Four years ago, the EU project PIX4life set out to mature an open access pilot line for silicon nitride integrated photonics, focused on life science applications. The synergies of industrial and academic project partners enabled the creation and validation of a unique pilot line using carefully selected demonstrator projects. Simultaneously, the software infrastructure (process design kits, design tools and building blocks) needed to enable early access of the pilot line through multi-project wafer (MPW) fabrication runs was created. After ten MPW fabrication runs in last three years at two foundries, and successful realization of dozens of designs from the project partners and the external customers, the pilot line is fully operational and ready for open access. In this presentation, we intend to share the experiences we have gained in setting up the pilot line, and to discuss the opportunities and challenges we can expect in future.
Visible diode lasers with wide wavelength tunability and narrow spectral linewidth are of high importance in bio-photonics and metrology. Hybrid integrated diode lasers, using waveguide circuits for spectrally selective feedback, provide wide tunability and sub-100-Hz intrinsic linewidths in a robust chip format. So far, these lasers have only been realized at infrared wavelengths. Here we present the first operation of a hybrid integrated diode laser in the visible. The laser, formed by a diode amplifier which is hybrid integrated with a Si3N4 ring-resonator based feedback circuit, is tunable over 11 nm around 685 nm and delivers 5 mW output power.
Ultra-narrow linewidth tunable hybrid integrated lasers are built from a combination of indium phosphide (InP) and silicon nitride-based TriPleX™. By combining the active functionality of InP with the ultra-low loss properties of the TriPleX™ platform narrow linewidth lasers in the C-band are realized. The InP platform is used for light generation and the TriPleX™ platform is used to define a long cavity with a wavelength-selective tunable filter. The TriPleX™ platform has the ability to adapt mode profiles over the chip and is extremely suitable for mode matching to the other platforms for hybrid integration. The tunable filter is based on a Vernier of micro-ring resonators to allow for single-mode operation, tunable by thermo-optic or stress-induced tuning. This work will show the operational principle and benefits of the hybrid lasers and the state of the art developments in the realization of these lasers. High optical powers ( <100 mW) are combined with narrow linewidth (< 1 kHz) spectral responses with tunability over a large (>100 nm) wavelength range and a low relative intensity (< -160 dB/Hz).
Evanescent field based integrated optics have great potential as a chip-based platform for label-free detection of molecular interactions. Implementation of the waveguides in an optical interferometric scheme allows for a very sensitive label-free sensor array platform as in this case small changes of the refractive index caused by the molecule capturing are easily detected. The unsurpassed sensitivity of especially the aMZI (asymmetric-Mach-Zehnder interferometer) sensor, in combination with the extreme uniformity of these sensing arrays allows for screening of proteins as well as small molecule drug candidates. However, to become interesting for the market, much more has to be in place: optimized surface functionalization chemistry, combination with microfluidics, and preferably hybrid integration of lightsource(s) and detector(s). In this proceedings the specific aMZI sensor chip design, surface modification, readout mechanisms and first results with multiplexing two specific cancer biomarker protein (POSTN and TGFBI) will be discussed. Initial experiments show a limit of detection of 1 ng/ml (~10 pM) of POSTN in buffer solution.
Photonic Integrated Circuit (PIC) technology is becoming more and more mature and the three main platforms that offer Multi Project Wafer runs (Indium Phosphide (InP), Silicon on Insulator (SOI) and the silicon nitride based TriPleX platform) each have their own unique selling points. New disruptive PIC based modules are enabled by combinations of the different platforms complementing each other in performance. In particular the InP-TriPleX combination are two very complementary technologies. Combining them together yields for instance tunable ultra-narrow linewidth lasers extremely suitable for telecom and sensing applications. Also microwave photonics modules for Optical Beam Forming Networks and 5G communication can, and have been realized with this combination. Important part of this combination is the integration of the different platforms in modules via cost effective assembly techniques. This talk will present the combination of both technologies, the interconnection issues faced in the assembly process and latest measurement results on these hybrid integrated devices.
