Enlargement of dynamic range by hamming window in synthesis of optical coherence function

Summary form only given. The technique of distributed measurement by synthesis of the optical coherence function (SOCF) has been developed, and found various applications in optical reflectometry, distributed sensing, information processing and optical tomography. The SOCF adopts a stepwise light frequency modulation and a synchronous phase modulation to synthesize the coherence function into a narrow peak, and to scan it for distributed detection. Because of the discrete feature of the modulations, side-lobes appear beside the required main peak, and then limit the dynamic range of the system. In the presentation, a method to enlarge the dynamic range is proposed and demonstrated. The system configuration is a modified fiber-optic Mach-Zehnder interferometer illuminated with a 1.55 /spl mu/m tunable superstructure grating distributed Bragg reflector laser diode.