of the stack was cut as for a pie. The diameters of the stacks are 100, 200, 300, and 400 µm, fabricated with Multiphoton Optics’ LithoProf3D® as fast as in 5 minutes (diameter 100 µm) to 100 minutes (diameter 400 µm). The medium sized structures were fabricated in 20 and 50 minutes, respectively. No supporting structures are necessary in the fabrication mode, and “mounting” of the individual optical elements is intrinsically provided by Multiphoton Optics’ technology. It is just three steps: dispensing of the material, fabrication of lens stack, development stepThis significantly reduces cost and also significantly enhances the yield in production.

EU Project PHENOmenon started

In PHENOmenon, 12 partners from five different countries started to develop and validate an integral manufacturing approach (material, process, and technology) for large area direct laser writing of 2- and 3D optical structures, targeting high speed production of optical surfaces with subwavelength resolution. Multiphoton Optics as integral part of this project is committed to significantly support these developments with its know-how and cooperation among the partners, creating new jobs, economic growth, and support to create a knowledge-based society through education, training, and exploitation through innovation. Developments in photochemistry and laser beam shaping will allow producing structures at different scales. An unedited productivity in freeform fabrication of 3D structures will trigger the manufacturing of new and powerful optostructures with applications in lighting, displays, sensing, etc. via massive parallelization. The novelty focuses on the combination of ultrasensitive nonlinear photocurable materials, and the laser projection of up to 106 simultaneous laser spots. The photochemistry relies on new types of ultrasensitive photoinitiators and groundbreaking nonlinear sensitized resins. The developments in beam shaping are based in modulation with SLMs and hybrid diffractive optics for massive 3D parallelization by imaging and holographic projection.

Donandi (Thingiverse) is gratefully acknowledged for providing the 3D model of Godzilla.

School Training Program – The Smallest Godzilla of the World

In the secret printing lab of Multiphoton Optics, scientists created a tiny monster: the original GODZILLA. It is based on the Japanese movie from 1954, in which the monster Godzilla, slumbering for millions of years underwater is awakened by nuclear weapon tests and destroys everything in its way by its nuclear fire breath. The about 160 µm ‘tall’ Godzilla, even in this tiny and weak form, develops enormous powers destroying an artificially built city. Skyscrapers and pagodas cannot withstand its tremendous nuclear breath and tumble, get twisted, or collapse. This project was done in cooperation with the young 9th grade scientist Hannah Koeth as a school training program. She presumably will become a dedicated Godzilla researcher in the near future.

Historical Background in Photonics Integration

Top: Description of the microcollimator for optical design (h = 260 µm, T = 690 µm, D = 250 µm) and model for fabrication in Mutliphoton Optics’ software. Bottom: Microcollimator on an ST chip (courtesy of Inphotec TeCIP and ST).


Inphotec TeCIP, ST, Multiphoton Optics


R. Houbertz, G. Preve, S. Steenhusen, M.A. Shaw, Presentation at SPIE Photonics West (2016).

Keep It Simple – Microcollimators on Grating Couplers

Supercomputing is reaching out to ExaFLOP processing efficiencies, creating fundamental challenges for the way that computing systems are designed and built. The governing topic is the reduction of power used for operating the computer system, and eliminating the excess heat generated from the system. Current thinking sees optical interconnects on most interconnect levels to be a feasible solution to many of the challenges, although there are still limitations to the technical solutions, in particular with respect to manufacturability in high volume. In a joint work of Inphotec TeCIP, ST, and Multiphoton Optics, we introduced a new type of grating coupler at Photonics West 2016. This element allows to significantly decrease the overall package size in vertical direction. Apart from the higher degree of miniaturization, fiber positioning tolerances are more relaxed compared to present grating couplers. Fabrication times could be improved from 27 h down to as low as app. 15 min per piece if serially produced which can be further reduced using parallel fabrication modes. The coupler was directly additively fabricated on the chip w/o any additional assembly process, with only three process steps: dispensing of the material, high precision 3D printing, development – an efficient method easy to scale up.


Fraunhofer ISC, IMT & IPQ KIT.


DFG Priority Program SPP1327 (2009 – 2014), grant HO2475/3-1 (Houbertz).

Cooperation with KIT IMT (Koos’ group) is gratefully acknowledged.


  1. Lindenmann, T. Hoose, S. Steenhusen, M.R. Billah, S. Köber,, R. Houbertz, Ch. Koos, Photonic Wire Bonding as an Enabling Technology for Multi-Chip Photonic Systems, SPIE Photonics West 8991-5 (2014).

