The foundation of the Institute of Photonics and Electronics (IPE), Academy of Sciences of the Czech Republic, was closely connected with changes in the organisation of science in Czechoslovakia made by the Government in 1952, when the Czechoslovak Academy of Sciences (CAS) was founded. Preparation steps for the foundation of the Institute, that time under the name of the Institute Theoretical Radio Engineering (ITRE), CAS, were made in 1953 by a small group headed by Sergej Djaďkov, one of the leading personalities of the Czechoslovak industrial research in electronics.
A pertinent decision of the Presidium of the CAS was made on 1 October, 1954 and that day is taken as the official date of the ITRE and also of the IPE foundation. The real work started on January 1, 1955 and in the same year, the ITRE was re-named to the Institute of Radio Engineering and Electronics of the CAS. This was the name of the Institute in a long period of the years 1955 - 2006. Sergej Djaďkov was appointed the first Director of the Institute. A small group of experts from industrial research of stable oscillators and precise frequency and those active in applications of random processes and statistical methods in radio engineering came with Djad´kov to the Institute. Moreover, a number of individual experts joined the Institute and formed research teams in the fields of circuit theory, precise measurements of time intervals and electromagnetic wave propagation. The Institute attracted world's attention by successfully evaluating the Doppler Effect during the flight of the first satellite orbiting the Earth, Sputnik, in 1957. On the 1958 EXPO world exhibition in Brussels two of the Institute’s achievements – a fully automatic computer based on the probability principle and an apparatus for the resonance transformation of signals – were awarded gold medals.
At the end of 1955, there were 36 co-workers (including 16 researchers) in the Institute, one year later, the corresponding numbers were 71 (19) and in 1960 even 180 (30). In 1959, a group of researchers specialized in random processes left the Institute and joined the newly established Institute of Information Theory and Automation of the CAS.
In the first years of its activity the Institute was dislocated at 14 different places over Prague. A new Institute´s seat in Kobylisy was finished and opened only in 1961, which was a very important step for the development of its experimental research facilities. For example, the first etalon for precise time and frequency measurements with a stable crystal oscillator thus could be placed in a 14-meter deep and temperature-controlled well constructed in the building.
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Better experimental facilities and experience of research teams of the Institute created necessary conditions for achieving important results in several research areas. Jiří Tolman, a leading personality in the research of standard time and frequency, encouraged several co-workers to pursue research in quantum electronics with the aim of developing a maser system. The start of operation of the ammonia maser on 26 March 1963 (the first maser in Czechoslovakia, and only the sixth in the world) was a breakthrough in the fields of quantum electronics and laser physics in our country. Shortly after, the ruby laser followed, constructed by Jan Blabla in May 1963, only three years after the famous laser invention by Theodor Maiman. Jan Blabla and his colleagues were also successful in the construction of helium-neon (June 1964), high-power carbon dioxide (1966), nitrogen (1966) and helium-cadmium (1970) gas lasers.
In the beginning of 1963, a new Director of the Institute, Václav Zima, was appointed. He made substantial changes in the Institute’s scientific program and its structure. The Department of Electromagnetic Wave Propagation was transferred to the Institute of Geophysics, CAS and, on the contrary, part of the former Laboratory of Optics of the CAS, engaged in the research of optical materials for the infrared spectral region, was included into the Institute. And later on, in 1965, one department of the Institute of Physics of the CAS, dealing with the research of ferroelectric single crystals and their electronic applications, was transferred to the Institute, where a new Department of Non-linear Dielectrics was set-up.
The above mentioned changes in the Institute’s scientific program reflected the world progress in the field of microelectronics, optoelectronics and quantum electronics. In order to stimulate these processes, a considerable part of the Institute’s capacity was focused on the research oriented towards semiconductor technology, optical communications and physics. Selected research activities that were pursued after 1965 and which formed the future development of the Institute are summarized below.
Circuit theory has been the field of research in the Institute since its establishment. At the beginning the research was devoted to the theory of chains of two-ports, to electrical filter theory and to the theory of non-linear circuits and oscillations. Later on the research was concentrated on discrete and digital signal processing, especially on digital filters, discrete Fourier transform, and spectral and cepstral analysis. In 1981, a small research group started to study the speech analysis, speech coding and speech synthesis. From the very beginning it cooperated with the Institute of Czech Language, the Institute of Information Theory and Automation of the Academy and with several industrial institutes. In 1987 the cooperating research teams were awarded the Czechoslovak Academy of Sciences Prize for their contribution to speech coding.
The efforts in standard time and frequency provided worldwide recognized results, for example, a method for accurate time comparison using television synchronizing pulses. In the pre-GPS era, this method, devised by Jiří Tolman, was used all over the world.
Another outstanding researcher, Věnceslav František Kroupa, cooperated initially with Jiří Tolman on the building-up of the Czechoslovak centre of standard frequencies. Later on he pursued his work in the group around Václav Zima, contributing significantly to the study of frequency synthesis and receiving international recognition. His book “Frequency Synthesis: Fundamentals and Measurements“, published in 1973, was the first book in the world written about this field. In recognition of his contribution, he was awarded the Mach Medal of the Academy of Sciences in 2003.
