For signals to be switched, up to what frequency can be used?

For signals to be passed through the switch between the output terminals in a photorelay, the degree of damage on their waveform quality varies depending on the performances of COFF, the output capacitance when the photorelay is OFF, and RON, the resistance between the output terminals when the photorelay is ON (ON-state resistance). Products in a product series with these RON and COFF being small can even handle GHz signals. They can also be used for tester applications.