I'm using and Arduino, an IR Led, and a transistor to for sending RC5 signals (36khz).

For the next step I need to be able to adjust the brightness of the signal, basically changing the range. The value could be set by an analog signal, spi or i2c or anything basic.

I thought about using a digital potentiometer, but they are not taking enough current for the LED - should be up to about 250mA (for a short time).
Searched the web but really not sure how to approach this. How do I create a circuit to adjust brightness for IR remote signals?