Optoelectronics has been developing since the mid-sixties. The Institute’s activities in this area began with the investigation into diffused GaAs-based radiation sources. The Institute was one of the few institutions in the world at that time investigating, designing and manufacturing GaAs electroluminescent numerical displays. The original display design, in the context with the emerging digital techniques, generated considerable interest abroad.
The investigation of physical principles of electroluminescent elements was pursued from 1967 to the end of 1980s. The Vapour phase heteroepitaxy of GaP was employed to manufacture GaP substrates for electroluminescent diodes in the red region of the optical spectrum. This technology was further improved by the employment of liquid phase epitaxy for the preparation of heterostructures. In 1979, the attention was shifted to semiconductor light sources for optical communications. The activities were concentrated on two directions: The first one was based on the AlGaAs /GaAs system for 0.8-μm window, and the second one on the InGaAs/InP system for operation in the 1.3- and 1.55-μm windows. In 1981, continuous light emission at 0.8 μm was achieved at room temperature with an AlGaAs/GaAs laser. In 1988, continuous operation was achieved with a laser for the 1.3-μm window, and a year later, with a laser for the 1.55-μm window.
A novel diagnostic technique, Secondary Ions Mass Spectroscopy (SIMS), was implemented in 1974 and proved to be very useful for explaining the mechanisms of ionization of atoms emitted from the surface of solids. The contributions of Zdeněk Šroubek to understanding charge transfer processes at surfaces have received international recognition, ever since. Other analytical methods suitable for electrical and optical studies of optoelectronic structures have also been systematically developed and employed. Among them, the most notable are Deep-Level Transient Spectroscopy (DLTS) and Low-temperature Photoluminescence (PL) spectroscopy.
In the field of coherent optics, the equipment and the experience gained in holographic recording were directed to the development of several special methods of holographic interferometry for the investigation of deformations and mechanical vibrations of various objects or revealing their shapes by holographic topography. Holographic diffractive gratings as an advantageous alternative to the gratings ruled mechanically were produced and supplied to industry for special optical devices. Original contributions to the theory of holographic imaging were made; the idea of focusing coupling gratings in planar waveguides represented the world priority.
In 1977, the development of integrated optics, i.e., the research of various waveguide elements for dividing, combining, controlling and processing optical signals directly at optical frequencies, started. Theoretical analysis of light propagation in planar and channel waveguides has been developed, particularly with respect to anisotropy of the substrate and to electrooptical and acoustooptical interactions. Methods for the design as well as preparation of lithographic masks were worked out to facilitate the experimental work.
At the end of 1970s, in agreement with world trends in optical communications, several teams in the Institute started to deal with the preparation and characterisation of optical fibres. At the end of 1980s, joined effort of our Institute and the Institute of Chemistry of Glass and Ceramic Materials of the CAS resulted into methodological and technical support of technologies for optical communications in Czechoslovakia. This support included for example, physical models used for the control of preparation of graded-index fibres, unique devices for the measurement of the fibre diameter during drawing and for automatic control of this process. These results were supported by extensive theoretical and experimental research on light propagation in fibres for both communications and sensors, fibre characterization, and technology of fibre components. Emphasis was also given to the research on polarization-maintaining fibres with stress-applying parts.
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The political changes in 1989 and the later division of Czechoslovakia had great impact on the CAS and its Institutes. A pertinent document proving the existence of the Institute within the Academy of Sciences of the Czech Republic (ASCR) and signed by the President of the ASCR became effective on December 31, 1992. Of course, the research work went on since November 1989 all the time without any interruption. As early as in 1990, just at the beginning of the new era, an Institute’s Scientific Council was elected as a body with an active share on managing the Institute and Viktor Trkal was appointed Director. Gradually, some changes in the research program arose – the emphasis was shifted back to basic research with the aim of achieving standards common in technologically advanced countries. The applied research was suppressed, also due to the collapse of the Czechoslovak electronics industry.
Through the first all-Academy evaluation process in 1992 the Institute passed with rather favourable results. Despite of the fact that the scientific programme was, in essence, approved, the number of employees was reduced by one third, which resulted in staff of 128 employees, including 68 researchers. Since then, the evaluations of the Institutes of the ASCR are being performed regularly on international level. Jan Šimša was appointed as the Director of the Institute in 1994, and after two terms in this position, he was succeeded by Vlastimil Matějec in 2002.
Since 1990 the research of the Institute has been concentrated on three research areas - signals and systems, photonics, and materials research for optoelectronics. Importance of the research in the fields of photonics and optoelectronics is reflected also in the Institute's name, since 1st January 2007 it is the Institute of Photonics and Electronics, AS CR, v.v.i (v.v.i - veřejná výzkumná instituce, english translation: public research institution). Recent research achievements are described here. Here are mentioned only activities which have emerged or have been developed with special momentum after 1990.
