Wide band supercontinuum generation utilizing high nonlinear double clad Mach–Zehnder interferometer

Abstract Supercontinuum generation with improved coherence is very important issue in the optical communication system especially in the application of optical coherence tomography (OCT) that maintains the phase stability of the propagating pulse. In this work all fiber setups that consist of two interferometers were used to make compactness and alignment free compared with free space bulk optics setup, one with five nested Mach–Zehnder inferometer (MZI) and the second with Sagnac MZI interferometers. The sensing heads of the two interferometers high nonlinear fiber double clad fiber DCF13 that etched using 40%HF acid in four levels leads to decrease its diameter. Obtaining these levels is achieved by varying the time interval of the etching process as (10, 20, 30, and 40) minutes. Supercontinuum generation with Sagnac interferometer in this work has good performance when compared with nested MZI setup. This performance due to feedback the pulses and make counterclockwise propagating pulse that interfere with the clock wise pulse and leads to enhance the optical signal to noise ratio. The maximum OSNR was obtained that is 9.577 dB for Sagnac interferometer and 30 us rising time and 18 dBm amplification value of EDFA and 99.3 nW output power with 3 nm band (1,529.5–1,532.5) nm while for the first interferometer the output power in uW but with minimum OSNR that is 8.94 dB and −32.5 dBm noise power and 50 us rising time.