Terahertz-to-Optical Carrier Conversion Using Optical-Comb-Injection-Locked Dual-Wavelength Laser Light and Electro-Optic Polymer Modulator

Prior to the use of microcomb, we used an electro-optic modulator optical comb (EOM comb,
$f_{rep}=10\ \text{GHz}$
). A pair of high-power CW lasers (wavelength
$\sim 1550\ \text{nm}$
) was injection-locked to two EOM-comb modes with a frequency separation of
$10f_{rep}$
, and then propagated through the optical waveguide of EOP modulator. RF beat signals of unmodulated optical carriers and modulated sidebands were detected when THz waves (frequency = 101 GHz) were irradiated to the EOP device. As the frequency difference between
$10f_{rep}$
and
$f_{THz}$
was 1 GHz, the RF beat signal between them was observed around 1 GHz, as shown in Fig. 2.