In my current setup the surge is going to hit the cable modem and will stop at the optical coupler.
Read what was posted. ADSL or cable modem makes no difference - other than 'installed for free' protection on cable is even better. A surge does not enter on a cable modem IF it is installed per electrical codes that have existed long before you or I existed.
Since the protection on cable is better, then the router is more likely to be destroyed by a surge.
With or without that optical cable, a surge will still be incoming on that same path (that is being ignored). It if does not find a best path to earth via a router, then it simply uses other appliances to get destructively to earth (ie central air). Optical cable may cure a symptom - a router. But does not solve the problem; a surge is all but invited inside.
Again, effective protection is never about 'blocking' a surge. Effective protection always (as in always) answers this question. Where do hundreds of thousands of joules harmlessly dissipate?
Best and effective solution only costs about $1 per protected appliance. It must exist to even protect a modem, all other networking equipment, and all other appliances. If it does not find earth via a router, then it can find earth ground destructively via every TV. What protects that?
Protect a router - and then make TV damage easier.
Your telco CO suffers about 100 surges with each storm. Did they disconnect everything to avert damage? Fiber optic cables did not exist. Was your town without phone service for four days after every storm? Of course not. Because an effective solution has been that well proven for that long. You did not have it. And still will not have it. A proven solution is still ignored.
I don't know how to make this any more obvious. That surge was not incoming on any ADSL, telephone, or TV cable (if properly installed - earthed). Somehow you don't get it.
Damage is often on an outgoing path - not an incoming one.
