Compact optical modulator
View Patent ↗A novel design for an optical differential quadrature phase shift keying (DQPSK) modulator comprises two intensity modulators in a three-arm interferometer.
1. An optical modulator for generating a quadrature phase-shift keyed signal comprising:
an optical interferometer with at least three arms;
CHARACTERIZED IN THAT:
at least two of the arms each contain an intensity modulator;
wherein the interferometer has three arms, and the power ratios in the three arms are substantially 37% for each of the two arms containing the modulators and substantially 26% for the third arm.
2. The optical modulator of claim 1 , wherein one or more of the intensity modulators is an electro-absorption modulator.
3. The optical modulator of claim 1 , wherein the interferometer includes a reflective surface for reflecting light therein.
4. An optical modulator for generating a quadrature phase-shift keyed signal comprising:
an optical interferometer with at least three arms;
CHARACTERIZED IN THAT:
at least two of the arms each contain an intensity modulator;
wherein the interferometer has three arms, and the relative phase between the two arms containing the modulators is substantially +/−90 degrees, and the relative phase between the third arm and those two arms is substantially +/−135 degrees.
5. The optical modulator of claim 4 , wherein one or more of the intensity modulators is an electro-absorption modulator.
6. The optical modulator of claim 4 , wherein the interferometer includes a reflective surface for reflecting light therein.