The main goal is to detect microVolts signal disturbance , low frequency , 10Khz using fiber-optics , by Homodyn down-conversion .
The source is very accurate 2Ghz from high Q OEO as very low noise & very low phase noise reference freq. It splits to 2 loops : one loop -use as LO to mixer and in the 2nd loop disturb AM modulation . to the RF port Mixer . We make Homodyn direct Down conversion to detect the disturbance s\n signal ( about microvolts 5Khz-10Khz) .
The phase of the RF signal ( through the fiber) is not stable . Than we think about I&Q down-converter .1- We choose the ADL5365 as non independent LO-RF , high isolation Mixer ..
2 - Is there Any I&Q mixer DownConvert with specs like the ADL5365?
3--Do we need 90deg shift between LO and RF to get the max. amplitude of the detected signal using the ADL5365? ( the Spec indicates non Independence between LO- RF ) ?
Can you please take a look at HMC381 and see if it fits your requirements. I think the problem will be at the IF frequency that it is min of 50MHz.
You need 90deg between IF1 and IF2 to get the max amplitude at the output.