As a graduate student at MIT, she conducted her doctoral work under Rainer Weiss, where Mavalvala developed a prototype laser interferometer for detecting gravitational waves. After graduate school, she worked as a postdoctoral researcher and then as a research scientist at the California Institute of Technology, starting her work with cosmic microwave background, and then eventually working on the LIGO. Mavalvala focuses primarily on two fields of physics: Gravitational Waves Astrophysics and quantum measurement science. Mavalvala joined the MIT physics faculty in 2002. In 2017 she was elected to the National Academy of Sciences.