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.