摘要:
In an arrangement and a method for electrically controlling the intensity of non-polarized light, a polarizing beam splitter is acted upon by the light to be controlled via an input face such that the light is split into two polarized light bundles that are orthogonal with respect to each other. Provision is made that a first reflecting device is configured for the reflection of at least one of the polarized light bundles, so that both polarized light bundles run in parallel. At least one electro-optical element is provided in a path of the parallel running polarized light bundles. The polarization is changed as a function of the supplied control voltage. Also provided is a second reflecting device for reflecting the light bundles in the opposite direction. The light bundles pass through the at least one electro-optical element twice and are directed by the first reflecting device to the polarizing beam splitter, and the controlled light can be extracted from at least one output face of the polarizing beam splitter.
摘要:
An intensity-dependent light modulating device or method for providing same, involves light successively passing through a polarizer, a first phase retardation plate and a first light modulator. The light then strikes a mirror and from there on, it passes once again through the light modulator and the phase retardation plate in the opposite direction and then strikes an analyzer that is crossed relative to the polarizer. The light modulator and the phase retardation plate are respectively located in an electric field in which the indicatrices of the light modulator and the phase retardation plate are deflected, wherein the deflection of the indicatrix of the light modulator is intensity-dependent. Due to the passage of light through the phase retardation plate and the light modulator, an intensity-dependent rotation of the direction of polarization occurs in such a way that higher intensity light is filtered in the analyzer while lower intensity light is transmitted. For example, a telescope is directed at an intensive light source in front of a dark background. The telescope only filters the intensive light source while the background can be simultaneously observed during almost the entire transmission.
摘要:
An intensity-dependent light modulating device involves a light successively passing through a polarizer, a first phase retardation plate and a first light modulator. The light then strikes a mirror and passes one again through the light modulator and the phase retardation plate in the opposite direction. The light then strikes an analyzer that is crossed relative to the polarizer. The light modulator and the phase retardation plate are respectively located in an electric field in which the indicatrices of the light modulator and the phase retardation plate are deflected, the deflection of the indicatrix of the light modulator being intensity-dependent. Due to the passage of light through the phase retardation plate and the light modulator, an intensity-dependent rotation of the direction of polarization occurs in such a way that higher intensity light is filtered in the analyzer while lower intensity light is transmitted.
摘要:
A method and device for reducing the distortion of optical pulses caused by the polarization mode dispersion in optical communication systems is provided. When an optical pulse having any polarization is transmitted through an optical communication system, which is optically anisotropic, at least in sections, the optical pulse may become distorted due to the different velocities of the various polarization components. This distortion of the optical pulses may reduces the maximum transmission rate of the system. A method is provided for functioning in response to the detected transmission quality of the communication system where a polarization-controlling device for setting the polarization of the optical pulse is driven in such a way that the transmission quality is maximized. An optical communication system, including an optical transmission medium, involves a device for determining the transmission quality of the communication system, a regulating device, and a polarization-controlling device. The output signal from the device for determining the transmission quality of the communication system may be applied to the regulating device, which drives the polarization-controlling device to change the polarization of the optical pulses in such a way that the transmission quality is optimized.
摘要:
A device for generating, adding and subtracting digital sequences of optical pulses and a method for the secure transmission of information. An interferometer having at least one electro-optical switch or electro-optical modulator positioned in one of its branch sections is used so that binary optical pulse sequences may be added and/or subtracted in the context of an electro-optical device and a method for the secure transmission of information using optical signals.
摘要:
A method and a device are described to compensate for polarization mode dispersion in an optical transmission link(9, 9′) having polarization-dependent transmission characteristics, in particular in optical fibers and cables with not only statistical, but preferred birefringence. A compensation element (1, 1′, 1″), whose length is adjusted non-destructively using an interference device (2, 2′, 2″), in particular a pressure mechanism, is connected upstream or downstream from the transmission link (9, 9′). The polarization states PL and PS of the compensation element are mixed by the interference and thus the length of the compensation fiber is defined at which a propagation time difference between the partial waves of polarization states PL and PS is increased or decreased so that it compensates for the propagation time difference &tgr; within the transmission link (9, 9′).
摘要:
An intensity-dependent light modulating device and method involves light successively passing through a polarizer, a first phase retardation plate and a first light modulator. The light then strikes a mirror and then passes once again through the light modulator and the phase retardation plate in the opposite direction, and then strikes an analyzer that is crossed relative to the polarizer. The light modulator and the phase retardation plate are respectively located in an electric field in which the indicatrices of the light modulator and the phase retardation plate are deflected, wherein the deflection of the indicatrix of the light modulator is intensity-dependent. Due to the passage of light through the phase retardation plate and the light modulator, an intensity-dependent rotation of the direction of polarization occurs in such a way that higher intensity light is filtered in the analyzer while lower intensity light is transmitted.
摘要:
A liquid crystalline material having a lamellar structure can be used for phase modulation. A liquid crystal having arcuated or angular dimer molecules so that the molecules each include two central units, and the longitudinal axes of the two central units exhibit at least approximately oppositely directed inclination angles with respect to the layer normal z. By configuring the two central units of the dimer molecule in accordance with the present invention, the molecular index ellipsoid, which is essentially composed of the components of the two readily polarizable central units, may be positioned such that the optical axis is always situated in parallel to the layer normal z, making it possible to prevent the light, which propagates in a defined direction orthogonally to the layer normal through the liquid crystalline material, from undergoing a polarization modulation simultaneously with the phase modulation.
摘要:
WDM multi-channel systems for large distances having a number of intensifiers may cause an increase in intensifications, which lead to considerable differences in intensity, even given modest wavelength dependence, making spectral leveling maybe necessary. The light from the fiber is first spectrally into channels, and, thus locally separated, projected onto the surface of an optic limiter based on an OASLM (optical addressed, spatial light modulator), in which the intensive channels are overproportionally attenuated. The tension dependence of liquid crystal cells, derived from exposure, is used to level the WDM channels. Lastly, the channels are again imaged onto a point and coupled into another fiber. The invention is used in WDM multi-channel systems for large distances a number of intensifiers.
摘要:
An electro-optic material that is characterized by short reaction times when working with a low drive voltage. For that, the electro-optic material has a lamellar liquid crystal (10), which contains one or more components and into which chiral molecules (20), whose longitudinal axes (m) are longer than the longitudinal axes of the molecules (10) forming the lamellar liquid crystal, are introduced at a predefined concentration, so that the longitudinal axes (m) of the chiral molecules (20) are tilted, without an external electric field, statistically by a predefined angle (&thgr;m) toward the normal (z) of the layer of the lamellar liquid crystal (10).