According to section 4.3 of the rules, if you have a Shield rating of at least 1 then even after piercing is taken into account the firer still needs to roll more than 1 on each impact die. Therefore a Shield rating of 1 is very useful (and cheap) if you opponent uses lots of Piercing +3 weapons. Ignores Shields would still get through however.
With regards to the Pulse Lasers, if you are intending them to be used mainly as anti-fighter weapons you should be aware of a couple of things:
1) You don't use Impact or Damage against fighters so I would make them Impact 1 which will save space for something else.
2) Fighters move after ships and fire before them. As a standard fighter flight can move 10 hexes in any direction they can zip in from outside your anti-fighter weapon range and shoot you before you can do anything about it.
Therefore I would propose the following choices:
1) If you want your ship to only defend itself against fighters then use Anti-Fighter Batteries and Point Defense.
2) If you want it to destroy fighters at range then I would suggest a high ROF, range 12 or more, Anti-Fighter Trait (and maybe Fighter Exclusive), and either Inverted Range modifiers or No Range Modifiers. Increased Hits may also be of use. Any fighter attacking your ship will then have to take at least one turn of fire before it can attack you.
3) Carry your own fighters to defend your ships.
A short range anti-fighter weapon is only useful if you are happy to fire after you have been shot and you are operating as a small squadron and want to be able to provide covering fire to whichever ship is currently under fighter attack (assuming you aren't all under attack).