Terahertz transfer onto a telecom optical carrier

In a GaAs crystal, owing to the anomalous dispersion introduced by optical phonon absorption, a phase-matched interaction is possible between a near-infrared beam and a terahertz (THz) wave. We exploit this nonlinear optical process to allow the merging of THz-quantum-cascade-laser and telecom technologies by injecting a telecom beam into a suitably designed THz quantum-cascade laser. Within the optical cavity, the phase and amplitude of the THz wave are recorded onto the near-infrared beam, which can be transported through an optical fibre. We show that the process is phase-matched and can be tuned over the entire telecom range by waveguide engineering. This nonlinear up-conversion technique opens up new possibilities in the optical treatment of THz, by taking advantage of the highly developed telecom technology.

在砷化镓晶体中，由于光学声子吸收引入的反常色散，近红外光束和太赫兹波之间有可能发生相位匹配相互作用。我们利用这种非线性光学过程，通过将通信光束注入到适当设计的太赫兹量子级联激光器中，实现太赫兹量子级联激光技术与通信技术的融合。在光学腔内，太赫兹波的相位和振幅被记录到近红外光束上，该近红外光束可通过光纤传输。我们表明该过程是相位匹配的，并且可以通过波导工程在整个通信波段内进行调谐。这种非线性上转换技术利用高度发达的通信技术，为太赫兹的光学处理开辟了新的可能性。