High-resolution digital phase modulator for a fiber-optic signal transmission or measurement device

A digital phase modulator for a fiber-optic signal transmission or measurement device, which has a predetermined total number of electrodes of different length which are arranged parallel and on both sides of a light guidance path in or on an optical substrate, in which case identical control potentials can be applied to the electrodes on both sides of the light guidance path, in such a way that a large number of phase values for a light wave which is running on the light guidance path can be set by changing the drive selection of electrode combinations within a predetermined value range, characterized in that

• the electrodes are arranged in two or more triples along the light guidance path, with
• the longest electrodes of successive triples having the same length ratio with respect to one another from the second to the most significant triple,
• the electrode length ratios of the electrode triples above the first low significance triple being defined such that the length of the respectively shortest electrode value is:
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• =
• l
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• ,
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• =
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• ∑
• i
• =
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• (
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• =
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• for
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• {
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• where the index “I” denotes the triple number and the indes “j” indicates the number of the respective electrode in the triple, and
• the length of the respective central electrode is governed by the relationship bx=2ax, and
• the length of the respectively longest electrode is given by the relationship cx=ax+bx, and
• the electrode lengths of the first, least significant triple being chosen such that the smallest step widths of the light phase in the output value range of the phase modulator can be formed by subtraction between the associated phase values of at least two larger electrodes, and
• in order to reduce the length ratio of the longest to the shortest electrode in the modulator in the lowest triple, its electrodes are relatively lengthened such that an additive combination of the values of the two shorter electrodes results in the length value of the longest electrode in this lowest triple.