Extending the Bandwidth of Photodiode-based Continuous-Wave Emitters to 5.5 THz

Optoelectronic continuous-wave THz generation by photomixing is an established tool for table-top spectrometers inside and outside of scientific laboratories. We present newly developed emitters based on ultrafast PIN photodiodes featuring 3 dB overall increased output power. At frequencies beyond 3 THz, the output power is up to >18 dB higher due to the reduced substrate thickness, i.e., internal absorption. As a result, a record bandwidth of 5.5 THz is achieved.

I. Introduction

During the last decades, remarkable progress has been achieved by the international research community regarding optoelectronic terahertz (THz) components and systems. This effort is driven by the multitude of possible applications in industry and science. These include spectroscopy, non-destructive testing, and wireless communications [1]–[4]. In particular, optoelectronic systems, which use photomixers to convert optical signals to the THz frequency range, have emerged as a prominent solution due to their large bandwidth and tuneability [1], [2], [5], [6].