Boil 3 quarts water in a 4-quart pot. Cook pasta according to package directions and drain.
Meanwhile, cut skin from trout. Cut trout into 4 portions. Season with salt and pepper.
Heat a 12 inch non-stick skillet over medium-high heat. Spray with non-stick cooking spray. Cook trout 3 to 5 minutes per side, depending on thickness. Remove skillet from heat.
While fish cooks, combine broth, sugar, vinegar, soy sauce and cornstarch in a 1-quart saucepan. Bring to a boil over medium-high heat and cook 1 minute; stir constantly.
Divide noodles evenly among 4 plates. Top with trout; spoon glaze over each portion. Sprinkle with green onion and serve immediately.