Northrop Grumman will sell its Electro-Optical Systems business to L-3 Communications for $175 million in cash, the companies said Wednesday. The deal is expected in the second quarter. Electro-Optical Systems, a part of the company’s Electronic Systems sector, produces night vision and applied optics products and had sales of about $190 million in 2007. Headquartered in Garland, Texas, Electro-Optical Systems has about 1,000 employees.