One destination for visa holders is the Truebright Science Academy, a charter school founded in North Philadelphia by followers of Gulen.
An analysis of H1-B visas conducted for The Inquirer showed that the number granted for Gulen charter schools has grown substantially since that 2006 report. More than 2,500 have been issued since 2007.
U.S. Citizenship and Immigration Services granted 509 of the H1-B visas in 2007. In 2010, the total was 839 - a 65 percent increase.
Truebright, which opened in 2007 and has 348 students in seventh through 12th grades, has received 21 visas, including for a school director, counselors, and math and chemistry teachers.
As a public charter school approved by the Philadelphia School District, it receives more than $3 million a year in district money.
The acting chief executive at Truebright, Tansu Cidav, has declined to discuss the school's operation.
Turkish staffers at Truebright are paid more than their American counterparts, state pension records show. In the last school year, a Turkish math teacher who was not certified and spoke little English was paid $54,000; a certified American science teacher was paid $40,200.
Gulen, who is in his early 70s, lives in self-imposed exile in an enclave in Saylorsburg, Pa. A federal judge in Philadelphia granted Gulen a green card in 2008 after Gulen appealed a Department of Homeland Security ruling that he did not meet the criteria to qualify as an "alien of extraordinary ability."
In his appeal, he emphasized his renown as an educational figure. A spokesman for Gulen, Bekir Aksoy, told The Inquirer recently that Gulen had no ties to the charter schools, of which there are more than 120 in 25 states. Aksoy said Gulen may have inspired his followers to found the schools.