2698results about "Distortion/dispersion elimination" patented technology

An optical data storage and retrieval system uses a flying head. The flying head is supported on a moving media having information stored in a plurality of stored data locations thereon. Information is stored in each of the plurality of media locations as physical structures capable of modulating the polarization state of incident light into one of two output polarization states. The flying head includes an optical processing assembly which directs an incident light beam having a source polarization state onto the moving media, accessing successive data locations. A reflected light beam having the source polarization state of the incident light beam modulated by a respective polarization modifying data location into one of the output polarization states is received by the flying head. The optical processing assembly optically transforms the modulated output polarization state of the reflected light beam into two return light beams having differentially modulated intensity related to the output polarization state of the reflected light beam. The two intensity modulated return light beams are optically coupled to a distal differential detector which outputs digital data representing the stored data information for the subject data location. A preferred embodiment includes optical fibers for coupling the incident and return light beams between the detector and the flying head. The optical assembly of a preferred embodiment includes an optical plate having pre-shaped and dimensioned recesses for automatically locating and aligning multiple optical components comprising the assembly. The flying head may also include a servo-controlled micro machined mirror for directing the incident and reflected light beams to and from the media.

A method is provided for an equalization strategy for compensating channel distortions in a dual-polarization optical transport system wherein the received signal includes a complex signal of a first transmitted polarization component and a complex signal of a second transmitted polarization component. In a first step, a blind self recovery mode used a blind adaptation algorithm in calculating and modifying multiple complex equalizer transfer function coefficients to enables recovery of only the complex signal of the first transmitted polarization component. In a second step, equalization is performed in a training mode for recovery of the complex signals of the first and second transmitted polarization components. In a third step, equalization is performed in a data directed mode. The method is suited for a digital signal processing implementation in a coherent receiver.

An illumination apparatus is used in the light communication system. The apparatus receives electricity from a commercial alternating-current power source and a light-emitting element in the apparatus emits light. The zero passage time of commercial alternating-current power source is detected and signals are transmitted from illumination apparatus, or intercommunications between terminals of communication equipment take place, during a specific reserved time that is in synchronization with this zero passage time.