Periodic Reporting for period 1 - FEMTOCHIP (FEMTOSECOND LASER ON A CHIP)
Reporting period: 2021-03-01 to 2022-02-28
Femtosecond lasers have enabled the direct measurement of optical frequencies and the realisation of optical clocks. Femtosecond lasers present a high potential for a wide range of applications. However, the technology’s large size and high cost restrict its development. The EU-funded FEMTOCHIP project will deliver a fully integrated chip-scale mode-locked laser with pulse energy, peak power and jitter specifications of a shoebox-sized fibre laser system. The innovation will enable several applications. The project will address key challenges to facilitate high pulse peak power and suppress Q-switching instabilities. Ultrashort pulse production is supported by on-chip dispersion compensation and artificial saturable absorption.
A modelling framework for amplifiers and mode-locked lasers has been set up. Extensive simulation studies have led to a first design of a mode-locked laser and its sub-components like integrated apodized chirped waveguide gratings or nonlinear artificial saturable absorbers as well as the rare earth doped amplifier have been developed. Dedicated high-Q micro-resonators have also been designed and are currently being fabricated. On the fabrication side, necessary processes have been implemented for the fabrication of SiN-integrated optical circuits and first test samples have been produced. For risk mitigation in fabrication of the amplifier gain materials RF sputtering deposition as well as atomic layer deposition is investigated to develop low loss gain waveguides for high gain modules. Here, also first crack-free samples providing low-loss and high-gain could be realized by RF sputtering. ALD deposition could be realized with a excellent thickness and refractive index uniformity of the Al2O3 film. Furthermore, first designs of low loss integrated delay lines for possible timing references and low loss interleavers for repetition rate multiplication have been designed and fabricated. First fabricated test structures and measurements lead already to further improvements. Several fabrication runs are on the way to enable optimization of the early designs and to realize a first demonstrator using 1.6 µm pumping.
There are numerous applications for the integrated low-noise femtosecond laser that will be developed in FEMTOCHIP. For brevity, we concentrate on few examples with commercial applications, with a large market volume that can benefit from the integrated technology: Currently, analogue-to-digital converters (ADCs), which are core elements in high-bandwidth ground- and space-based communication technologies, are limited by timing jitter related to the on-chip clocking, which is slightly below 100 fs. This timing jitter limits the sampling speed-resolution-product and has only experienced a modest rate of improvement over time by a factor of 4-8 every 10 years. The FEMTOCHIP (timing jitter < 1 fs) system can immediately boost ADC performance by 2 orders of magnitude, which in future work can reach single-attosecond timing jitter performance. Other applications with large markets are high-resolution LIDAR and RADAR systems for autonomous systems, where distance-resolution products critically depend on timing jitter. And even science applications like space-based synthetic aperture telescopes carrying synchronisation equipment based on integrated optical frequency combs can take a giant leap ahead and potentially answer: are we alone in the Universe?
Further obvious benefits:
-The FEMTOCHIP demonstrator will enlarge the market opportunities for LIGENTEC (especially in design and manufacturing of low-loss waveguides), with the existing customers and for all potential new end-users.
-FEMTOCHIP will provide the prerequisite laser system for many SMEs in their design and manufacturing process or as a source for their applications. This project helps SMEs to boost their innovation activities. All kind of markets within addressable applications can profit from FEMTOCHIP. This will therefore enable the progress and the interdisciplinarity in many fields.
-Added Value: When applying the FEMTOCHIP platform, users will gain knowhow about other disciplines and how they are interlinked. This knowledge can be included in their design and manufacturing process.
-New applications not foreseen: Since the FEMTOCHIP platform opens a completely new area within size and costs of ultrafast lasers, this will surely pave the way to new applications we cannot foresee up to now! What can be done with FEMTOCHIP within a smartphone? We will see!
Further obvious benefits:
-The FEMTOCHIP demonstrator will enlarge the market opportunities for LIGENTEC (especially in design and manufacturing of low-loss waveguides), with the existing customers and for all potential new end-users.
-FEMTOCHIP will provide the prerequisite laser system for many SMEs in their design and manufacturing process or as a source for their applications. This project helps SMEs to boost their innovation activities. All kind of markets within addressable applications can profit from FEMTOCHIP. This will therefore enable the progress and the interdisciplinarity in many fields.
-Added Value: When applying the FEMTOCHIP platform, users will gain knowhow about other disciplines and how they are interlinked. This knowledge can be included in their design and manufacturing process.
-New applications not foreseen: Since the FEMTOCHIP platform opens a completely new area within size and costs of ultrafast lasers, this will surely pave the way to new applications we cannot foresee up to now! What can be done with FEMTOCHIP within a smartphone? We will see!