摘要:
Methods and systems for transmission and reception of ternary phase-shift keyed data that include mapping triplets of binary bits to pairs of ternary symbols, such that three bits of data are encoded across two symbols having three-point constellations; modulating the pairs of ternary symbols onto a carrier; and transmitting the modulated carrier across a transmission medium.
摘要:
An inventive method for multi-symbol polarization switching for differential detection optical systems includes modulating a laser source by a DQPSK modulator, driving the DQPSK modulator with a data block configured for generating multi-symbol polarization-switched DQPSK differential-encoded signals, and polarizing the multi-symbol polarization-switched DQPSK signals with a polarizing modulator whose modulation speed is based on how often polarization states vary, wherein the data block provides a bits manipulation to provide the multi-symbol polarization switching thereby enabling differential detection for recovering correct original data by a receiver.
摘要:
A method for optical chirp-free optical polarization modulation includes dividing a data modulated optical signal into a first optical path and a second optical path, using a Mach-Zehnder intensity modulator in the first optical path for imparting a π phase difference between adjacent symbols of the data modulated optical signal in the first optical path, adjusting a delay and amplitude of symbols of the data modulated optical signal in the second path so that the symbols in the first path and the symbols in the second path are synchronized and have substantially equal power levels, and combining the first and second optical paths so that symbols from the first and second optical paths are in orthogonal polarizations.
摘要:
An inventive method for coherent interleaved polarization-multiplexing PolMux optical communications with a single IQ modulator includes modulating a light source to generate a 50% return-to-zero RZ signal pulse at a frequency Rs, driving a single IQ modulator with inphase I and quadrature phase Q data at a bit rate of sais Rs to introduce phase modulation on said 50% RZ signal pulse to produce a QPSK pulse signal with all symbols being in a same polarization state without any time overlapping; and polarization modulating said QPSK signal to alternatively convert said QPSK signal into two orthogonal polarizations states enabling an interleaving PolMux signal with a symbol rate of Rs/2.
摘要:
An inventive method for multi-symbol polarization switching for differential detection optical systems includes modulating a laser source by a DQPSK modulator, driving the DQPSK modulator with a data block configured for generating multi-symbol polarization-switched DQPSK differential-encoded signals, and polarizing the multi-symbol polarization-switched DQPSK signals with a polarizing modulator whose modulation speed is based on how often polarization states vary, wherein the data block provides a bits manipulation to provide the multi-symbol polarization switching thereby enabling differential detection for recovering correct original data by a receiver.
摘要:
A method for optical chirp-free optical polarization modulation includes dividing a data modulated optical signal into a first optical path and a second optical path, using a Mach-Zehnder intensity modulator in the first optical path for imparting a π phase difference between adjacent symbols of the data modulated optical signal in the first optical path, adjusting a delay and amplitude of symbols of the data modulated optical signal in the second path so that the symbols in the first path and the symbols in the second path are synchronized and have substantially equal power levels, and combining the first and second optical paths so that symbols from the first and second optical paths are in orthogonal polarizations.
摘要:
Optical surge preventing systems and methods for rare earth-doped optical fiber amplifiers are disclosed. The systems are so arranged as to cause any signal existing in a doped fiber section so as not to over excite the rare earth elements in the doped fiber section. In one embodiment, a background signal light with such a wavelength as to cause induced emission in the doped fiber section is always coupled into the doped fiber section regardless of whether a message signal light exists or not. The background signal light may be generated by any suitable light source or a light spontaneously emitted from either end of the doped fiber section. In another embodiment, a dummy signal light is coupled into the doped fiber section if the level of the message signal light becomes less than a predetermined value. Coupling of the background signal light or the dummy signal light into the doped fiber section may be done from either of the message signal input and output sides.
摘要:
A face data registration apparatus is an apparatus to register dictionary data for walker authentication by use of a face image. The face data registration apparatus causes a posture data collection unit to collect posture variation data from a plurality of face images obtained by photographing a face of a registrant whose posture (face direction) is changed, further causes a walking data collection unit to collect walking data from a face image obtained by photographing a face of the registrant who actually walks along a passage, causes a synthesizing unit to create dictionary data by synthesizing posture variation data and walking data and registers the created dictionary data as dictionary data used to authenticate a person who walks in the passage by face collation into a dictionary data unit.
摘要:
The present invention provides a Ni-based single crystal superalloy which has the following composition by weight: 0.1 wt % or more and 9.9 wt % or less of Co, 5.1 wt % or more and 10.0 wt % or less of Cr, 1.0 wt % or more and 4.0 wt % or less of Mo, 8.1 wt % or more and 11.0 wt % or less of W, 4.0 wt % or more and 9.0 wt % or less of Ta, 5.2 wt % or more and 7.0 wt % or less of Al, 0.1 wt % or more and 2.0 wt % or less of Ti, 0.05 wt % or more and 0.3 wt % or less of Hf, 1.0 wt % or less of Nb and less than 3.0 wt % of Re with the remainder including Ni and unavoidable impurities. This Ni-based single crystal superalloy has a low Re content and also has excellent high-temperature strength, mainly creep strength.
摘要:
A face data registration apparatus is an apparatus to register dictionary data for walker authentication by use of a face image. The face data registration apparatus causes a posture data collection unit to collect posture variation data from a plurality of face images obtained by photographing a face of a registrant whose posture (face direction) is changed, further causes a walking data collection unit to collect walking data from a face image obtained by photographing a face of the registrant who actually walks along a passage, causes a synthesizing unit to create dictionary data by synthesizing posture variation data and walking data and registers the created dictionary data as dictionary data used to authenticate a person who walks in the passage by face collation into a dictionary data unit.