Rotor thrust balancing systems for turbomachines and methods of using the same are generally disclosed. For example, a rotor thrust balancing system for a turbomachine, wherein the turbomachine defines a centerline extending the length of the turbomachine. The system includes a rotating drive shaft, a thrust bearing, and a first waveguide sensor. The rotating drive shaft couples a turbine section and a compressor section of the turbomachine. The thrust bearing supports the rotating drive shaft of the turbomachine. The thrust bearing includes a plurality of ball bearings, an inner race coupled to the rotating drive shaft, and an outer race coupled to a fixed structure. The first waveguide sensor is coupled to the outer race at a first end of the waveguide sensor. The waveguide sensor communicates a vibrational frequency from the thrust bearing to a second end of the waveguide sensor.