In a large pot of salted boiling water, cook the fettuccine according to package instructions until al dente. Drain and set aside.
In a medium bowl, toss the shrimp with Cajun seasoning, ensuring they are well coated.
In a large skillet, heat olive oil over medium-high heat. Add the seasoned shrimp and cook for about 2-3 minutes on each side until they turn pink and opaque. Remove shrimp from the skillet and set aside.
In the same skillet, add the minced garlic and diced bell peppers. Sauté for about 3-4 minutes until the peppers soften.
Pour in the heavy cream and chicken broth, then stir to combine. Bring the mixture to a gentle simmer.
Add the cooked fettuccine to the skillet along with the sautéed shrimp. Toss everything together until well coated in the sauce.
Stir in the lemon juice and season with salt and pepper to taste. Cook for an additional 2-3 minutes to heat through.