Reception of modulated optical radiation using radio heterodyning in a photomultiplier tube and double light modulation

Two systems for the reception of modulated optical radiation which are based on modulation-frequency conversion are investigated experimentally in the 10-150 MHz range: (1) radio heterodyning in a photomultiplier tube and (2) double light modulation (DLM). The radio-heterodyning technique can produce frequency conversion using low control voltages of 1-3 V. The maximum frequency that can be received through the use of the radio heterodyning technique exceeds 100 MHz; this band is significantly higher than the amplitude-frequency response band of a standard photomultiplier tube. The DLM system requires considerably higher control voltages but is characterized by a greater noise immunity than the radio heterodyning system.