Showing papers by "Pu Jian published in 2022"
TL;DR: In this article , the most recent advances in design and fabrication have improved the performance of FMFs and MDM systems, and allowed to turn research demonstrations into practical deployments, and showed how these advances can be used to improve the performance.
Abstract: Mode-division multiplexing (MDM) using few-mode fibers (FMFs) appears as a promising technology to increase fiber capacity by a few orders of magnitude and sustain the traffic demand for the decades to come. The potential of MDM lies in its ability to exploit multiple modes within a single optical fiber strand. Since 2011 and the first promising demonstrations, impressive progress has been made. In this article, we will show how the most recent advances in design and fabrication have improved the performance of FMFs and MDM systems, and allowed to turn research demonstrations into practical deployments.
4 citations
TL;DR: In this article , a Laguerre Gaussian basis is used to decompose a fundamental Gaussian beam transmitted behind an absorbing propeller-like object, where the main contributing components correspond to modes having the same rotational symmetry as the object, thus enabling pattern recognition.
Abstract: We investigate both theoretically and experimentally the decomposition of a fundamental Gaussian beam transmitted behind an absorbing propeller-like object. We use a Laguerre Gaussian basis which modes carry orbital angular momentum. The main contributing components correspond to modes having the same rotational symmetry as the object, thus enabling pattern recognition. When the object is rotated, the frequency of the modes of the basis experiences a rotational Doppler shift characterizing the movement, that can be easily detected. Potential applications in target recognition and rotation identification are then considered, including rotational Doppler shifts using microwaves.
1 citations
01 Apr 2022
TL;DR: In this paper , a fully reflective beam splitter compatible with 500fs green USP laser is presented, and the process results including the repeatability of the pattern and the achievable ablation rate are presented.
Abstract: Laser microprocessing using Ultra-Short Pulse lasers has developed thanks to the achieved process quality. The main challenge of those processes is the yield improvement. This study will focus on yield improvement of applications such as such as probe card manufacturing for electronic applications with a green USP laser using beam splitting. We present here a fully reflective beam splitter compatible with 500fs green lasers. The compatibility with an industrial machine is demonstrated through a F-theta lens, as well as through a precession head. We show here the process results including the repeatability of the pattern, and the achievable ablation rate.
1 citations
14 Jun 2022
TL;DR: In this article , the rotational Doppler shift of a fundamental laser light reflected on an ideal rotating propeller was investigated and it was shown that only modes having the same rotational symmetry as the propeller are involved in the decomposition.
Abstract: The rotational Doppler shift is the counterpart of the usual linear Doppler effect for rotating bodies. We study by an experimental approach coupled with theoretical considerations the rotational shift of a fundamental laser light reflected on an ideal rotating propeller. We decompose the reflected light on a Laguerre–Gaussian basis and show that only modes having the same rotational symmetry as the propeller are involved in the decomposition. The latter experience a frequency shift proportional to the rotation frequency of the propeller and the topological charge of the beam. Extensions of this work in the microwave domain are then considered.
1 citations
15 Jan 2022
TL;DR: In this article , a Laguerre Gaussian basis is used to decompose a fundamental Gaussian beam transmitted behind an absorbing propeller-like object, where the main contributing components correspond to modes having the same rotational symmetry as the object, thus enabling pattern recognition.
Abstract: We investigate both theoretically and experimentally the decomposition of a fundamental Gaussian beam transmitted behind an absorbing propeller-like object. We use a Laguerre Gaussian basis which modes carry orbital angular momentum. The main contributing components correspond to modes having the same rotational symmetry as the object, thus enabling pattern recognition. When the object is rotated, the frequency of the modes of the basis experiences a rotational Doppler shift characterizing the movement, that can be easily detected. Potential applications in target recognition and rotation identification are then considered, including rotational Doppler shifts using microwaves.
1 citations
01 Apr 2022
TL;DR: In this article , a non-coherent beam combiner of 4 Fibered high power input beams at 1µm with a total Mµ close to 2,5 and a combining efficiency around 92%.
Abstract: Incoherent beam combination consists of superposing several laser beams on a target. This technique is relatively simple to implement and uses "off-the-shelf" optical components, without active control of the phase or polarization of the input sources. With the Multi-plane Light Conversion (MPLC) technique, tailored and multi-reflective phase element, enabling to obtain an optimal beam quality in terms of divergence for a given number of input beams, we present non-coherent beam combiner of 4 Fibered high power input beams at 1µm with a total M² close to 2,5 and a combining efficiency around 92%.
01 Apr 2022
TL;DR: In this paper , a fully reflective system for high quality Bessel beam generation using a fully-reflective system has been described, which presents an intensity plateau along its propagation axis, being twice more homogeneous and having a five times sharper tail compared to a classical Besselbeam.
Abstract: Complex touch panel displays development is requiring high performance glass cutting techniques. Femtosecond lasers, combined to Bessel beam generation based on reflective axicons already showed quality and efficiency improvements, while being able to handle high peak and average power. We described here recent developments for high quality Bessel beam generation using a fully reflective system. This complex Bessel beam presents an intensity plateau along its propagation axis, being twice more homogeneous and having a five times sharper tail compared to a classical Bessel beam. This development paves the way to complex and selective multi-layer glass cutting.
01 Apr 2022
TL;DR: In this paper , a beam shaper compatible with industry standard equipment handling up to 16kW average power delivering an optimized non-symmetric shape is described, enabling to reconstruct the cutting front and to calculate the absorbed irradiance on the processed sample.
Abstract: Laser cutting process is a very broad application requesting a high beam quality. Optimizing the beam shape is a promising solution to the challenge of cutting thicker parts while maintaining a sufficient cutting speed. We describe here a beam shaper compatible with industry standard equipment handling up to 16kW average power delivering an optimized non-symmetric shape. The different shapes are examined by means of online high-speed X-ray images, enabling to reconstruct the cutting front and to calculate the absorbed irradiance on the processed sample. This allows to compare the results with conventionally processed samples.
01 Apr 2022
TL;DR: In this article , a non-coherent beam combiner for QCL with optimal beam quality is presented, demonstrating the state-of-the-art performance in terms of M2.
Abstract: The ability to combine incoherent sources with attractive performances enable hardware integration issues to be resolved using stable, good quality off-the-shelf components. Some new generation imaging systems can be found in the mid-infrared (MIR). The most portable laser technology at this range, our Quantum Cascade Laser source can provide light power of around 2 W, industrial grade. With the Multi-plane Light Conversion technique and a modal approach, we present non-coherent beam combiner for QCL with optimal beam quality, demonstrating the state of the art in terms of M2.