All-optical signal regeneration based on gain-clamped semiconductor optical amplifiers

Research Area: III-V Semiconductor Photonic ICs

Main Researcher: Mingshan Zhao

Three novel all-optical 2R regenerators based on gain-clamped semiconductor optical amplifiers are investigated. The first one is a Mach-Zehnder interferometer (MZI) with identical gain-clamped SOAs (GCSOA's) in each arm. The operation of this regenerator is based on the specific property of a GCSOA that its amplification in the linear regime is independent of the injected current, whereas the saturation power increases linearly with the injected current. The device gives a true digital-like decision characteristic, a flexible adjustment of decision threshold and does not require wavelength conversion. The second one is a MZI with linear optical amplifiers (LOAs) in both arms. This device has similar operation principle and regenerative properties to those of the first one but higher operation bitrate potential. A good optical signal regeneration for 10 Gbit/s has been experimentally demonstrated. In addition to nonlinearies of gain and phase that governs the regenerative properties of the two former devices, nonlinear effective birefringence inducing polarization rotation is also an very interesting behaviour in semiconductor optical amplifiers. The third novel all-optical 2R regenerator is based on such polarzation rotation in a single LOA. With this device, an extinction ratio (ER) improvement of 15 dB has been obtained with an input ER of 5 dB for static operation. Experimental results for bitrates of both 2.5 Gbit/s and 10 Gbit/s have shown excellent dynamic regenerative performance of this device. The feature of simple configuration, stable operation and high regeneration capabilities make this new scheme a promising technique for all-optical regeneration in future optical networks.

2R regenerator based on MZI with GCSOAs

Other people involved:

• Mingshan Zhao

PhD thesises