A balloon catheter has a balloon membrane, a tip connected to the distal
end of the balloon membrane and an outer tube connected to the proximal
end of the balloon membrane for supplying a medium for inflating and
deflating the balloon membrane. A pressure sensor, such as a fiber optic
sensor, may be mounted in a pocket in the tip. The pocket may be filled
with a flexible substance which both communicates pressure to and
protects the pressure sensor. A membrane may overlie the pocket to
prevent leakage of the flexible substance therefrom.