The Study On Characteristics Of Tunable Integrated Devices Based On The SGDBR Laser

Tunable semiconductor lasers are one of the key devices in the next generation all-optical dynamic networks. They can be used as wavelengths backup and inventory management for reducing system cost. Moreover, they can be used in the reconfigurable optical networks to provide automatic wavelength configuration, tunable wavelength conversion and wavelength routing, which extremely enhance the flexibility and the efficiency of optical networks. Monolithic integrated tunable lasers are the preferred option in the dynamic optical networks due to their wide tuning range, small size, fast wavelength switching, and also they can be monolithically integrated with other devices such as semiconductor optical amplifiers (SOA) and modulators. In this thesis, sampled grating distributed Bragg reflector (SGDBR) lasers and SGDBR lasers with integrated SOA (SGDBR-SOA) are investigated both in theory and experiment. The main contents are as follows:(1) The basic principles of semiconductor lasers is introduced first, and then based on the analysis of the distributed Bragg grating (DBR) and sampled grating, the wavelength tuning principle of DBR lasers and SGDBR lasers are described.(2) Comparing different modeling methods of semiconductor lasers, we chose the transmission-line laser model (TLLM) for analyzing the SOA-SGDBR integrated devices. Based on the TLLM, a time-domain large signal laser model is established for the SOA-SGDBR integrated devices. The static and dynamic properties of SGDBR lasers are simulated and analyzed, and also the influences of the integrated SOA on the direct modulation performance are studied.(3) Based on the wavelength tuning principle, an automatic wavelength test system has been designed and established for wavelength scanning of SGDBR lasers using the software LabVIEW. This system can automatically scan the bias current of laser, collect and analyze its output optical spectrum, and then generated"current-wavelength/optical power/side mode suppression ration"date query table. Then based on the experimental results, the static tuning characteristics of SGDBR lasers are analyzed.(4) Based on the control circuit board of the SOA-SGDBR integrated devices, wavelength switching dynamics of SGDBR lasers have been experimentally studied. Moreover, we studied the control mechanism of the integrated SOA and the improvement of wavelength switching dynamics of SGDBR lasers by using the integrated SOA as a shutter. The output power of the SOA-SGDBR integrated devices will oscillate during the shuttering processes. The mechanism of this phenomenon is analyzed by using the transmission-line laser model.