basically I'm trying to make a plane with a solid colored center and I want it fades out to the edges of the plane (as the image below) on cycles.
Thanks in advance. Regards, Gonzalo
To Blur the Edges you could put a masking Texture (BW) into the fac of a mix node that mixes your prefered shader with an transparent shader.
I did it with a generated radial texture, but you could do it also with a premade texture, from your image editing software.
If you want a blur-node in blender look at Bashis work: https://www.blendswap.com/user/bashi
for simple shapes like rect and circle it would be possible via ramp and mapping for complex shapes you could do it possibly via python but its not simple!
So i think the best way for you is to do it with external software like photoshop. I prepared a workflow that creates the map from your shape so you dont have to approximate via drawing: