So I work as a Junior Software Developer for this company. During the interview process for this company I had to show the software that I had previously developed. I had developed a system (Web Application) previously and presented it to the interviewers (Who I now work with) 6 months ago. The system I had developed fits well with the existing systems in place at the company and In the interview they had said it was a good idea.
All has gone well and I've been employed at the company for 6 months with no issue. I am now trying to figure out the correct way to approach my boss (who was not in the initial interview and has no knowledge of the system) and convince him that its a good idea for me to re develop the system and make it the companies 75-90% of the system would become the companies and 25-10% of the system would still be mine. I would develop the system for an hour or two for free every day after work until its completion. Not sure how to structure the ownership of it correctly yet (Maybe use some kind of royalty structure).
My question is
What is the best way to approach my boss with the concept and what would the ramifications be? Also I work in the same building as the CEO and he said his phone was always open to call him would that be a better option?