 Holographic display element and method of making the same |
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| Multiple-resolution scanning device |
| The present invention is a multiple-resolution scanning device that changes paths of light to have ... |
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| Optical signal free-space conversion board |
| This is a board to transport and convert optical outgoing free-space signals from a spatial light ... |
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| Polyhedral integrated and free space optical interconnection |
| OF THE INVENTION FIG. 1 shows a prior art communications system using holographic optical elements.... |
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| Component for optical data transmission |
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| Image processing apparatus |
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| Process and recording media for continuous wave four-level, two-photon holography |
| We claim: 1. A recording medium for holography, said medium comprising a transparent resin ... |
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| Process for the preparation of aryldimethyl(3-aryl-propyl)silanes |
| I claim: 1. A process for the preparation of a compound of the formula I ##STR13## where X is CH.... |
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| Optical information storage on a bacteriorhodopsin - containing film |
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Optical signal processor, method of its control, method of its designing, and method of its production
| Details |
Inventors: Jinguji, Kaname; Kawachi, Masao; Takiguchi, Koichi;
Assignee: Nippon Telegraph and Telephone Corporation (Tokyo, JP)
Primary Examiner: Bovernick; Rodney B.
Assistant Examiner: Wise; Robert E.
Attorney, Agent or Firm: Spencer & Frank
An optical signal processor according to the present invention is an optical circuit of a lattice configuration. Its basic circuit structure comprises 3 dB directional couplers, two optical waveguides with equal optical path lengths, and two optical waveguides with different optical path lengths (an optical path difference of about 1 to 50 mm). Phase controllers for performing phase shift are provided on the optical waveguides. The portions with equal optical path lengths function as variable directional couplers, and variable directional couplers having arbitrary coupling rates can be constructed by changing the phase controllers on the optical waveguides with equal optical path lengths. As for an adaptive filter, there is adopted a construction in which a photodetector for withdrawing part of output is provided at the output port, and a feedback electric wiring for feedback control is laid. |
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DETAILED DESCRIPTION The present invention has been accomplished in the light of the conventional technologies discussed above, and it has the following objectives: (1) To realize, in a single filter circuit, an optical signal processor with a maximum transmittance of 100% capable of achieving the desired filter characteristics only by changing the circuit parameters set in the frequency region (improvement of an optical signal processor).
The present invention also aims at the following having four high grade characteristics: (2) To realize an optical signal processor with an arbitrary maximum transmittance of 100% capable of achieving the desired filter characteristics in the wavelength region (realization of a filter with an arbitrary wavelength characteristics).
(3) To realize an optical signal processor having arbitrary filter characteristics involving an arbitrary maximum transmittance of 100%, or more than or less than 100% (realization of an arbitrary maximum transmittance).
(4) To realize, in a single filter circuit, an optical signal processor which changes the circuit parameters so as to have predetermined desired signal processing characteristics in a time series manner (programmability).
(5) To realize an optical signal processor capable of changing signal processing characteristics in harmony with input signals which change over time (realization of adaptive property).
As described above, the present invention aims not only at improving the conventional technologies, but also at realizing high grade signal processing, and more specifically, the attainment of some or all of those four targets.
To attain the five objects set forth above, the present invention adopts circuit structures, controlling methods, designing methods, and production methods as described below.
DESCRIPTION (A) Before means for achieving an object of the present invention are described below, the coupling rates will be described which represent the characteristics of the variable directional couplers of constituent elements of the present invention
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Optical Systems 
