Performance optimization of RoF systems using 120° hybrid coupler for OSSB signal against third order intermodulation

• This Paper includes analysis of the DEMZM based OSSBRoFsystem using 90° and 120° hybrid coupler Networks.
• The performance of RoF system with DEMZM has been optimized against third order intermodulation distortion by using 120° hybrid coupler in transmission system.
• SNDR is evaluated including the effects of third order intermodulation distortion and fiber dispersion in noise and distortion dominant environment.
• System design improvements are obtained by comparing results of both networks. All the analytical and numerical results are verified by simulations.

The performance of radio over fiber (RoF) system with dual drive Mach Zehender modulator has been optimized against third order intermodulation distortion by using 120° hybrid coupler in transmission system. Signal to Noise Distortion ratio (SNDR) has been evaluated and a performance comparison is also drawn for the systems based on 90° and 120° hybrid coupler in both noise and intermodulation distortion dominant environment. The SNDR is efficiently improved by employing 120° hybrid coupler in noise dominant and intermodulation distortion dominant environment. An improvement of 4.86 dB is obtained in the maximum SNDR with 120° hybrid coupler is obtained over at 20 km optical fiber length compared with a 90° hybrid coupler based system. A significant reduction of third order intermodulation power at receiver has also been observed with 120° hybrid coupler.