Sure you can use a MOSFET to drive a solenoid with a 1 amp coil. There are literally 100's of MOSFETs made and the choice of which one you could use will depend upon many factors. Here are some of the things to consider:

- What voltage supply will power the solenoid?
- What is the DC resistance of the solenoid coil?
- If the solenoid coil has high inductance what what type of diodes and / or TVS devices will be required to protect the MOSFET from the inductive spike that occurs when the switched state of the coil changes?
- Is there adequate Gate to Source voltage available in the FET drive to fully turn on the FET?
- Is the opto-coupler output so slow switching that it may be necessary to buffer the signal to square it up so that the FET switches quickly to reduce power loss in the FET itself.
- Must the input and output sides of the opto coupler share the same GND bus?
- Does consideration need to be made for the FET to be setup to be normally ON at start up?
- Do you have to switch multiple of the solenoids at the same time?
- What type of switching duty cycle and frequency would the FET be subjected to?

Michael Karas