This was most likely done by using a light gel (that contains the caustic pattern of the waves refracting the light of the sun) on a spotlight, which was then hidden in the scene.
Doing this in Octane is possible, but requires s very specific setup.
1.) As Paul mentioned, you need a very high-res ocean plane (normal and/or displaced surface would be preferable)
2.) Set your Caustic blur setting to 0.0
3.) Use the Daylight environment, to get a light strong enough to cause these caustics.
4.) Try rendering and re-rendering, it will be tricky to achieve, but it is definitely possible.
Another (fake) way, to get this done would be to use a plane with a caustic map placed in the distribution channel of the light. Should roughly give you the same effect.
Hope this helps.
You can see an example scene (rendered with the OctaneRender for Cinema4D plug-in) right here:
http://elasticpictures.com/1005/cinema-4d-octane/
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