The satellite market is shifting towards smaller (micro and nanosatellites), lowered mass and increased performance platforms. Nanosatellites and picosatellites have been used for a number of new, innovative and unique payloads and missions. This trend requires new concepts for a reduced size, a better performance/weight ratio and a reduction of onboard power consumption. In this context, disruptive technologies, such as laser-optical communication systems, are opening new possibilities. This paper presents the C3PO<sup>1</sup> system, “advanced Concept for laser uplink/ downlink CommuniCation with sPace Objects”, and the first results of the development of its key technologies. This project targets the design of a communications system that uses a ground-based laser to illuminate a satellite, and a Modulating Retro-Reflector (MRR) to return a beam of light modulated by data to the ground. This enables a downlink, without a laser source on the satellite. This architecture suits well to small satellite applications so as high data rates are potentially provided with very low board mass. C3PO project aims to achieve data rates of 1Gbit/s between LEO satellites and Earth with a communication payload mass of less than 1kilogram. In this paper, results of the initial experiments and demonstration of the key technologies will be shown.
The paper presents concept, summary of numerical modeling and technology chain proposition for fabrication of measurement heads of integrated grating interferometer and interferometric tomograph. In both cases, the measurement head is a monolithic PMMA cuboidal block with diffraction grating integrated. The structures replace a set of bulk optical elements used in classical interferometric setups. Fabrication of the measurement heads by replication is the crucial aspect of significant reduction of proposed system manufacturing. Numerical treatment performed in geometrical and scalar-wave regime, covers investigation of external as well as internal properties of the measurement heads. Modeling was also the basis for determination of acceptable measurement head replicas quality providing beam propagation proper for both considered interferometric techniques. The technology chain proposed in the paper covers master fabrication and its replication steps leading to fabrication of truly low-cost measurement devices.
In the paper, we present design, numerical modeling and measurement results of silicon X-Y movable platform
dedicated for miniaturized microinterferometric sensor based on grating interferometry. The structure fabricated
with double-side DRIE of SOI wafer, provides independent movement in x and y directions in the distance of
±35 <i>μm</i> with driving voltage upto 150 <i>V</i> . The presented microstructure has 160 <i>nm</i> deep diffraction grating
integrated on its surface. Small, static movement of the structure, with nanometric resolution, in direction
perpendicular to the grating lines, provides phase shifting of two conjugated interfering beams. Optimization
of the structure driving in order to achieve maximum movement resolution is covered in details. The in-plane
displacements of the structure is characterized with common correlation method that needs no markers imprinted
on its surface. Resolution of the method depends on the microscopic imaging system. The performance of the
method is presented on the example of various steering modes of the platform, covering parabolic and linear
In this paper we present the silicon comb-drive X-Y microstage with the frame-in-the-frame architecture intended to be
monolithically integrated with a glass microlens as a MOEMS 2D scanner for the Miniaturized Confocal Microscope On-
Chip. The microstage is characterized by relatively large travel range (± 35 μm in X-direction and ± 28 μm in Y-direction at
100 V) for a small number of driving electrodes, without noticeable mechanical X-Y crosstalk. We describe the design,
ANSYS modeling, fabrication process and static characterization of the device.
The paper deals with design and implementation of an optical extensometer based on grating (moire) interferometry, for
large engineering construction monitoring. The paper presents the principles of the grating interferometry and the
construction of miniaturized and portable version of grating interferometer and its implementation for out-door
measurement directly at civil engineering structures. The paper presents also a concept of the low-cost full-field optical
In the paper idea of integrated waveguide micro-interferometric system is presented. Results of numerical simulation of beam propagation (geometrical and wave depiction) in the measurement interferometric module is presented. Article also briefly presents laboratory setups, which are used to model the interferometers.
