I would like to ask if it's possible to optimize the design of an existing cam in order to reduce its weight, or even make its surface smoother so there will be no jump in the motion of the follower.
In addition, there is an attached file of a cam
To reduce weight, you'll need to remove material, or use a low density material. Without knowing all the details of how the part is used and created, it is not possible to offer detailed suggestions.
SolidThinking has a cool program called Inspire that helps calculate unneeded material in a model. I think you'd be best served by simply making some holes in the part to reduce mass, but you could have a cool truss system instead if this will be a printed or cast part instead of a machined piece: http://www.solidthinking.com/ProductOverview.aspx?item=Inspire%20Overview&category=Products
The base sketch has all of the lines and arcs tangent to each other, so the motion should be smooth. If it needs to be smoother, you could re-sketch the profile with splines, or conic sections. Those will allow you to make curvature continuous relationships which will be smoother.