Optical modulator
First Claim
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1. An optical modulator comprising:
- an input optical path;
an optical splitter for splitting optical signal light input from said input optical path into N optical paths, wherein is an integer of 2 or more;
one or more of K-level optical phase modulators arranged in N−
1 of said N optical paths; and
an optical coupler for interfering output light from said N optical paths with each other in the same polarization state to send out interfered light as an output optical signal to an output optical path,wherein one of said N optical paths has no optical phase modulator and amplitude modulated light having amplitude values which is K raised to the power of N−
1 or less, or multilevel amplitude-and-phase modulated light modulated in both the amplitude and phase and having signal points which is K raised to the power of N−
1 or less, is output to said output optical path, by interfering output light from the N−
1 optical paths having said optical phase modulator with output light from the optical path having no optical phase modulator at the same phase or any phase angles other than ±
π
/2.
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Abstract
The present invention relates to an optical modulator that generates quaternary amplitude modulated light without inter-symbol-interference by splitting input light into three optical paths, generating a continuous wave signal in a first optical path, generating binary phase modulated lights using a single drive MZ type optical phase modulator in second and third optical paths, and interfering them at in-phase and at field amplitude 1:a:b.
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Citations
13 Claims
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1. An optical modulator comprising:
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an input optical path; an optical splitter for splitting optical signal light input from said input optical path into N optical paths, wherein is an integer of 2 or more; one or more of K-level optical phase modulators arranged in N−
1 of said N optical paths; andan optical coupler for interfering output light from said N optical paths with each other in the same polarization state to send out interfered light as an output optical signal to an output optical path, wherein one of said N optical paths has no optical phase modulator and amplitude modulated light having amplitude values which is K raised to the power of N−
1 or less, or multilevel amplitude-and-phase modulated light modulated in both the amplitude and phase and having signal points which is K raised to the power of N−
1 or less, is output to said output optical path, by interfering output light from the N−
1 optical paths having said optical phase modulator with output light from the optical path having no optical phase modulator at the same phase or any phase angles other than ±
π
/2. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An optical modulator for generating a modulated optical signal to an output optical path by splitting input light from an input optical path into N optical paths, wherein N is an integer of 2 or more, and by interfering output light from the N optical paths with each other, wherein:
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each of N−
1 optical path or paths among said N optical paths has a binary optical phase modulator for generating binary phase modulated light having signal phase points at phase 0 and phase π
, and one of said N optical paths has no optical phase modulator; andbinary or more levels of multilevel amplitude modulation or ternary or more levels of multilevel amplitude-and-phase modulation modulated in both amplitude and phase is applied to the input light input to said input optical path, by interfering at output light from the N−
1 optical paths having said optical phase modulator with output light from the optical path having no optical phase modulator at the same phase or any phase angles other than ±
π
/2. - View Dependent Claims (13)
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Specification