An optical module couples a fiberoptic catheter to a catheter oximeter processing apparatus. The module includes a plurality of LED's for coupling the electrical control signals from the processor and converting them to light signals to transmit to the catheter. The module also includes the means to convert the received reflected light signals from the catheter to electrical signals to be transmitted to the processor. The module further includes a memory to store calibration signals and other data so that the module and catheter can be disconnected from the processor and used with a different processor without necessitating a recalibration.