HIGH SENSITIVITY WIDEBAND ANALOG FIBER OPTIC LINK

THE DEVELOPMENT OF AN ANALOG OPTICAL DATA LINK CAPABLE OF TRANSMITTING RF SIGNALS OF A MINIATURE SENSOR TO REMOTE DETECTION AND RECORDING SYSTEMS IS PROPOSED. THE SYSTEM IS BASED ON A SPECIFIC MINIATURE DIODE-LASER, A PIGTAIL SINGLE-MODE FILTER OPTIC CABLE AND A PHOTODIODE/AMPLIFIER RECEIVER. THE FREQUENCY RESPONSE, LINEARITY AND SENSITIVITY OF SUCH A LASER CONSTITUTES A VERY ATTRACTIVE CANDIDATE TO BE USED IN DIRECT MODULATION MODE BY RF SMALL-SIGNALS. SINCE THE MAXIMUM FREQUENCY OF THE MODULATING SIGNAL IS MODERATELY HIGH, AND SPECTRAL CHIRPING EFFECTS ARE NOT SIGNIFICANT FOR RELATIVELY SHORT LINK DISTANCES, WE EXPECT THAT NEGATIVE SIDE EFFECTS DUE TO DIRECT MODULATION OF THE LASER DIODE WILL NOT INFLUENCE THE PERFORMANCE OF THE SYSTEM. THE MAIN ADVANTAGE OF THIS CONCEPT IS ITS SIMPLICITY AND HIGH EXPECTED PERFORMANCE TO COMPLY WITH THE REQUIRED SENSITIVITY AND FREQUENCY RESPONSE FOR THE APPLICATION. A PROTOTYPE UNIT WILL BE DEVELOPED AND FULLY TESTED UNDER THE PHASE I EFFORT TO DEMONSTRATE THE FUNCTIONAL CAPABILITIES OF THE PROPOSED CONCEPT.