Several diagnostic techniques have been developed for the state-of-the-art characterization of semiconductor bulks, layers, structures and surfaces as well as glass materials. The capability of the DLTS spectroscopy has been enhanced considerably by a recent introduction of advanced equipment. The DLTS has been further extended by the development of admittance spectroscopy. Temperature dependent Hall effect measurements of semi-insulating materials are pursued in the range 7 K – 430 K on the built equipment with the closed cycle He-refrigeration system. Low-temperature PL spectrometer now enables us to make sensitive measurements with high resolution in a spectral range 300-5000 nm. The characterization capability has been further improved by a scanning electron microscope equipped with EDX system and recently extended by a home-made cathode-luminescence. The time-of-flight mass spectrometer has been developed to enhance the performance of the SIMS apparatus. Nanostructures and very thin layers of selected semiconductors are being studied by ballistic electron emission microscopy and spectroscopy, and also by a scanning tunneling microscope developed in the Institute.
Meta-stable states of DX centers were studied experimentally in cooperation with University of Manchester Institute of Science and Technology (UMIST), England. It was found that Sn-related DX center in AlGaAs exhibited considerably different dynamic properties from those of Si- and Te-related centers. A new mechanism of degradation during operation of commercial high-brightness GaP:N green light emitting diodes has been found by DLTS and electroluminescence spectroscopy. This research was done in co-operation with Siemens, Germany.
The self-consistent Green's function technique, within the framework of the tight-binding approach, has been developed and tested, which allows realistic calculations of the electronic structure of strongly localized defects in III-V compounds to be made. The technique has been used for the analysis of localized modes associated with defects in photonic crystals in co-operation with the University of California, Irvine, and Lisbon University. Theoretical research of photonic crystals is being concentrated on random active media, analysis of scattering properties of cylindrical left-handed materials, and on non-linear effects.
In 1993, the Laboratory of Technology of Optical Fibres, a part of the former Institute of Chemistry of Glass and Ceramic Materials joined the Institute. This act made it possible to strengthen the Institute research in the field of optical fibres, because the Laboratory´s program has been focused on material research of optical fibres for communications and chemical sensing. Physicochemical principles of the fabrication of multilayered optical structures via the chemical vapor deposition and sol-gel methods have been investigated. On this basis, rare-earth doped active fibres and novel types of sensing fibres, such as sectorial fibres, inverted-graded index fibres, fibres based on soft optical glasses, have been prepared and investigated in collaboration with researchers at the Ecole Central de Lyon, France, and the University of Jean Monnet in Saint Etienne, France. Special polymeric and xerogel coatings sensitive to chemicals have also been investigated. Recently, microstructure fibres and special fibres with long-period gratings have been prepared in the Laboratory.
Advanced fibres produced by the Laboratory represented, to a great extent, a basis for the investigation of non-linear fibre optics. The research into generation, amplification and non-linear propagation of ultrashort optical pulses in active fibres was carried out. Novel methods for preparing twin-core fibres were designed, the fibres were prepared and tested. Software tools for the analysis and design of erbium-doped, erbium-ytterbium-doped praseodymium-doped and Raman fibre amplifiers have been developed. These programs have been used for the optimization of rare-earth-doped fibres and for the analysis of transient effects in fibre amplifiers. They have also been integrated into commercial simulation packages by Optiwave Inc. (Canada).
Research into surface plasmon resonance (SPR) sensors started in the early 1990s. Initially, the research effort was mainly focused on theoretical study of surface plasmons and their experimental investigation by the attenuated total reflection method. The first SPR sensor developed at the Institute in 1992 was based on the attenuated total reflection method and angular scanning. Shortly afterwards, a fibre optic SPR sensor has been proposed. The concept of the optical fibre sensor has been further refined over the following years and resulted in a smallest SPR fibre optic sensor developed worldwide. SPR sensors based on integrated optical waveguides have also been investigated and laboratory prototypes of integrated optical SPR sensors based on ion-exchanged waveguides and spectral modulation have been demonstrated. In the late 1990s, the surface plasmon resonance phenomenon on diffraction gratings has been studied. Based on this research, a new research program aimed at multichannel SPR sensors using diffraction gratings has been initiated. In 2002, this program resulted in a unique multichannel SPR sensor based on spectroscopy of surface plasmons on an array of diffraction gratings, the first SPR sensor platform capable of performing over 100 measurements simultaneously. In collaboration with scientists at the Institute of Macromolecular Chemistry, Prague, and the University of Washington, Seattle (USA), Institute researchers exploited the unique SPR sensor platforms for the detection and identification of chemical and biological analytes relevant to environmental protection (pesticides), medical diagnostics (hormones, antibodies), food safety and security (chemical contaminants, toxins, bacteria). SPR sensors developed at IPE have provided a tool enabling research in biomolecules and their interactions carried out in collaboration with the Institute of Haematology and Blood Transfusion, Prague.
Directors of the Institute:
1954 - 1963: Sergej Djaďkov
1963 - 1989: Václav Zima
1990 - 1994: Viktor Trkal
1994 - 2002: Jan Šimša
2002 - 2012: Vlastimil Matějec
2012 - dnes: Jiří Homola
Documents relevant to the history of the IPE:
