Periodic Reporting for period 1 - CompADC (Sub-Terahertz Analog-to-Digital Conversion Using Integrated Soliton Microcombs)
Reporting period: 2020-12-01 to 2022-11-30
Optical frequency combs, a Nobel Prize winning technology, provide a powerful tool to enable unprecedented precise measurements of frequency and time and allow for phase coherent link of optical and radio frequencies. Stable and coherent optical frequency combs represent in the time domain a unique type of mode-locked emission of optical pulses. The recent series of breakthroughs in compact optical frequency combs, particularly temporal dissipative Kerr soliton (DKS) microcombs, opened up a new way to generate high-coherence, high-repetition-rate optical frequency combs in compact microresonators, providing a promising technology to replace bulky mode-locked lasers (MLLs) and overcome the fundamental timing jitter limit of electronic analog-to-digital converters (ADCs). However, integrated soliton microcombs with high coherence, high repetition rates, and sufficient power for photonic ADCs remained largely unexplored.
To solve these challenges, the project “Sub-Terahertz Analog-to-Digital Conversion Using Integrated Soliton Microcombs (CompADC)” aimed to demonstrate integrated soliton microcomb sources with repetition rates, high coherence, and high power for the applications in photonic-assisted analog-to-digital conversion (ADC). The innovative approach planned in the CompADC project was to implement a novel photonic integrated circuit that can generate Kerr-based soliton microcombs that can satisfy the requirement for the demonstration of a high-speed microwave photonic ADC with the improved effective number of bits.
CompADC has achieved significant research output, such as fully integrated high-power soliton microcomb sources, and fully integrated single-mode, tunable lasers as optical LOs. Thes results can fundamentally solve the issues of the CompADC system but also, viewed more broadly, novel coherent communication receivers and LiDAR engines. Therefore, the CompADC project provided a venue to discover new technical challenges and has propelled the researcher and the host lab to carry out ground-breaking research results and disruptive solutions.
To solve these challenges, the project “Sub-Terahertz Analog-to-Digital Conversion Using Integrated Soliton Microcombs (CompADC)” aimed to demonstrate integrated soliton microcomb sources with repetition rates, high coherence, and high power for the applications in photonic-assisted analog-to-digital conversion (ADC). The innovative approach planned in the CompADC project was to implement a novel photonic integrated circuit that can generate Kerr-based soliton microcombs that can satisfy the requirement for the demonstration of a high-speed microwave photonic ADC with the improved effective number of bits.
CompADC has achieved significant research output, such as fully integrated high-power soliton microcomb sources, and fully integrated single-mode, tunable lasers as optical LOs. Thes results can fundamentally solve the issues of the CompADC system but also, viewed more broadly, novel coherent communication receivers and LiDAR engines. Therefore, the CompADC project provided a venue to discover new technical challenges and has propelled the researcher and the host lab to carry out ground-breaking research results and disruptive solutions.
Objectives of CompADC are the following:
1. Generation of dual dissipative Kerr soliton combs in two Si3N4 photonic-chip-based microresonators on the same photonic chip, with ultra-low jitter, high mutual coherence, and distinct repetition rates.
2. Demonstration of a high-performance microwave photonic link to perform 100 GHz analog-to-digital conversion using a dual-microcomb scheme.
Overall, the project has fully achieved its objectives and milestones for the period. In particular, we have accomplished the following milestones:
We have accomplished the following milestones:
1. Generation of photonic integrated circuits for on-chip optical amplification.
2. Generation of frequency-locked, low-jitter soliton microcombs (100 GHz and 20 GHz comb spacing) on chip with high output power.
3. Generation of low-noise integrated lasers as the basis of the optical local oscillator and the mode-locked laser for photonic ADCs.
4. Demonstration of photonic sampling of electrical signals using amplified soliton microcombs with 100 GHz comb spacing. (electro-optic modulation and coherent detection experiments)
Deliverables of CompADC include:
1. Publications of integrated soliton microcombs and on-chip optical amplifiers.
2. Publications of low-noise laser sources desirable for optical LOs (local oscillators) in the photonics-assisted ADC.
The research results achieved by this project have been published in high impact journals, mianly Science and are currently under review at Nature Photonics. In addition, the beneficiary has attended several academic conferences, giving 3 invited oral presentations on these research results.
