Generation of Local Oscillator Signal via Photomixing

Abstract

Overview: This chapter investigates the possibility of down-converting the output of two commercially available infrared lasers to generate a local oscillator (LO) signal at sub-mm wavelengths, for working in conjunction with balanced SIS mixers. The main motivation here is to utilise the ability of a balanced mixer to reject the LO amplitude noise, which may prevent the use of a photonically generated LO signal as part of a heterodyne receiver system. In the first part of this chapter, we shall introduce the principle of photomixing for generating LO signals, and report on the successful operation of using the photonic LO to pump a 230 GHz single-ended SIS mixer. We will then describe an attempt for locking the two lasers to produce a stabilised LO output.