Experimental investigation on gain-dependent chromatic dispersion of the semiconductor optical amplifier

•A simple method is used to measure the dispersion of SOA over the range of 80 nm.•The dispersion can be adjusted by changing the bias current and the input optical power to SOA.•Under the optimal experiment condition, dispersion curves have same characteristics.•Increasing bias current will broaden the three near-zero dispersion regions.•Increasing the input optical power will narrow the near-zero dispersion regions.

Using a chromatic-dispersion analysis method based on K–K transformation of the gain spectrum, we experimentally investigated the chromatic dispersion of semiconductor optical amplifier in detail within the wavelength range from 1530 nm to 1610 nm. Experimental results demonstrate that there are three typical dispersion regions, which are abnormal dispersion, flatten dispersion and normal dispersion region, and three zero-dispersion points, which exist around 1550 nm, 1580 nm and 1600 nm, over the wide wavelength range of 80 nm. With an increase in bias current on SOA, wavelengths of the three zero dispersion points all had a blue shift and the three near-zero dispersion regions corresponding became wider. However, the three near-zero dispersion regions corresponding became narrower when the input optical power increased. Therefore, the dispersion of SOA can be flexibly adjusted by changing the bias current and input optical power to SOA.