IPG Photonics

About: IPG Photonics is a based out in . It is known for research contribution in the topics: Laser & Fiber laser. The organization has 903 authors who have published 1241 publications receiving 63339 citations.

Sensitivity of a phase-sensitive optical time-domain reflectometer with a semiconductor laser source

Abstract: In the present paper we perform, for the first time, an analysis of the average sensitivity of a coherent phase-sensitive optical time-domain reflectometer (phase-OTDR) with a semiconductor laser source to external actions. The sensitivity of this OTDR can be defined in a conventional manner via average SNR at its output, which in turn is defined by the average useful signal power and the average intensity noise power in the OTDR spatial channels in the bandwidth defined by the OTDR sampling frequency. The average intensity noise power is considered in detail in a previous paper. In the current paper we examine the average useful signal power at the output of a phase-OTDR. The analysis of the average useful signal power of a phase-OTDR is based on the study of a fiber scattered-light interferometer (FSLI) which is treated as a constituent part of a phase- OTDR. In the analysis, one of the conventional phase-OTDR schemes with a rectangular dual-pulse probe signal is considered. The FSLI which corresponds to this OTDR scheme has two scattering fiber segments with additional time delay, introduced between backscattered fields. The average useful signal power and the resulting average SNR at the output of this FSLI are determined by the degree of coherence of the semiconductor laser source, the length of the scattering fiber segments, and by the additional time delay between the scattering fiber segments. The average useful signal power characteristic of the corresponding phase-OTDR is determined by analogous parameters: the source coherence, the time durations of the parts constituting the dual-pulse, and the time interval which separates these parts. In the paper an expression for the average useful signal power of a phase-OTDR is theoretically derived and experimentally verified. Based on the found average useful signal power of a phase-OTDR and the average intensity noise power, derived in the previous paper, the average SNR of a phase-OTDR is defined. Setting the average signal SNR to 1, at a defined spectral band the minimum detectable external action amplitude for our particular phase-OTDR setup is determined. We also derive a simple relation for the average useful signal power and the average SNR which results when making the assumption that the laser source coherence is high. The results of the paper can serve as the basis for further development of the concept of phase-OTDR sensitivity.

IPG fibre lasers and aluminium welding applications

Abstract: IPG Photonics was founded in Russia in 1990 by Dr Valentin Gapontsev. Initially, the company developed optical communication amplifiers and experienced very rapid growth as the global IT industry expanded. With the collapse of the IT bubble in the USA in 2000, however, the company’s results suffered and consequentially it undertook the development of a high-power fibre laser with the aim of moving away from reliance on the IT market, succeeding in moving into the area of materials processing. The development of a high-power fibre laser that could be used in the field of materials processing was substantially advanced by IPG Photonics in the 3 years from 2000 to 2003, by which time a laser with a worksite power of 4 kW (working head power loss ,3%) had been developed. This the extremely compact footprint of 0.8mm £ 0.85m. The appearance is shown in Figure 1. A 30 kW fibre laser was supplied to Germany and a 20 kW fibre laser to Japan in 2008. It is far easier to increase the power of fibre lasers than that of other solid lasers and CO2 lasers and currently they are capable of being increased to 100 kW. There has been no other example in the history of lasers in which such a combination of high power and high beam quality has been achieved in such a short time. Below is a description of the characteristics and capabilities of the IPG fibre laser, the advantages of its high power and high beam quality, and its applications.

High power ultra-compact, lightweight multi-kilowatt fiber laser system based on coherent&spectral beam combining

Abstract: A high power fiber laser system consisting of multiple fiber amplifier or laser systems amplifying the input signal in parallel is configured with a high power splitter such as to share some of the gain stages. The high power splitting component consists of high power fiber couplers and splitter(s). The splitter is a holographic optical element, a dielectric coated plate, a diffraction grating, or a volume Bragg grating. The resultant fiber laser configuration reduces the total number of amplifying stages including optical isolators and active fiber assemblies for the system and thus reduces the total volume and weight.

Below-bandgap photoreflection spectroscopy of semiconductor laser structures

Abstract: A new method of modulated light reflection ? below-bandgap photoreflection, is considered. Unlike the conventional photoreflection method, the proposed method uses optical pumping by photons of energy smaller than the bandgap of any layer of a semiconductor structure under study. Such pumping allows one to obtain the modulated reflection spectrum for all layers of the structure without excitation of photoluminescence. This method is especially promising for the study of wide-gap semiconductors. The results of the study of semiconductor structures used in modern high-power multimode semiconductor lasers are presented.

High-efficient kW-level single-mode ytterbium fiber lasers in all-fiber format with diffraction-limited beam at wavelengths in 1000-1030 nm spectral range

Abstract: The kW-level single-mode Yb fiber lasers at wavelengths in 1000 -1030nm spectral range with diffraction-limited beam and with direct diode pumping are remarkable high brightness and low quantum defect sources for tandem pumping of multi-kilowatt fiber and crystal laser systems. In this paper we present SM Yb fiber lasers in all-fiber format with powers 0.75kW, 0.90kW, 1.33kW and 1.40kW at 1007nm, 1010nm, 1018nm and 1030nm respectively with M2 values of output beams < 1.1. These are the highest powers of single mode CW Yb fiber lasers at wavelengths near 1 micron to the best of our knowledge. The fiber oscillators with direct diode pumping are highly efficient and have optical slope efficiencies from 64% at 1007nm to 78% at 1018nm relative to total laser diode pump power. The fiber lasers have 3-5m output delivery cable terminated with a LC-8 connector in dependence on power level and MFD of output fiber. The pump and non-linear process (SRS and MI) limitations are discussed.