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Reference : UPR8001-VERBAR-005
Workplace : TOULOUSE
Date of publication : Monday, September 13, 2021
Type of Contract : FTC Scientist
Contract Period : 18 months
Expected date of employment : 15 November 2021
Proportion of work : Full time
Remuneration : Between 2663 and 3783 gross monthly depending on experience
Desired level of education : 5-year university degree
Experience required : 1 to 4 years
The national research project "3D-BEAM-FLEX" aims at demonstrating a new way for fabricating a continuous, self-aligned and flexible waveguide between a VCSEL and a single-mode fiber. Our patented method exploits self-writing mechanisms in novel NIR photosensitive materials and relies on a two-step photo-fabrication process in NIR/UV ranges. Promising results have been recently obtained on the coupling of two optical fibers in the visible range.
The objective of this work is to experimentally and theoretically demonstrate the interest of this new method for VCSEL-to-fiber coupling in the NIR range.
Our "digital society" relies more and more on remote high speed communications. In this context, the design and the development of efficient and low cost optical interconnects is crucial. VCSELs (vertical cavity surface emitting laser diodes) operating in the near-infrared range (NIR) are key photonic sources for these systems. This is due to their numerous advantages, such as low power consumption, parallel operation and high modulation rate capacity. However, coupling a VCSEL device to a singlemode optical fiber is still a long and costly operation, due to poor tolerances to axial and lateral misalignments and it often requires the use of external optical coupling elements. Moreover, in most applications, a simple and collective method is still missing to fabricate a "bent" optical link, in which the vertical beams emitted by VCSEL arrays could be redirected in the horizontal plane of the optical fibers in a compact optical module.
The possible applications of such optical links not only concern optical communications systems, but also miniaturized spectroscopy and compact sensors.
The first step will be to take part to the design and the development of a new kind of multi-axis alignment optical bench. Thanks to this set-up, the photonic and photochemical conditions for waveguide fabrication will be studied, first at a standard wavelength, 850nm (for datacom applications) and in a second step, at longer wavelengths, 1.31 µm and 1.55 µm (for telecom applications).
Experimental results will be compared to those given by modeling using a numerical waveguiding simulation tool. Several initial configurations will be considered (mode size, axial distance and lateral misalignments, photopolymer composition, exposure times) to determine the best conditions and to prove the efficiency of the method. The studied devices will be prepared and characterized in the LAAS clean room facilities.
Finally, new potentialities offered by additive manufacturing (3D printing) will also be explored in order to integrate the best flexible self-written link in a compact polymer optical module that can be foldable at 90° and used in a real system.
The candidate should hold a PhD in physics/optics and a solid background in guided-wave optics, optoelectronics and photonics, as well as a strong interest in experimental work and optical characterization.
The working languages of the team are English or French.
Please send a CV, a motivation letter and a list of two references.
Applications that do not match the required skills will not be considered.
This research work will be led within the MICA team of LAAS-CNRS lab, a unit of the Centre National de la Recherche Scientifique (CNRS) in Toulouse, France, (https://www.laas.fr/public/en/vcsel-based-optical-microsystems) with the help of our technological and characterization platforms and in close collaboration with IS2M-CNRS lab (https://www.is2m.uha.fr/en/home-2/) for materials aspects.
Constraints and risks
Optical experiments. Laser risks. Possible work in LAAS cleanroom.
The starting date depends on the administrative delays linked to ZRR process (restrictive access zone) which are at the maximum 2 months after the date of application.
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