GrapHICS focused project explores the low-cost and low-thermal-budget technology of hydrogenated amorphous Silicon (a-Si:H )in conjunction with the excellent electro-optical properties of Graphene (Gr) to demonstrate a new photonic platform that can be realized with CMOS processes. The demonstrator target device is an active MxN active router intended as a replacement of passive splitters used today in passive optical networks (PON). It will increase network design flexibility and scalability, while offering advantages in terms of cost, functionality and power consumption.
GrapHICS is part of Spoke 1 – Pervasive and Photonic Network Technologies and Infrastructures
Project PI: Francesco Giuseppe Della Corte
- A study on the characteristics of the possible silicon-on-insulator substrates to be employed for the project, was carried out.
- In addition, it has been conducted an extensive study on the effects of depositing a-Si:H on Graphene (Gr) using the PECVD technique. Partners have explored potential strategies to mitigate the impact of the process on Gr and gained valuable insights into the technique used to evaluate the quality of graphene, a-Si:H and interface. This preliminary investigation sets the stage for the upcoming experimental phase. 30-um-wide ring resonators were designed and fully characterized.
- A power-over-fiber scheme of energization of an active optical switch has been studied and experimentally verified. An optimized circuit was realized and experimental test of modulation were carried out on a Mach-Zehnder switch.
- Two integrated optic switches were designed: a microring resonator with straight and drop outputs, and a planar splitter working on the principle of adiabatic evolution of modes in tapered waveguides. The latter device will constitute the basic switch for the design of the switch matrix. In both cases, two waveguide dimensions were considered, a large- and a narrow-cross section waveguide.
- Gaining knowledge on the main technologies and process parameters used to deposit hydrogenated amorphous silicon. In particular, an extensive study was conducted on the effects of depositing a-Si:H on Graphene (Gr) using the PECVD technique. The main goal is that of understanding how this process alters the properties of Gr.
- Developing a solution for implementing the power-over-the-fiber architecture. A wide optical bandwidth photodiode was chosen and fully characterized, and a high efficiency dc-dc converter circuit was designed, realized and tested, which should be capable of providing up to 30 mW of power.
- Studying different devices for realizing spatial light switching, in order to select the most reliable and lower power one. Microring resonators, with parallel and serial configurations, multi-mode interference structures, digital optical switches based on adiabatic Y-splitters, have been considered so far. A study has started recently aiming at simulating the integration of Graphene layers as an active material to induce switching. Finally, plasma-optic effect was characterized for the first time in a-SiC, by observing resonance frequency shift in a 30-um-wide ring resonator under illumination.
- Designing single-mode and polarization independent a-Si/c-Si large cross-section waveguides.
- Fabrication process of the adiabatic large cross-section device started and laser writing technology has been proved effective for the definition of the integrated tapered waveguides. In view of embedding a Graphene capacitor as an active element within the waveguides, thin layers of TiO2 have been thermally evaporated on a Graphene layers. Raman measurements demonstrated the preservation of Graphene properties after the process.
Design, fabrication and characterization of a-Si:H-based ring resonators on a Silicon-on- Oxide substrate. The device also shows thermo-optic modulation, induced by Juole effect in a microheater made of Ti defined on its top surface by photolithography. At the telecommunication wavelength of 1550 nm, the thermo-optic modulator consumes an electric power of 3 mW to enable a resonance wavelength shift corresponding to a large modulation depth of about 96%.
Dynamic thermo-optic modulation was demonstrated at a switching frequency of 10 kHz with rise and fall times of 16 us and 13 us, respectively. Plasma-optic effect was also characterized in a-SiC:H.
Power-over-fiber scheme of energization of an active optical switch thoroughly studied and experimentally verified. In particular, the circuit components have been separately characterized and then modelled to be included in an SPICE-like electronic circuit simulation tool. The optimized circuit was then realized and experimental tests of modulation were carried out on a Mach-Zehnder switch.
A new integrated optical switch was designed and characterized by numerical simulations. The device is based on a planar splitter working on the principle of the adiabatic evolution of modes in tapered waveguides. The refractive index variation necessary to induce switching is compatible with that obtainable by changing the Fermi level in a Graphene/insulator/Graphene capacitor.
Deposition of good quality thin TiO2 layers via thermal evaporation onto Graphene layers, in view of embedding a Graphene capacitor inside waveguide, has been proven to preserve Graphene characteristics.
A driving circuit for switches, based on ultra-low power design techniques and microcontrollers, was realized and tested on real MZ-TO switches. The circuit also integrates the optical communication protocol for addressing switch configuration.
Papers:
E.D. Mallemace, Y.L., X. Shi, D. Chaussende, V. Tabouret, S. Rao, H. Ou, F. G. Della Corte, Amorphous silicon-carbide modulator based on the thermo-optic effect, ICSCRM - International Conference on Silicon Carbide and Related Materials 2023, 17-22 September 2023, Sorrento, Italy
Rao, S., Mallemace, E.D., Faggio, G. et al. Experimental characterization of the thermo-optic coefficient vs. temperature for 4H-SiC and GaN semiconductors at the wavelength of 632 nm. Sci Rep 13, 10205 (2023). https://doi.org/10.1038/s41598-023-37199-6
B. Hashemi, S. Rao, M. Casalino, Francesco Della Corte, 2Design and Simulation of Single-Mode and Polarization Independent Deeply Etched Amorphous Silicon on SOI Waveguides, Photoptics 2024 Conference, Rome 21-23 Feb 2024
Dynamic thermo-optic modulation was demonstrated at a switching frequency of 10 kHz with rise and fall times of 16 us and 13 us, respectively. Plasma-optic effect was also characterized in a-SiC:H.