Silicon-Nitride based Photonic Integrated Circuits (PICs) broaden the application scope of PICs outside of telecommunications where it originated from, since the wavelength range over which a waveguide can be designed matches for instance biophotonic applications usually working in the VIS (400-700nm) and NIR (700-1000nm) range. In this paper we show the latest results our silicon-nitride based sensor platform, that consist of an array of several types of interferometric sensors (Microring resonators, Mach-Zehnder interferometers), that are either used as refractive index, absorption or fluorescence sensors. We show the trade-offs between the different sensor types and show why an asymmetric MZI improves the sensitivity of the sensor platform over the MRR with over a factor of 10 down to the 10-8 RIU level. Furthermore we show that using flip-chipped VCSELs as integrated light source a low cost, disposable device is made. For desktop purposes we show how light sources are fiber coupled to the sensing platform creating a high end measurement system. The complete readout system allows for measuring multiple sensors on the chip, enabling multi-analyte measurements as well as improve the total stability of the measurement platform by using on-chip references. Finally we show an overview of measurement results where the sensor platform is functionalized using different interaction layers both local as well as wafer- scale. The results that the sensor platform can be used in for example liquid (blood and saliva) analysis as well as bacteria detection. The platform can be extended with a microfluidic interface for interaction of the optical layer and fluidics. An added integrated on-chip spectrometer allow additional functionality to the presented sensing platform.
Integrated-optical biosensors such as, for example, the microring resonator (MRR) and Mach-Zehnder interferometer, are more and more commercialized, mainly because of their high intrinsic sensitivity in combination with the possibilities they offer for integration in optofluidic devices. Previously, we have described the development and basic characteristics of MRR sensor chips that were fabricated in the TriPleX based silicon-nitride platform1 . In the present work, results are shown for the quantitative and sensitive detection of thrombin with aptamer-modified sensor chips. First, the modified MRR biosensor chips were tested for the binding and detection of thrombin using a repetitive number of binding/regeneration cycles on buffer sample containing 100 nM of thrombin. Then the binding curve was determined using different concentrations of thrombin, which revealed a limit of detection of 1 nM and a dynamic range up to roughly 0.5 μM of thrombin. Results from the thrombin binding experiment showed a stable performance during the course of multiple binding and regeneration cycles.
We are reporting on a Multi-Color Laser Engine (MLE) multiplexing four wavelengths (405 nm, 488 nm, 561 nm, 640 nm) by means of a Photonic Integrated Circuit (PIC) with Silicon Nitride (SiN) waveguides. Multiple building blocks are tested that allow manipulating the light in the waveguides to achieve fiber switching and variable optical attenuation. To slow down facet degradation and extend chip lifetime at near Ultra-Violet (UV) wavelengths (405 nm), a lateral endcap is implemented on chip and tested for reliability. Reasonable coupling and on-chip losses have been achieved in view of a practical use of the technology.
Photonics has become critical to life sciences. However, the field is far from benefiting fully from photonics' capabilities. Today, bulky and expensive optical systems dominate biomedical photonics, even though robust optical functionality can be realized cost-effectively on single photonic integrated circuits (PICs). Such chips are commercially available mostly for telecom applications, and at infrared wavelengths. Although proof-of-concept demonstrations for PICs in life sciences, using visible wavelengths are abundant, the gating factor for wider adoption is limited in resource capacity. Two European pilot lines, PIX4life and PIXAPP, were established to facilitate European R and D in biophotonics, by helping European companies and universities bridge the gap between research and industrial development. Through creation of an open-access model, PIX4life aims to lower barriers to entry for prototyping and validating biophotonics concepts for larger scale production. In addition, PIXAPP enables the assembly and packaging of photonic integrated circuits.