On-Chip Waveguides

Key drivers for optical connectivity are the continuous increase in bandwidth and the tremendous energy consumption of data transfer in computing systems. The challenge is to provide scalability in optical packaging technology via a process which enables scalability in photonics integration. For a reduction of the power consumption in an operating computer system and an elimination of the excess heat generated from the system, optical waveguides are identified to solve these issues to some extent. Interconnect fabrication in different modes (line or helical fabrication) was carried out on-chip with tapered waveguides adiabatically coupled using Fraunhofer ISC’s equipment which was one of the ancestors of Multiphoton Optics’ equipment. Prior to fabrication of hot samples, parameter searches were performed with varying writing parameters, and a set of parameters out of theses searches was chosen for the fabrication of the interconnects. The chips were characterized at KIT with respect to their losses, with average losses over five nominal identical interconnects of -1 dB ± 0.28 dB. The best performing devices showed a loss of only -0.6 dB in the entire measurement range. Simulations of the coupling losses for two double tapers amount to 0.27 dB. These work was presented at SPIE’s Photonics West Conference in 2014.

Awards related to this application

Cowin Entrepreneurship Award for Outstanding Contribution to ICT Hardware & Smart Systems (Houbertz, MPO; Riester, formerly MPO) in 2014.

Towards Single-Mode Waveguides

As data transfer using multimode waveguides was demonstrated already very early in a joint cooperation of AT & S AG, Fraunhofer ISC, Joanneum Research, TU Wien. And Fraunhofer IOF in a real PCB environment for a VCSEL-PD coupling at 850 nm, the fabrication of single-mode waveguides was seen as very challenging and often required. In the course of a Priority Program SPP 1327, the first single-mode waveguides were fabricated by means of TPA at Fraunhofer ISC using visible light for the fabrication. Works with visible light started 2007, and materials were adapted to the processes and vice versa, providing the ability of using one material to serve as core and as cladding. This significantly lowers processing cost, and the Fraunhofer ISC Team involved has received the SPIE Green Photonics Award in the Category Optical Communication in 2013.

Partners in the Priority Program SPP1327 (2009 – 2014)

Houbertz (Fraunhofer ISC), Tünnermann (Fraunhofer IOF), Behrens (University of Hannover), Walles (University of Würzburg)

Funding is gratefully acknowledged, grant HO2475/3-1 (Houbertz).

Awards related to this application

SPIE Green Photonics Award in the Category Optical Communication (Houbertz, formerly Fraunhofer ISC, Steenhusen, Grunemann, Fraunhofer ISC)

Selected Presentations and Publications

  1. Houbertz, S. Steenhusen, M. Riester, SPIE Photonics West 8267-05 (2012).
  2. Steenhusen, R. Houbertz, M. Riester, SPIE Spring Meeting (2012).
  3. Riester, R. Houbertz, iLED Magazine, issue 9, Oct. 2013, p. 21
  4. Grunemann, Diploma Thesis, University of Würzburg (2012).

Reprint from Houbertz et al., Proc. SPIE 7053, 701308 (2008).

Photos of the Printed Circuit Board demonstrator (photo: Multiphoton Optics GmbH). In the lower image, the waveguides are still visible even after 10 yrs. being exposed to environmental conditions w/o any protecting measures.

Key Cooperation Partners

AT&S AG, Fraunhofer ISC, Joanneum Research, TU Wien, Fraunhofer IOF.


Funding from AT&S AG and cooperation with the involved partners is gratefully acknowledged.

Awards related to this application

Science Award of Steiermark/Austria for Nanoscienes and Nanotechnology in the Category Economic Applications (Riester & Langer, formerly AT&S AG) in 2006.

Joseph von Fraunhofer Award for the Integration of Optical Waveguides in Printed Circuit Boards in one material (Houbertz, formerly Fraunhofer ISC) in 2007.

SPIE Green Photonics Award in the Category Optical Communication (Houbertz, formerly Fraunhofer ISC, Steenhusen, Grunemann, Fraunhofer ISC) in 2013.

Cowin Entrepreneurship Award for Outstanding Contribution to ICT Hardware & Smart Systems (Houbertz, MPO; Riester, formerly MPO) in 2014.

