The Ottoman Empire was a large Islamic Empire which controlled the Southeast Europe, Western Asia and North Africa.
The European countries traded with Asia or east for goods and spices had to pass through Ottoman Empire as the later controlled all trade routes to Asia. The Ottomans and other Muslims kingdoms had a monopoly of trade therein and thus the trade was very expensive. In 1453 The Ottoman Empire captured the Constantinople and gained control over Middle East and we see the trade between Europe and Asia stopped abruptly. So the Europeans began to find alternatives in Sea routes and explored more and more countries. In this way Ottoman Empire indirectly encouraged the Western European Age of Exploration in 15th century.