I think its important for you to communicate to your employer that as a designer, even though you’re updating your portfolio it doesn’t mean you’re jumping ship or looking for something new necessarily. Designers love to share, and a portfolio is a good source for them to get attention and share what they have done and the importance of it. It could actually help certain companies when people see that they have super talented designers on staff. However, I would be honest and review your NDA (If you have one, which I would hope you do) and other forms highlighting the secrecy of your work, and just make sure what you share is not in violation of these documents.