Optical fiber pressure transducer

Apparatus for use in measuring blood pressure at a remote location within a blood vessel and comprising:

• an elongated flexible fiber optic member of a size sufficiently small to be inserted into a said blood vessel and having a light transmitting core coaxially surrounded by cladding means essentially throughout its length, said core being uncladded for a portion of its length adjacent the distal end thereof;
• pressure transducer means located adjacent said distal end alongside said uncladded portion, said transducer means being constructed of flexible light absorbing porous material having an index of refraction greater than that of said cladding means and having a pitted surface portion facing said uncladded core portion making interrupted multiple surface area contact therewith throughout the area that said surface portion faces said uncladded portion such that the total surface contact area varies with pressure forces applied to said transducer means acting transversely of said uncladded core portion whereby the intensity of any light passing through said core portion proximate to said contact surface area can be modulated inversely proportional to the magnitude of said pressure forces, said porous material having interconnected pores of sufficient size to vent air from locations between said uncladded core portion and said pitted surface portion.