Preheat oven to 180 degrees C. Bring a large pot of lightly salted water to a boil. Add pasta and cook for 8 to 10 minutes or until al dente; drain. Cook spinach according to packet directions; drain.
In a medium bowl combine chicken and one jar of alfredo sauce, stir together. In a separate bowl, combine ricotta and drained cooked spinach and stir.
In a 20x30cm baking dish place one layer of lasagne, edges overlapping. Pour chicken and alfredo sauce mixture over pasta layer and spread evenly. Sprinkle 1 cup of grated mozzarella over chicken mixture. Top with another layer of pasta. Spread spinach mixture evenly over pasta. Pour 1/2 of remaining jar of alfredo sauce over spinach mixture, spread evenly. Sprinkle another cup of mozzarella over sauce, lay on the final pasta layer and top with remaining 2 cups of mozzarella and salt and pepper to taste.
Bake 50 to 60 minutes, until top is brown and bubbly.