A microwave-to-optical transducer

Theoretical predictions and initial experimental results show that intravalent absorption in semiconductors can be used to modulate light with electric fields that vary at 35 GHz. To produce electric fields of 50-1000 V/cm in a WR(28) waveguide, the author uses a microwave source that generates a 10- to 160-kW pulse lasting 100-ns. With this source, he can modulate more than 16% of the 3.39-μm light from a HeNe laser at 770K and more than 8% at 3000K. The percentage of modulation is better than expected. In this paper he develops the light modulation theory, presents initial experimental results, and speculate on how to build a practical microwave-to-optical transducer. He also points out that the transducer, fabricated from germanium, can be used to create fast rise-time optical pulses in the 2- to 4-μm region of the spectrum