1. Generation of dual dissipative Kerr soliton combs in two Si3N4 photonic-chip-based microresonators on the same photonic chip, with ultra-low jitter, high mutual coherence, and distinct repetition rates.
2. Demonstration of a high-performance microwave photonic link to perform 100 GHz analog-to-digital conversion using a dual-microcomb scheme.
Overall, the project has fully achieved its objectives and milestones for the period. In particular, we have accomplished the following milestones:
We have accomplished the following milestones:
1. Generation of photonic integrated circuits for on-chip optical amplification.
2. Generation of frequency-locked, low-jitter soliton microcombs (100 GHz and 20 GHz comb spacing) on chip with high output power.
3. Generation of low-noise integrated lasers as the basis of the optical local oscillator and the mode-locked laser for photonic ADCs.
4. Demonstration of photonic sampling of electrical signals using amplified soliton microcombs with 100 GHz comb spacing. (electro-optic modulation and coherent detection experiments)
Deliverables of CompADC include:
1. Publications of integrated soliton microcombs and on-chip optical amplifiers.
2. Publications of low-noise laser sources desirable for optical LOs (local oscillators) in the photonics-assisted ADC.
The research results achieved by this project have been published in high impact journals, mianly Science and are currently under review at Nature Photonics. In addition, the beneficiary has attended several academic conferences, giving 3 invited oral presentations on these research results.
The CompADC project has resulted in the significant breakthroughs in photonic integrated circuit-based Erbium-based amplifier and laser technology which is a long-anticipated goal that was never demonstrated. Therefore, the CompADC project provided a venue to discover new technical challenges and has propelled the researcher and the host lab to carry out ground-breaking research results and disruptive solutions. The full development of a novel integrated high-power, low-noise mode-locked microcomb source will be the next breakthrough, and it can naturally lead us to demonstrate a record-high performance photonic ADC, coherent transceiver, and LiDAR engines in the future.
The impact of this project includes:
1. The CompADC project has accomplished a significant breakthrough in the frequency-comb-based microwave generation technique, which was considered an important direction not only for the host group but also for the entire microresonator frequency comb community. With the outstanding research results obtained from the project, CompADC will have substantial impacts on the research field of microresonator frequency combs.
2. The research output of the CompADC project opens up a multi-disciplinary research field lying at the interface of integrated photonics, nonlinear optics, and amplifier & laser physics, producing profound impacts in both academia and industry. It is envisaged to find widespread applications not only in photonic ADC but also in coherent WDM communications, LiDAR and sensing, which will result in the growth of the startup companies and job opportunities in Europe. Moreover, the research results have produced valuable intellectual properties.
3. The demonstrations and the devices have raised the significant interest of the industry and companies who have approached the researcher and the host PI and expressed interest in further collaboration and commercialization. The applicant will transition the research breakthroughs to industrial products and applications, contributing to the growth of companies and economic growth and to the sustainable environment development in Europe.
To the European Union, CompADC has also made contributions to the EU H2020 program in excellence research, proving that Europe continues to produce world-class science, and being among the first to advance optical frequency comb technologies.
The impact of this project includes:
1. The CompADC project has accomplished a significant breakthrough in the frequency-comb-based microwave generation technique, which was considered an important direction not only for the host group but also for the entire microresonator frequency comb community. With the outstanding research results obtained from the project, CompADC will have substantial impacts on the research field of microresonator frequency combs.
2. The research output of the CompADC project opens up a multi-disciplinary research field lying at the interface of integrated photonics, nonlinear optics, and amplifier & laser physics, producing profound impacts in both academia and industry. It is envisaged to find widespread applications not only in photonic ADC but also in coherent WDM communications, LiDAR and sensing, which will result in the growth of the startup companies and job opportunities in Europe. Moreover, the research results have produced valuable intellectual properties.
3. The demonstrations and the devices have raised the significant interest of the industry and companies who have approached the researcher and the host PI and expressed interest in further collaboration and commercialization. The applicant will transition the research breakthroughs to industrial products and applications, contributing to the growth of companies and economic growth and to the sustainable environment development in Europe.
To the European Union, CompADC has also made contributions to the EU H2020 program in excellence research, proving that Europe continues to produce world-class science, and being among the first to advance optical frequency comb technologies.