Development of a 60 w pulsed fiber laser amplifier for materials processing

Download
2014
Aydın, Yiğit Ozan
Fiber lasers have the advantage of high beam quality, high efficiency, small size, air cooling and therefore much interest in the development of high power fiber laser systems have arisen recently in the world. Almost all commercially developed fiber lasers with nanosecond pulse duration, that are being used for material processing, are Q-switched systems. Vital parameters in the material processing such as repetition rate, pulse energy and pulse duration are correlated with each other and they cannot be adjusted independently in the Q-switch mechanism. In this study, ytterbium doped all-fiber laser amplifier with 60 W average power and more than 20 kW peak power at 1 μm wavelength was developed, and its potential for processing of different material types is investigated. This master-oscillator power-amplifier (MOPA) architectured system is composed of pulses, produced by an electronically pumped diode, and amplified by a series of fiber amplifiers. In contrast with Q-switch lasers, MOPA architecture allows us to adjust pulse duration, repetition rate and power independently. Beam quality is nearly diffraction limited, and the typical M2 value is1.5. The system is an all-fiber one where the maximum pulse energy achieved at 100 kHz repetition rate is 0.6 mJ and minimum pulse duration is ~30 ns at this energy level. Due to multi-stage architecture and special precautions, the system works without a high amplified spontaneous emission (ASE) level and shows an optical efficiency of 76%. After development of the laser amplifier, and certification of its materials processing capability, an industrial prototype was configured by taking the cost-efficiency into account . The laser components were placed into a compact case which has a simple design for thermal cooling. The developed industrial laser amplifier prototype has several unique properties with respect to other equivalent MOPA design fiber lasers. In material processing, high stability and high beam quality lead to high consistency. Reduced diameters of active and passive fiber cores and specially optimized fiber splices, which are used in the system architecture, result with higher beam quality thus the focusing is superior to many contemporary commercial lasers. As the intensity (areal power density) is the physical quantity that drives the nature of interaction of laser output with materials, the developed system offers long operation life-time due to its capability of operation at lower power levels than its contemporaries. In order to demonstrate the efficiency and the ability of processing various different kinds of materials with the developed laser amplifier system, a multitude of processing applications such as micro drilling, solar cell edge isolation, deep engraving and color marking were tested on metal, semiconductor and insulator surfaces and the results are discussing in relationship with various system operation parameters.

Suggestions

Investigation of Electromagnetic Energy Harvesting by Using Fractal Antenna
Ozdemir, Huriye; Nesimoglu, Tayfun (2017-06-24)
Microwave energy harvesting has the potential to power low powered electronic micro systems. Here we propose a fractal antenna topology that may be used for the conversion of microwave energy into usable DC power. The design of a broadband antenna that uses fractal approach is investigated. Simulation results demonstrate that improvements may be obtained in bandwidth and gain characteristics of planar antennas by using fractal approach.
Development of a picosecond pulsed mode-locked fiber laser
Yağcı, Mahmut Emre; Altan, Hakan; Department of Physics (2013)
Fiber lasers represent the state-of-the-art in laser technology and hold great promise for a wide range of applications because they have a minimum of exposed optical interfaces, very high efficiency, and are capable of exceptional beam quality. In the near future, the most important markets such as micromachining, automotive, biomedical and military applications will begin to use this technology. The scope of this thesis is to design and develop a short picosecond pulsed fiber laser using rare-earth doped ...
Development of strain monitoring system for glass fiber reinforced composites via embedded electrically conductive pathways
Tanabi, Hamed; Erdal Erdoğmuş, Merve (Informa UK Limited, 2019-06-15)
Among numerous types of health-monitoring and damage-sensing sensors that can be integrated into composites, electrically conductive sensors offer a simple, cost-effective, and durable option for structural health monitoring in fiber reinforced composites. In this study, a novel approach is introduced to create electrical conductive networks in glass fiber reinforced composites. For this purpose, hollow micro-channels are generated using vaporization of sacrificial components (VaSCs) which are subsequently ...
Proposal of a Novel Gravity-Fed, Particle-Filled Solar Receiver
JOHNSON, Evan; Baker, Derek Keıth; Tarı, İlker (2016-10-14)
Solar Thermal Electricity power plants utilizing solid particles as heat transfer and storage media have been proposed by several research groups, with studies citing benefits of increased thermal efficiency and lower cost. Several types of solid particle receivers have been proposed, with leading designs consisting of particles falling or suspended in air. A new solid particle receiver is proposed here, consisting of a receiver fully packed with particles flowing downward with gravity. Particle flow rate i...
Improved grating based temperature measurements using deconvolution of optical spectra
Ergul, FR; Ertekin, T (2000-11-06)
The basic concepts of temperature measurement in power transformers and underground power cables using fiber optic gratings are introduced. The economic benefits of continuous temperature measurements are discussed. The problems encountered in high density applications, i.e. using many sensors in the same power transformer, is identified as the resolution limitation due to comparatively large bandwidth of optical filters used. The deconvolution technique has been proposed as a possible solution to improve a...
Citation Formats
Y. O. Aydın, “Development of a 60 w pulsed fiber laser amplifier for materials processing,” M.S. - Master of Science, Middle East Technical University, 2014.