DIFFERENTIAL M PHASE-SHIFT MODULATOR
First Claim
1. A differential M phase-shift modulator in which n (n is 2 or more) Mach-Zehnder type light modulators each adapted to output a DPSK-modulated signal light by applying a driving voltage signal are arranged in parallel;
- the modulator comprising;
a multiplexing waveguide adapted to output a DMPSK-modulated (M=2n) light by multiplexing outputs of the n Mach-Zehnder type light modulators, whereinthen n Mach-Zehnder type light modulators are adapted to be applied a phase-shift voltage to produce a phase shift difference of substantially 2π
/M for the n signal lights multiplexed by the multiplexing waveguide together with the driving voltage signal.
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Abstract
The present invention is a miniaturized differential M phase-shift modulator (M=2n: n is 2 or more) in which a plurality of Mach-Zehnder type light modulators each adapted to output a DPSK-modulated signal light by applying a driving voltage signal are arranged in parallel and that comprises a multiplexing waveguide adapted to output a DMPSK-modulated light by multiplexing outputs of the plurality of the Mach-Zehnder type light modulators, wherein a phase-shift voltage to produce a phase shift difference of substantially 2π/M for a plurality of the signal lights multiplexed by the multiplexing waveguide is applied to the plurality of the Mach-Zehnder type light modulators together with the driving voltage signal.
34 Citations
14 Claims
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1. A differential M phase-shift modulator in which n (n is 2 or more) Mach-Zehnder type light modulators each adapted to output a DPSK-modulated signal light by applying a driving voltage signal are arranged in parallel;
- the modulator comprising;
a multiplexing waveguide adapted to output a DMPSK-modulated (M=2n) light by multiplexing outputs of the n Mach-Zehnder type light modulators, wherein then n Mach-Zehnder type light modulators are adapted to be applied a phase-shift voltage to produce a phase shift difference of substantially 2π
/M for the n signal lights multiplexed by the multiplexing waveguide together with the driving voltage signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
- the modulator comprising;
Specification