Photonic‐Assisted Microwave Signal Processing

Microwave signals can be processed in the electrical domain based on analog or digital electronics. This chapter focuses on the design and implementation of microwave filters and microwave up or down converters based on photonics. In an optical microwave signal processor, in addition to the functionality of microwave filtering, optical microwave mixing is another important functionality which can find applications in radio-over-fiber systems and other microwave systems for microwave frequency up- or down-conversion. The chapter provides introduction to optical microwave mixing. A microwave photonic filter can be implemented in coherent regime using a single wavelength light source. An incoherent microwave photonic filter usually has a spectral response that is periodic. The use of high-power handling PDs may increase the noise performance, but the dynamic range can be improved by using techniques such as pre- or post-linearization which should be done in the electronic domain, making the filters complicated and costly.