Periodic Reporting for period 2 - INSPIRE (InP on SiN Photonic Integrated circuits REalized through wafer-scale micro-transfer printing)
Reporting period: 2022-07-01 to 2023-06-30
INSPIRE aims to revolutionize photonic integrated circuit technology by combining two technologies, InP photonics and SiN photonics, in a single platform through wafer-scale micro-transfer printing technology. This platform will enable the combination of high-performance III-V opto-electronic components (semiconductor optical amplifiers, high-speed phase modulators and photodetectors) operating in the C-band with the high-performance passive functionality of the SiN platform (high performance filters, 5 dB/m waveguide loss), on 200 mm wafers. The micro-transfer printing integration approach enables high-throughput integration of III-V devices on SiN photonic integrated circuits with better than 1-µm alignment accuracy, resulting in high-performance, low-cost photonic integrated circuits. The INSPIRE technology is in principle applicable in a wide range of mega-markets, and will be validated by three representative use cases: the case of a distributed fiber sensing readout unit, the case of a microwave photonics RF pulse generator, and a datacenter switch fabric. Compact models of the III-V opto-electronic components will be developed, enabling designers to exploit this platform for a wide range of applications. INSPIRE will sustain Europe’s industrial leadership in photonics by combining the generic integrated foundry technology at the pioneering pure-play foundry SMART Photonics, and the silicon photonics pioneer imec, with the micro-transfer printing technology at X-Celeprint, making this a world-first platform combining the strengths of all known PIC manufacturing platforms. It will also strengthen the European manufacturing base by developing and implementing processing steps that are key to removing expensive assembly steps in photonic IC based product realization. The methods will be developed for silicon nitride – indium phosphide integration. Since the optical coupling happens through a silicon intermediate layer, the developed technology can be ported to silicon CMOS photonics as well.
The work in the first 30 months mainly focused on designing and fabricating a first SiN and InP run, including designs for Demonstrators, developing the µTP technique further, and designing a second run. Initial building block and Demonstrator results were obtained.
Novel components have been designed, to be implemented on INSPIRE runs. An efficient and tolerant coupler, to convert the optical mode from the SiN to the InP waveguide, has been designed and implemented on the second INSPIRE run. Electrodes have been optimized for high-speed operation and a 100-GHz modulator has been designed. A thermal analysis has been done to design closely-spaced SOA arrays, for dense integration.
The fabrication of the first SiN run has been completed and the waveguides and building blocks have been characterized. These served as a benchmark for further Demonstrator design and an updated second SiN run, which is now taped out. The fabrication of the first InP run suffered from open circuits in the electrical contacts, preventing us from characterizing the active components, such as SOAs and modulators. Passive components for testing mode conversion and insertion loss are being printed for further characterization. A new process flow has been designed for the second InP run.
With respect to the µTP technique development, we have realized successful printing of InP coupons on SiN with an accuracy better than 1 µm at sample scale. We have started preliminary work for wafer scale printing.
The Demonstrators, i.e. fiber sensor interrogator, microwave photonic engine, and datacenter switch, have been designed for the first and second run. Using the SiN dies from the first run, complemented with legacy InP coupons, a 20-GHz FMCW, 2-kHz optical linewidth fully integrated laser was experimentally shown, with beyond-state-of-the-art performance. The passive SiN filters hit the target metrics. The switch was packaged, but had too limited gain for system demonstration.
With respect to exploitation, the initial InP process to realize coupons for µTP has been transferred to and set up at SMART Photonics. Some INSPIRE partners are key participants in the new KDT photonixFAB Pilot Line, laying out the path for further TRL scaling of the µTP process, beyond INSPIRE targets. A benchmark study was conducted to make sure the INSPIRE target metrics are (still) relevant and lead to a competitive technology and Demonstrators.
Novel components have been designed, to be implemented on INSPIRE runs. An efficient and tolerant coupler, to convert the optical mode from the SiN to the InP waveguide, has been designed and implemented on the second INSPIRE run. Electrodes have been optimized for high-speed operation and a 100-GHz modulator has been designed. A thermal analysis has been done to design closely-spaced SOA arrays, for dense integration.
The fabrication of the first SiN run has been completed and the waveguides and building blocks have been characterized. These served as a benchmark for further Demonstrator design and an updated second SiN run, which is now taped out. The fabrication of the first InP run suffered from open circuits in the electrical contacts, preventing us from characterizing the active components, such as SOAs and modulators. Passive components for testing mode conversion and insertion loss are being printed for further characterization. A new process flow has been designed for the second InP run.
With respect to the µTP technique development, we have realized successful printing of InP coupons on SiN with an accuracy better than 1 µm at sample scale. We have started preliminary work for wafer scale printing.
The Demonstrators, i.e. fiber sensor interrogator, microwave photonic engine, and datacenter switch, have been designed for the first and second run. Using the SiN dies from the first run, complemented with legacy InP coupons, a 20-GHz FMCW, 2-kHz optical linewidth fully integrated laser was experimentally shown, with beyond-state-of-the-art performance. The passive SiN filters hit the target metrics. The switch was packaged, but had too limited gain for system demonstration.
With respect to exploitation, the initial InP process to realize coupons for µTP has been transferred to and set up at SMART Photonics. Some INSPIRE partners are key participants in the new KDT photonixFAB Pilot Line, laying out the path for further TRL scaling of the µTP process, beyond INSPIRE targets. A benchmark study was conducted to make sure the INSPIRE target metrics are (still) relevant and lead to a competitive technology and Demonstrators.
The development of the INSPIRE platform, including novel component designs, has started and has led to first experimental results, including on-spec passive components, and a low-noise frequency-modulated laser with beyond state-of-the-art performance. Due to fabrication issues with the InP runs, more extensive experimental results are only expected beginning of 2024.
It is anticipated that the INSPIRE platform will boost state of the art in micro-transfer printing in three ways. First this is done by improving the quality of the individual components, more specific increasing the gain and the bandwidth of the InP actives, while keeping the loss of the SiN passives low. Secondly this is done by increasing the integration density of the actives, by combining multiple components on a coupon. Thirdly this is done by improved alignment accuracy, for lower overall insertion loss.
This in turn leads to lower loss complex circuits, which enables higher integration density and/or lower noise operation. The three selected demonstrators, i.e. datacenter switch, microwave photonics engine and fiber sensor readout, are all critically enabled by these INSPIRE capabilities. At the same time, these demonstrators are relevant for large markets, such as wireless communications, datacenter communications and structural sensing, thus ensuring maximum impact of the INSPIRE technology.
It is anticipated that the INSPIRE platform will boost state of the art in micro-transfer printing in three ways. First this is done by improving the quality of the individual components, more specific increasing the gain and the bandwidth of the InP actives, while keeping the loss of the SiN passives low. Secondly this is done by increasing the integration density of the actives, by combining multiple components on a coupon. Thirdly this is done by improved alignment accuracy, for lower overall insertion loss.
This in turn leads to lower loss complex circuits, which enables higher integration density and/or lower noise operation. The three selected demonstrators, i.e. datacenter switch, microwave photonics engine and fiber sensor readout, are all critically enabled by these INSPIRE capabilities. At the same time, these demonstrators are relevant for large markets, such as wireless communications, datacenter communications and structural sensing, thus ensuring maximum impact of the INSPIRE technology.