Reciprocating Optical Modulation on Erbium-Doped LiNbO $_{3}$ for Harmonic Generation

We demonstrated reciprocating optical modulation using erbium-doped LiNbO3 crystal for high-order sideband generation and selective amplification. A Ti-diffused waveguide, formed on the crystal, had a gain of 2.1 dB/cm for 1531.4-nm signal light pumped at 1480 nm with a pump power of 200 mW/port. A sideband component of 40 GHz was successfully enhanced and a gain of 12 dB was realized.