A Compact Photonics-Based Single Sideband Mixer Without Using High-Frequency Electrical Components

Abstract

A new microwave photonic frequency up converter is presented. It is capable to generate an up converted upper or lower sideband RF signal with the other sideband and the LO being suppressed. Compared to the reported photonics-based single sideband (SSB) frequency up converters, the proposed structure is simple and does not require high-frequency electrical components. The upper or lower sideband can be selected by controlling a modulator bias voltage. The new photonics-based SSB mixer is experimentally verified. Around 30 dB suppression in the undesired frequency components adjacent to the up converted RF signal is demonstrated for different input LO and IF signal frequencies when the SSB mixer is operated in either upper or lower sideband mode.

Photonics-Based Single Sideband Mixer With Ultra-High Carrier and Sideband Suppression

“…The results demonstrate the SSB mixer can be operated over a wide frequency range. Furthermore, both the conversion efficiency and the carrier and sideband suppression are around 10 dB higher than all the reported photonics-based SSB mixers [9]- [14]. The 1-dB compression point of the SSB mixer was also measured.…”

“…The RF signal is generated by two sets of LO and IF sidebands beat at the PD. This results in a 6 dB higher conversion efficiency, which is defined as the ratio of the output RF signal power to the input IF signal power, compared to the reported SSB mixer that uses an optical filter to remove either the upper or lower LO sideband [14]. The proposed SSB mixer has a simpler structure compared to the reported SSB mixer that requires path length matching between a polarisation beam splitter and two PDs [13], which is difficult at millimeter wave frequencies.…”

“…It also has the potential to reduce the system size and cost via eliminating an external electrical LO source [1]. Hence, numerous microwave photonic mixer structures have been reported [2]- [14]. Among them, only few are focused on single sideband (SSB) mixing [9]- [14].…”

“…Hence, numerous microwave photonic mixer structures have been reported [2]- [14]. Among them, only few are focused on single sideband (SSB) mixing [9]- [14]. A SSB mixer is used for up converting an IF signal with a frequency of fIF into an RF signal at the frequency of either fLO+fIF or fLO-fIF where fLO is the frequency of the LO into the mixer.…”

Microwave Photonic Frequency Translators With Large Spurious Suppression and Wide Bandwidth

“…It should be emphasised that using the conventional microwave photonic mixers or frequency converters [16], [17] for frequency translation has the problem of the carrier and sidebands being present at the frequency translator output, which interfere with the frequency translated signal. There are few reports on microwave photonic based single sideband (SSB) mixers [18], [19] in which the carrier and sidebands are suppressed. However, they are unable to realise frequency translation with >35 dB spurious signal suppression and have a complex structure.…”