Power-over-fiber scheme of energization of an active optical switch thoroughly studied and experimentally verified. In particular, the circuit components have been separately characterized and then modelled to be included in an SPICE-like electronic circuit simulation tool. The optimized circuit was then realized and experimental tests of modulation were carried out on a Mach-Zehnder switch.
A new integrated optical switch was designed and characterized by numerical simulations. The device is based on a planar splitter working on the principle of the adiabatic evolution of modes in tapered waveguides. The refractive index variation necessary to induce switching is compatible with that obtainable by changing the Fermi level in a Graphene/insulator/Graphene capacitor.
Deposition of good quality thin TiO2 layers via thermal evaporation onto Graphene layers, in view of embedding a Graphene capacitor inside waveguide, has been proven to preserve Graphene characteristics.
A driving circuit for switches, based on ultra-low power design techniques and microcontrollers, was realized and tested on real MZ-TO switches. The circuit also integrates the optical communication protocol for addressing switch configuration.
Papers:
E.D. Mallemace, Y.L., X. Shi, D. Chaussende, V. Tabouret, S. Rao, H. Ou, F. G. Della Corte, Amorphous silicon-carbide modulator based on the thermo-optic effect, ICSCRM - International Conference on Silicon Carbide and Related Materials 2023, 17-22 September 2023, Sorrento, Italy
Rao, S., Mallemace, E.D., Faggio, G. et al. Experimental characterization of the thermo-optic coefficient vs. temperature for 4H-SiC and GaN semiconductors at the wavelength of 632 nm. Sci Rep 13, 10205 (2023). https://doi.org/10.1038/s41598-023-37199-6
B. Hashemi, S. Rao, M. Casalino, Francesco Della Corte, 2Design and Simulation of Single-Mode and Polarization Independent Deeply Etched Amorphous Silicon on SOI Waveguides, Photoptics 2024 Conference, Rome 21-23 Feb 2024
The ultimate goal of GrapHICS it to accelerate the route to market for breakthrough innovations, and ultimately to contribute to reaching the ambitious objectives of sustaining industrial competitiveness and leadership in the rapidly growing photonic market of Fiber-to-the-Home (FTTH). It covers the integration of high-speed electronic circuits with photonics by blending both fields with a seamless integration platform. Moreover, by overcoming the limitation of current passive components, solutions developed in this Project will be also well suited for advanced computing and other applications. The strategic participation of a network company as OpenFiber witnesses the relevance of the challenging targets of the Project, both in terms of network operation and energy savings.
E.D. Mallemace, Y.L., X. Shi, D. Chaussende, V. Tabouret, S. Rao, H. Ou, F. G. Della Corte, Amorphous silicon-carbide modulator based on the thermo-optic effect,
ICSCRM - International Conference on Silicon Carbide and Related Materials 2023,
17-22 September 2023, Sorrento, Italy
A power-over-fiber scheme of energization of an active optical switch was successfully implemented in a laboratory environment. The circuit components have been separately characterized and then modelled to be included in an electronic circuit simulation tool (SPICE-like). The optimized circuit was then realized and experimental test of modulation were carried out on a Mach-Zehnder switch.
A power-over-fiber scheme of energization of an active optical switch was successfully implemented in a laboratory environment. The circuit components have been separately characterized and then modelled to be included in an electronic circuit simulation tool (SPICE-like). The optimized circuit was then realized and experimental test of modulation were carried out on a Mach-Zehnder switch.
- Papers on Q1 journals
- expected: 6
- accomplished: 1
- readiness: 50%
- Communications at international conferences
- expected: 6
- accomplished: 3
- readiness: 150%
- Scientific journal papers with at least two partners
- expected: 5
- accomplished: 1
- readiness: 80%
- Prototypes (wide bandwidth integrated switch matrix)
- expected: 1
- accomplished: 0
- readiness: 0%
- Dedicated workshops within international conferences
- expected: 1
- accomplished: 0
- readiness: 0%
- MSc students involved
- expected: 6
- accomplished: 3
- readiness: 100%
- seminars/information days for BSc/MSc students
- expected: 1
- accomplished: 2
- readiness: 100%
- Publications
- expected: 12
- accomplished: 7
- Readiness level: 66%
- Joint Publications
- expected: 5
- accomplished: 4
- Readiness level: 80%
- Talks/Dissemination events
- expected: 3
- accomplished: 2
- Readiness level: 66%
- Demo/PoC
- expected: 1
- accomplished: 0
- Readiness level: 0%
- Project Meetings
- expected: 6
- accomplished: 4
- Readiness level: 100%
- Patents/Innovations
- expected: 0
- accomplished: 0
- Readiness level: -
- Open source contributions
- expected: 0
- accomplished: 0
- Readiness level: -
- Standardization contributions
- expected: 0
- accomplished: 0
- Readiness level: -
- seminars/information days for BSc/MSc students
- expected: 1
- accomplished: 2
- readiness: 100%
Researchers involved: 70
Collaboration proposals
The project is open to collaborations on the following topics:
- Green optical network architectures.
- Novel materials and novel photonic integrated circuits for datacom.
- Physical layer modeling and capacity scaling in optical communication system
For any proposal of collaboration within the project please contact the project PI.