Integrated Waveguides in Printed Circuit Boards

Driven by the high demand of bandwidth and efficiency considerations, a consortium of industrial and institutional partners has developed optical data connections which can be integrated into printed circuit boards (PCB), being fully compatible with the PCB technology. Starting in 2004/5, a material and a process was developed which fulfilled the requirements of an in situ fabricated multimode waveguide being implemented into PCB for mobile applications. The waveguides were used to couple a VCSEL to a photodiode, with waveguide bundles up to 12 cm. The fabrication was done at 20 mm/min via two-photon absorption (TPA) processing in the NIR regime with passive alignment only. In 2007/8, a BER of 10-9 at a data rate of 7 GB/s per channel was achieved. The uniqueness is not only based on TPA processing, but also on the special material composition. Only one individual material is necessary for planarization, dielectric, waveguide’s core and cladding. This means that the processing of several 10 steps was reduced to less than 5, whereas an integral thermal treatment step of the PCB production line is already used in this sequence.

Multiphoton Optics has continued to further develop a process that allows automation of high-precision optoelectronics assembly independently of the platform (Silicon Photonics chips, Triplex, Laser Dies, VCSELs, LEDs, among other components) in optical component packages. The process connects components by Photonic Interconnects with the required precision and repeatability. The Photonic interconnects are created in-situ, and they are ideally aligned to the exact location of the components. The technology allows scaling optical packaging operations to volume manufacturing. The process is compatible with standard assembly processes known from electronics manufacturing, and it can be adapted to customer requirements.

Selected Publications

  1. Houbertz, H. Wolter, V. Schmidt, L. Kuna, V. Satzinger, C. Wächter, G. Langer, Mat. Res. Soc. Symp. 1054, FF01-04 (2007).
  2. Houbertz, V. Satzinger, V. Schmidt, V. Leeb, G. Langer, Proc. SPIE 7053, 701308 (2008).

G. Schmid, W.R. Leeb, G. Langer, V. Schmidt, R. Houbertz, Electr. Lett. 45, 219 – 221 (2009).

Images are reprinted from J. Serbin, PhD Thesis, University of Hannover (2004).

Fabrication of Spot Size Converter and Waveguides, Photonic Crystal and Miscellaneous Structures

Materials play a crucial role in processing. Beginning end of 2000, Fraunhofer ISC and Laser Center Hannover LZH started a series of joint development projects to demonstrate the feasibility of TPA processing with functionalized materials. These materials were adapted to the processing conditions, and light-matter interaction was one of the key basics to be considered. Particularly for the employment of the technology in developing novel application scenarios at that time, a profound understanding of the mechanisms is necessary. In order to demonstrate the possibilities of Fraunhofer ISC’s materials and technologies with LZH’s capabilities in a more science-based view, projects were carried out several years, where applications in photonics were tackled such as spotsize converter, waveguide, and photonic crystal structure fabrication.

In the course of a Priority Program (SPP 1113), materials and processes were developed for photonic crystal applications. Refractive indices as high as 1.85 were achieved for materials which could be processed either with TPA, or with conventional UV lithography. Upon cross-linking of the photochemically active moieties, the material shrinks to some extent. As the structures are generated directly from a computer model, shrinkage compensation can be implemented similar to the production of ceramics, thus resulting in the correct shape after laser light exposure.

Apart from these application-related investigations, we were thrilled about the possibilities of the technique and more or less tried the 3D fabrication of whatever we found. In 2001 and 2002, we started to scale up the fabrication of structures already enormously, where we just exposed the outer shell of the structure to be fabricated, followed by a development step and used a subsequent UV exposure step to finally cross-link the entire structure. That was made possible by the unique understanding of the underlying processes, and demonstrated by a mm-sizes Venus figure.


Fraunhofer ISC, Laser Center Hannover LZH


DFG Priority Program SPP1113 Photonic Crystals (2003-2006), grant HO/2475/2-1 (Houbertz).

Cooperation with LZH is gratefully acknowledged.

Selected publicatons

  1. Serbin, B.N. Chichkov, R. Houbertz, Proc. SPIE 5222, 171 (2003).
  2. Serbin, A. Egbert, A. Ostendorf, B.N. Chichkov, R. Houbertz, G Domann, J. Schulz, C. Cronauer, L. Fröhlich, M. Popall, Opt. Lett. 28, 301 – 303 (2003).
  3. Houbertz, S. Cochet, G. Domann, M. Popall, J. Serbin, A. Ovsianikov, B.N. Chichkov, Nanotechnology Conference, MO31.06, Boston USA (2004).
  4. Serbin, PhD Thesis, University of Hannover (2004).
  5. Declerck, R. Houbertz, G. Jacopic, S. Passinger, B.N. Chichkov, Mat. Res. Soc. Symp. (2007).
  6. Houbertz, P. Declerck, S. Passinger, A. Ovsianikov, J. Serbin, B.N. Chichkov, in: Nanophotonic Materials, R.B. Wehrspohn, H.S. Kitzerow, K. Busch (eds.), Wiley VCH, Weinheim (2008).