Grzegorz Budzyn

Passive Multimode Fibre Optic Structures

The paper presents possibilities to use multimode network structures in commercial applications

Realization of the stream comparison mechanism in a CSMA/CD type multimode passive optical network node — experiments

In this paper we show and describe the experimental results obtained in the symmetrical, multimode passive optical network with the use of network nodes described in details in [1]. We prove that it is feasible to construct a simple and efficient passive optical network working with the use of CSMA/CD mechanism and that it is possible to construct such a network from a standard, easy to buy components. In the designed and tested network 850 nm VCSEL transceivers were used.

Influence of a laser beam's frequency stability on dislocation of vortex points in an optical vortex interferometer

New applications for optical vortex interferometers (OVIs) are under investigation. The precision of the OVI depends strongly on the accuracy of positioning of the vortex points, which requires more than one interferogram (fringe pattern), so the influence of the laser beams frequency stability is important. We present an analysis of the influence of the laser beams frequency stabilization on the accuracy of methods locating vortex points relative to dimensions in optical arrangements of OVIs.

Zeeman laser for straightness measurements

In the paper we present the prototype of a straightness measuring device that uses a frequency stabilized Zeeman He-Ne laser. The He-Ne laser line is split by Zeeman effect into two circularly polarized laser beams. The frequency of the radiations differ of 1,2 MHz. The surface stabilized ferroelectric liquid crystal cell is used to stabilize the laser frequency. As the result of the laser frequency stabilization the power of both radiation is equal. The circular polarizations of two laser beams are converted into two linear polarizations perpendicular to each other. The two laser beams pass close to the measured axis. Along the axis the analyzing probe is moved. The analyzing probe changes the ratio of the power of the horizontal to the vertical polarization. This ratio is analyzed by the receiver composed of the ferroelectric liquid crystal switcher, the polarizer and the detector. The straightness of 2 m long optical bench was measured with this techniques. The resolution of 0,1 μm and the accuracy of 0.5 μm were obtained. The accuracy of presented technique is not so good as in the methods using laser interferometer but is comparable with methods using PSD, quadrant detectors or CCD at the same time offering bigger resolution.

Determination of Possibilities of SI Plastic Fiber Application in Passive Optical Network

The main objectives of this paper is to improve knowledge of multimode fiber transmission over step-index plastic optical fiber SI POF with 1000 Lim core. The thick SI POF fibers seem a very attractive alternative in local computer networks for the “classic” (thin) single- and multimode fibers because of their low price and easy installation. In the paper we show measurements of bandwidth and attenuation of various SI POF optical paths. In particular, there was investigated a cascade of passive components (couplers, patchcords) which can be part of transparent (passive) optical networks.

A universal laser interferometer for high linearity measurements

In the paper we present the idea and measurement results of a modified laser interferometer with improved measurement linearity and measurement resolution. Presented solutions allow for linearity increase below 1nm mark with measurement resolution even of single picometers (depending on the noise parameters of the laser source and detection electronics) in the basic heterodyne configuration of the optical elements.

Two-dimensional sinusoidal signal quality improvement by combined software and hardware means

This article describes a two-dimensional, quadrature, sinusoidal type signal correction. Such signals are widely popular e.g. in motor control, laser interferometry and sensors applications. It is proved that in some situations it is necessary to improve the quality of the signals in order to obtain the required parameters. We show that the optimum solution is a combination of hardware and software correction mechanisms. We report the signal improvement of a factor of more than a hundred. The proposed unique construction is also characterized by a very fast dynamic response in the range of single microseconds. This feature makes the circuit suitable for wide range of applications.

Methods of Building Ethernet-type Passive Optical Networks

This paper presents three methods of constructing Ethernet-type passive optical networks. A novel construction of the symmetric optical networks based on a transmissive star structure is presented. Collision detection method used in copper Ethernet networks, CSMA/CD, was slightly modified to accommodate the differences between the passive optical networks and copper network.

Comparison of Bandwidth and Bit Error Rate of Passive Multimode Networks

This paper presents a passive multimode optical network BER measurement system along with measurement results obtained using this system for chosen passive network structures. The results of BER measurements were also compared with results of bandwidth measurements for the corresponding structures.

Method of improving the frequency repeatability of the intensity stabilized HeNe laser

A method of improving the frequency repeatability of a two-mode helium–neon laser starting from different initial conditions has been developed. The approach is based on locking the laser when a certain number of laser modes is observed. In order to avoid ambiguity we propose to tie the initial number of laser modes to the value of the intermodal frequency. Experiments proved that with the suggested design it is possible to lock the laser on the desired mode regardless of the initial conditions. In the experiments the frequency repeatability of the laser was equal to its frequency stability.