Christian Ott, who campus officials determined committed "unambiguous gender-based harassment" of the students, will resign effective Dec. 31, Caltech President Thomas F. Rosenbaum and Provost Edward M. Stolper wrote in a letter to students and faculty on Tuesday.
A university committee was trying to determine whether to reinstate Ott as a professor. Ott was placed on unpaid leave, barred from campus and required to undergo training after an internal investigation in the fall of 2015, officials said.
On Tuesday, Stolper and Rosenbaum wrote that the evaluation from the committee and others showed that Ott "made significant progress with regard to the issues that led to the disciplinary action against him," but because of his history "remained a divisive element on campus."
"This has been a difficult situation for our community," Rosenbaum and Stolper wrote.
The accusations against Ott were first reported by BuzzFeed.
Ott, who was considered a rising star at the school and had recently been granted tenure, fell in love with one of his graduate assistants, then fired her from her job working with him researching supernovae, BuzzFeed reported. He wrote about his actions and his feelings for the woman in months of messages to another female graduate student, the website said.
Both women filed harassment complaints about him, according to BuzzFeed. They told the news outlet that they were disappointed that the school took a rehabilitative approach rather than firing Ott.
The woman Ott was in love with, according to BuzzFeed, did not realize he had romantic feelings for her and thought she had been fired because she had not done her job well.
Several days after telling the woman he didn't want to work with her, Ott sent her a message: "Of all my students I cared most about you and I failed in the worst way," BuzzFeed reported. "My problem is that I don't want to be in a power position, but I factually am."
Ott also posted 86 poems about the woman on his Tumblr page, BuzzFeed reported. The poems have been taken down.