Gain peaking in TIA

Dear folks,

As part of an optical receiver system, I have a Transimpedance amplifier (TIA)  simulated using ADE-L simulator. 

This TIA has a significant gain peaking (close to 5 dB) in its frequency response characteristics, which starts around 30 GHz and is there upto 60 GHz.

I would prefer to have a flat response for the TIA using a suitable block or an enhancement technique after the TIA (and before the VGA).

I would need some insights about how to proceed further and make the TIA response flat, without affecting its bandwidth much.

Thanks and regards,

Tuka