A Day in Your Life at MKS: MKS Systems Irvine is growing very rapidly with significant strategic investments in the development and fabrication of cutting-edge, high precision optics, opto-mechanical assemblies and systems. To manufacture these products, Systems Irvine is seeking individuals like you to join our team as Principal Optical Systems Engineer. In this position, you will plan, conceptualize, design, test, and document complex, high-precision opto-mechanical / electro-optical products.