A temperature sensor comprising an optical transducer member having an array of birefringent crystals. The length and, accordingly, the sensitivity to temperature change of successive birefringent crystals varies according to a particular relationship. The transducer is interconnected with a fiber optic transmission and detecting system. Respective optical output signals that are transmitted from the birefringent crystals via the fiber optic transmission system are detected and decoded so as to correspond to digits of a numbering system, whereby an accurate digital representation of temperature can ultimately be provided
