You can copy and paste all needed keyframes all at once in the dopesheet or action editor, or you can use the repeat function in the Nonlinear Animation Editor.

You can copy and paste all needed keyframes all at once in the dopesheet or action editor, or you can use the repeat function in the Nonlinear Animation Editor.

Anyway, to answer the question, you can add a modifier to one channel, tweak its values then click its copy button, then select all the needed channels and click paste button.