The first question is: where are the unwanted reflections that interfere genetared?
Sensor has a cover glass, and it is without antireflection coating, I guess. The solution is to apply antireflection coating at least on the front surface, but it could be very difficult to do for a sensor already mounted into the camera. Not sure that this is possible for the unmounted sensor as well.
Another option is to remove cover glass from the sensor, but this is a tricky surgery with a high risk of sensor damage.
The third option is to apply additional cover glass on the sensor, with antireflection coating of the front suerace and index matching gel between rear surface and front surface of the cover glass.
At least, the third method will work if interference is generated by a cover glass of the sensor. If the interference is generated by a sensor itself, one should look for another sensor, I guess...
