Sen said: "His (Alam)'s work should receive praise and appreciation, rather than being ground for harsh treatment."
Alam was arrested in the first week of August following his interview by a news channel in which he criticised the Bangladesh government's violent response to a peaceful protest by the students.
"Freedom of expression, including through photojournalism, is extremely important for democracy. We have a good reason to admire the work that Shahidul Alam has been doing with great skill and courage for many years," said Sen in a press statement.
Nobel laureates, activists and journalists from across the world have demanded immediate release of the Bangladeshi photographer.