OK, you don't bridge subs. You bridge amps, if they are capable of being bridged (not all are).
Bridging is a method of connecting the channels of a multi-channel amp in such a way that the amp delivers the output of 2 stereo channels into a single mono load.
The Polk DB1040DVC is a sub with dual 4ohm voice coils. You can wire the voice coils to present a final 2ohm load (parallel) or a final 8ohm load (series). The rated power range is 50-270 watts RMS. Since you can parallel the voice coils and have them present a 2ohm load to the amp, you are looking for an amp that provides a minimum of 50 and a maximum of 270 (round it up to 300) watts into a 2ohm load. The Rockford-Fosgate Punch 300.1 shown here for $170
seems tailor made for your Sub. If you can make do with less power and want to spend a little less money, the Orion Cobalt CO500.1 will deliver 250 watts RMS at 2ohms and you can buy it for $140
. The punch is a better deal. If you decide to add another sub later, it will power them both with 150 watts each, a little low, but still decent. If you want a 2-channel bridgeable amp, I'd recommend the Kicker 08DX3002
shown here for $200. Note that in bridged mode, it is not stable at 2ohms, only down to 4ohms.
Hope this helps.