Peel pears. Cut a small slice from bottom of each pear so it will stand upright.
Place pomegranate juice and port in a large covered skillet and bring to a boil. Place pears in skillet on their sides. Cover and simmer 40 to 45 minutes, until tender. Turn pears a few times so all sides color evenly.
Remove pears to serving plates. Cook poaching liquid over high heat 3 minutes, until thick and syrupy.
Spoon sauce over pears. Garnish with walnuts, crème fraîche and mint.