Photonic Integrated Circuits (PIC) will change the fundamental paradigms for the design of multi-color laser engines for life sciences. Exemplified with flow cytometry (FCM), integrated optical technology for visible wavelengths will be shown to open a new spectrum of possibilities to control flow cell illumination patterns, such as the number of output spots, the spot size, and even complex patterns generated by interferometry. Integration of additional optical functions such as variable optical attenuation, wavelength division multiplexing or fast shutters adds value to the PIC. TOPTICA is demonstrating integration of PICs in present Multi-color Laser Engine (MLE) architectures. Multiple wavelengths (405nm, 488nm, 561nm, 640nm) are coupled free space into the chip, leveraging its beam steering COOLAC (Constant Optical Output Level Auto Calibration) technology for automatic realignment, thus overcoming the need of fiber input delivery. Once in the waveguide, the light can be redirected and shaped to a desired output pattern and pitch, reducing the need of discrete optical components. In this work, we will discuss the implementation of various building blocks in PIC technology for MLEs and analyze the advantages over current macroscopic counterparts.
Photonic technology is increasingly used in applications in medicine, life and environmental science. Whereas currently many of these applications are implemented using some form of discrete (free-space) optics, much can be gained from a transition to Photonics Integrated Circuits. This follows the trends in the electronics industry where highly integrated electronic circuits have allowed the combination of many different functions in a small form factor. Just as it has done for the electronics industry, integrated optics will lead to smaller, cheaper, more reliable and more user friendly devices.
In this article a selection of highlights of the TriPleX™ technology of LioniX is given. The basic waveguide technology is explained with recent benchmark measurements done by University California Santa Barbara (UCSB) and University Twente (UT-TE). In order to show the low loss transparency over a wide wavelength range three examples of applications in different wavelength regimes are described in more detail. These are the Integrated Laser Beam Combiner (ILBC) of XiO Photonics in the visible light, a ringresonator sensing platform of LioniX around 850 nm and a phased array antenna with an Optical Beam Forming Network in the 1550 nm band. Furthermore it is shown that the technology is easily accessible via Multi Project Wafer Runs for which the infrastructure and design libraries are also set up.
We present a new class of low-loss integrated optical waveguide structures as CMOS-compatible industrial standard for photonic integration on silicon or glass. A TriPleXTM waveguide is basically formed by a -preferably rectangular- silicon nitride (Si3N4) shell filled with and encapsulated by silicon dioxide (SiO2). The constituent materials are low-cost stoichiometric LPVCD end products which are very stable in time. Modal characteristics, birefringence, footprint size and insertion loss are controlled by design of the geometry. Several examples of new applications will be presented to demonstrate its high potential for large-scale integrated optical circuits for telecommunications, sensing and visible light applications.
A new class of integrated optical waveguide structures ("TriPleX") is presented, based on low cost CMOS-compatible
LPCVD processing of alternating Si3N4 and SiO2 layers. The technology allows for medium and high index-contrast
waveguides that exhibit low channel attenuation. In addition, TriPleX waveguides are suitable for operation at
wavelengths from visible (< 500 nm) through the infra-red range (2 μm and beyond). The geometry is basically formed
by a rectangular cross-section of silicon nitride (Si3N4) filled with and encapsulated by silicon dioxide (SiO2). The
birefringence and minimal bend radius of the waveguide are completely controlled by the geometry of the waveguide
layer structures. Experiments on typical geometries show excellent characteristics for telecom wavelengths at ~1300 nm-1600 nm (channel attenuation ≤ 0.06 dB/cm, Insertion Loss (IL) ≤ 0.15 dB, Polarization Dependent Loss (PDL) ≤ 0.1 dB, Group Birefringence (Bg) << 1×10-4, bend radius ≤ 50-100 μm).
In the last years much effort has been taken to arrive at optical integrated circuits with high complexity and advanced functionality. For this aim high index contrast structures are employed that allow for a large number of functional elements within a given chip area: VLSI photonics. It is shown that optical microresonators can be considered as promising basic building blocks for filtering, amplification, modulation, switching and sensing. Active functions can be obtained by monolithic integration or a hybrid approach using materials with thermo-, electro- and opto-optic properties and materials with optical gain. Examples are mainly taken from work at MESA+.