Several versions of grating interferometers (GI) with conjugated wavefronts, specially adopted for in-plane displacement measurements of microelements or microregions at larger specimens, have been proposed including four-beam three mirror GI, Czarnek's interferometer or fiber optics based GI. Recently the grating interferometers based on the concept of guiding the light in a waveguide (block of glass) have been developed. Such design is especially useful to combine the measurement module with optical microscope. In the paper, we propose two versions of new compact, sensor-like optical microextensometers based on the waveguide grating interferometry. The microextensometers consist of the interferometer head integrated with illumination and detection modules, so that it can work without any microscope. The compact and portable design (using the wire-less CCD camera) enables to use it outside the laboratory, e.g. directly on the engineering objects under test. The two GI versions are devoted to: periodical measurements and constant monitoring of a reference (DOE) structure attached to an object. In the paper the concept and design of both sensors is presented together with selected numerical simulations of waveguide plate.
Recent growth of micro and nano technology offers large variety of micro scale devices, which gradually replace bulk appliances of everyday use. MEMS devices are being used in medical, science research, military and industrial applications. Since their technology is not fully mastered yet, they require special measurement treatment from stage of production to stage of utilization. Most of nowadays used bulk measurement instrumentation require special preparation of MEMS element to test (putting elements on special stages or combining MEMS devices with cheap and simple instrumentation (fiber sensors)). Since MEMS technology is meant to be inexpensive a trend of building MEMS measurement instrumentation for nano and micro elements testing appeared. In this paper we present the concept of novel multifunctional waveguide interferometer for three components of displacement vector measurement of elements with optical or rough surfaces. The measurement system combines the various techniques: conventional Twyman-Green (TGI), grating (moire)
interferometry (GI), ESPI and digital holographic interferometry (DHI). It consists of several modules such as light source and detector integrated module, passive interferometric module, waveguide interferometer head and MEMS based active beam manipulators. The proposed design of modules decrease significantly their sensitivity to vibration, so that they can work in instable environment.
A variety of microelements require enhanced tools for their testing at various stages of production and exploitation. It refers to their analysis at static, quasistatic and vibration modes. Especially active, vibrating elements introduce unprecedented requirements concerning their design and testing. In the paper we present methodology and system based on combined digital holographic interferometry (DHI) and time average digital holography (TADH) which enables quantitative analysis of static and slowly changing microelements as well as qualitative analysis of vibrating objects. In DHI due to usage of numerical phases calculated from a sequence of holograms, an arbitrary phase difference related to a chosen stage of varying object can be calculated. TADH provides information about the vibration mode shapes which is crucial for the further analysis of vibrating microelements. Exemplary quantitative results of PZT actuator and membrane out-of-plane deformation measurement and qualitative results of vibrating membrane testing are presented and discussed.
Fresnel and Fourier holograms recorded by CCD/CMOS cameras can be numerically or optoelectronically reconstructed in order to provide visualization of 3D objects or to enable further manipulation of their phases and amplitudes. In the paper we propose to introduce into digital holographic (DH) setup Liquid Crystal on Silicon (LCOS) spatial light modulator as an active 2D optoelectronic element which facilitates performing a variety of operations at the recording and reconstruction stages. This includes introducing phase shifting digital holography, additional phase manipulation for object contouring and displacement measurements as well as for optoelectronic reconstruction of all types of digital holograms. The results of initial experiments performed with LCOS are presented and discussed. Also the future directions of development of active DH and DHI system are outlined.
Stroboscopic interferometry is the most popular method for investigation of active, vibrating elements. The interferograms obtained in measurement steps may be analysed by temporal phase shifting method or by spatial carrier frequency methods. The first one requires sequential capturing of phase-shifted interferograms which complicates the measurement system and introduces high stability requirements for the setup. The spatial methods need a single interferogram with a proper spatial carrier frequency (SCF), so they are more suitable for dynamic events analysis. The most frequently used spatial method is based on Fourier transform of an interferogram with linear SCF and can be applied to analysis of restricted class of elements represented by quasi-linear fringes. This can be easily expanded by considering elements with circular carrier fringes (CCF). In the paper two approaches to analysis of interferograms with CCF, namely: coordinate transform Fourier transform technique and direct filtering Fourier transform technique are explained. The error analysis of both techniques applied for different classes of interferograms is presented. The methodology of CCF interferogram analysis based on FT methods applied for micromembranes is presented and several exemplary results are given.