Wifi Signal Coupling to Analog

I have a system where I have sensitive high gain optical amplifiers. The amplifiers has gain around 6M times. In the same system, I also have a wifi module. The construction of the system is such that

Wifi - module (TOP)
------------------ Plastic divider
Analog Front End (Bottom)

The AFE picks up wifi during receive. The AFE doesn't go up to 2.4GHz, it is rather the RF field charges the ground of the AFE and amplifier amplifies this and I see it at the output. I slapped a EMI absorber to the plastic divider and problem is solved but Wifi is now 10db weaker and distance is reduced. How can I attack this problem?

I have through about changing the antenna on Wifi and make it more directional (Cone shape where it doesn't emit down). Shield the AFE (which I really don't want to touch since it is complex design and previous attempt to shield increased noise). Other solutions?

Thx, Kt.

Can you shield one of them ?Or both ? The single practical solution that you may apply..
Picks may also come from power supply if they share the same supply lines. Ferrite beads will cutt-off the interference.
Grounds are also important if they share some ground lines ..

You can add one GND layer between the Top and bottom to isolate them.