Andrzej Grobelny

Analysis of pumping efficiency of side coupling method in double-clad fibers doped with rare earth ions

A method of pumping lasers built on the basis of double-clad neodymium-ion doped fibers is presented in the paper. Couplings were realized by asymmetrical couplers built with a multimode PCS (pumping) fiber and a double-clad (pumped) fiber. Special software for designing such asymmetrical couplers was elaborated. It allows us to choose appropriate parameters of the couplers components, enabling to obtain a maximum pumping power, introduced by the purpose-built coupler.

A numerical analysis of pumping efficiency using the side coupling method in double-clad fiber lasers

The numerical analysis of the efficiency of the side pumping method using special asymmetrical couplers for the high-power double-clad fiber lasers is presented in the paper.

Interference aspects of terahertz transmission

In this paper, interference aspects of terahertz transmission are considered. Possible interference effects in indoor THz communication are experimentally proved using a THz photomixer setup. The method of coherent homodyne detection is applied to explain the problem. Fourier Transform is used for precise analysis of the interference effects and calculations of the optical path changes. The paper explains the problem of multipath communications in the terahertz range.

Ray Tracing Method Applied for DC Fibers

In the paper the ray tracing method for analysis of Double-Clad (DC) fibers has been applied. The algorithm permits to determine attenuation, power density and absorption along a fiber. The most popular symmetrical, asymmetrical and D-shape fibers have been analyzed. The results show that the differences in pumping efficiency for the analyzed fibers are not significant.

THz optical mixer

Terahertz sources and characterisation of the THz radiation are briefly reviewed. Technique of the THz photomixing is described.

Frequency stabilized 633 nm diode laser

Construction of a simple single-frequency diode laser 632.8 nm, used as a frequency standard in the laser interferometers is demonstrated. Two different systems applied for frequency stabilization of diode laser were used . For diode laser used as the secondary standard, the system stabilizes diode temperature, the frequency stability of the laser reaches value 1 part in 106. For diode laser used as the primary standard is developed stabilization system using narrow absorption in iodine, the frequency stability of constructed diode laser reaches value 1 part in 1010 . The stabilization method can be used for another diode lasers with different wavelength using in fiber communications systems.

The pumping of double-clad neodymium fiber

The paper presents a new method of pumping lasers built on the basis of double-clad neodymium-ion doped lasers. The asymmetrical couplers were realized by grinding and built on a multi-mode PCS (pumping) fiber and a double-clad (pumped) fiber. Special software for designing such asymmetrical couplers was elaborated. It allows us to choose appropriate parameters of the couplers elements, enabling us to obtain a maximum pumping power, introduced by the purpose-built coupler.

Modelling of frequency stabilization of diode laser based on 3 rd , 5 th and 7 th harmonic method

The stabilization of diode lasers with a wider spectral line based on the iodine absorption cell, has been examined with a stabilization method of a 3^rd, 5^th and 7^th harmonic deviation. Possible stability levels, according to the width of diode lasers spectral line have been checked. The 3^rd, 5^th and 7^th harmonic deviation stability method have been compared.

Efficiency of active Double-Clad fiber pumping in different types of fibers

In the paper the pumping efficiency of active, different types double-clad fiber has been analyzed. The ray tracing method has been applied for fibers analysis. The most often utilized fibers: circular non-concentric, D-shape, fin-shape, rectangular fibers have been analyzed. The results show that the geometry of the inner clad fibers is not very significant for pumping efficiency, except the case of circular one.

Implementation of PSD sensor for measurement of vibrations

The presented in the paper optical method of measuring vibrations and oscillation has many benefits. They are: high measuring speed and high sensitivity of the method. Another benefit is the possibility of the non-contact measurement, when both laser and the gauge are both not mounted to the oscillating element. Changing the configuration of the optical system enables an increase in the resolution of the measurement. Furthermore, it is important to emphasize the ease of selecting the laser beampsilas course in many non-typical measuring conditions.