Experimental investigation of the cascadability of a cross-gain modulationwavelength converter

The cascading characteristics of a wavelength converter based on cross-gain modulation (XGM) are studied experimentally using a recirculating loop at 10 Gb/s. The maximum cascaded number of the wavelength converter converting the signal to the same wavelength is improved from five to eight by adding a fiber grating-based optical add-drop multiplexer after the semiconductor optical amplifier (SOA) to enhance the high-frequency response of the wave length converter. However, the low-frequency degradation of the signal toge ther with amplified spontaneous emission (ASE) noise and jitter accumulatio n finally limits the wavelength converter to he cascaded for more times.