Bring a large pot of water to a boil over high heat. Salt the water generously, and let it return to a boil. Add the pasta, and cook accordingly to package directions, stirring occasionally.
While the pasta is cooking, heat the olive oil in a large skillet over medium high heat. Add the leeks and fennel and sauté for 8 to 10 minutes until the vegetables soften. Add the chicken broth and bring to a simmer.
Scoop out 1/2 cup of the cooking water. Drain the pasta and return it to the pot. Turn the fennel mixture into the pot with the pasta and add some or all of the reserved cooking water if the pasta seems dry. Toss to combine. Add the Parmesan and the bacon and toss to combine. Serve hot and pass additional Parmesan at the table.