40 Gb/s optical wavelength converter converting the same wavelength using a single semiconductor optical amplifier

We present a high-speed optical wavelength converter that is capable of converting the data to the same wavelength using a single semiconductor optical amplifier. Error-free wavelength conversion is demonstrated at a bit-rate of 40 Gb/s. The wavelength converter utilizes counter-propagation scheme assisted by blue-detuned optical filtering technology. The counter-propagation configuration eliminates the pump data light, enable the wavelength converter to have the capability of converting the same wavelength. The blue-detuned optical filter shortens the recovery time of the wavelength converter, from initial 100 ps down to less than 6 ps, ensuring 40 Gb/s operation. In contrast to the ultra-fast gain saturation time in the co-propagation scheme, the counter-propagation scheme shows a slow gain saturation time, which becomes a determinant factor for the operating speed of the proposed system. The experimental results show that the slow gain saturation time can be cancelled by using the delayed-interferometer. Our results can also be applied to the other counter-propagation SOA-based optical switches. This wavelength converter is constructed by using commercially available fiber pigtailed components. It has a simple configuration and allows photonic integration.