A birefringent active fiber laser sensor includes one or more fiber lasers 12, 14, 16, each having a pair of Bragg gratings 18, 20, embedded in a fiber 10 and excited by a common pump light 30. At least one of the lasers 12, 14, 16 has a laser cavity wit a predetermined birefrigence and a lasing light...http://www.google.es/patents/US5564832?utm_source=gb-gplus-sharePatente US5564832 - Birefringent active fiber laser sensor
