Optical modulator and controlling method and apparatus thereof
First Claim
1. An optical modulator that performs quadrature amplitude modulation with respect to an input light and outputs the quadrature amplitude modulated light, comprising:
- an optical branching section that branches an input light into (2×
N) lights (where N is an integer equal to or larger than
2);
(2×
N) phase modulating sections that respectively modulate the phase of respective lights branched by the optical branching section;
an optical coupling section that couples the phase-modulated lights output from the respective phase modulating sections and outputs quadrature amplitude modulated signal light having a 4N value; and
an optical phase adjusting section that relatively adjusts, with respect to an optical phase of specific two phase-modulated lights of the phase-modulated lights output from the respective phase modulating sections, the optical phase of the remaining (2×
N−
2) phase-modulated lights.
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Accused Products
Abstract
The optical modulator branches an input light into (2×N) lights in an optical branching section, and then phase modulates each of the branched lights in (2×N) phase modulating sections, and couples the phase modulated lights in an optical coupling section and generates a quadrature amplitude modulated (QAM) signal light having a 4N value. At this time, a relative difference of optical phases of the phase modulated lights is variably adjusted by an optical phase adjusting section. Moreover, a power ratio of the phase modulated lights is variably adjusted with an optical power adjusting section. As a result, it is possible to output 4N QAM signal light, with good signal quality.
31 Citations
31 Claims
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1. An optical modulator that performs quadrature amplitude modulation with respect to an input light and outputs the quadrature amplitude modulated light, comprising:
-
an optical branching section that branches an input light into (2×
N) lights (where N is an integer equal to or larger than
2);(2×
N) phase modulating sections that respectively modulate the phase of respective lights branched by the optical branching section;an optical coupling section that couples the phase-modulated lights output from the respective phase modulating sections and outputs quadrature amplitude modulated signal light having a 4N value; and an optical phase adjusting section that relatively adjusts, with respect to an optical phase of specific two phase-modulated lights of the phase-modulated lights output from the respective phase modulating sections, the optical phase of the remaining (2×
N−
2) phase-modulated lights. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An optical modulator that performs quadrature amplitude modulation with respect to an input light and outputs the quadrature amplitude modulated light, comprising:
-
an optical branching section that branches an input light into (2×
N) lights (where N is an integer equal to or larger than
2);(2×
N) phase modulating sections that respectively modulate the phase of respective lights branched by the optical branching section;an optical coupling section that couples the phase-modulated lights output from the respective phase modulating sections and outputs quadrature amplitude modulated signal light having a 4N value; and an optical power adjusting section that adjusts a ratio of the power of specific two phase-modulated lights of the phase-modulated lights output from the respective phase modulating sections, with respect to the power of the quadrature amplitude modulated signal light having a 4N value output from the optical coupling section. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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Specification