Wideband Single Sideband Modulation of Optical Carriers
Patent application, Filed 23 Feb 2000
DEPARTMENT OF THE NAVY WASHINGTON DC
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The wideband single-sideband modulator generates single-sideband SSB modulation with suppressed carrier utilizing traveling-wave LiNbO3 modulators in a Sagnac loop. In the wideband single-sideband modulator, optical light from a linearly-polarized source is injected into polarization-maintaining fiber PolMF where it is split equally via a Polarization-maintaining PolM directional fiber coupler, resulting in counterpropagating lightwaves in a Sagnac loop. These counterpropagating waves are II2 out of phase due to the action of the coupler and remain so when they return to the coupler because they travel equal distances around the loop. Because the coupler is a reciprocal device, if the waves return to the coupler with equal amplitudes, they will recombine and exit the original port toward the polarized light source. The technique achieves true carrier cancellation over a range of V radio frequency RF power levels, thereby serving as an enabling architecture for photonically-remoted ultrawide-band single- sideband suppressed-carrier SSB-SC modulated links.
- Fiber Optics and Integrated Optics
- Radio Communications