The Research On Frequency Response Of Gain-Clamped Semiconductor Optical Amplifier

The rapid growth of bandwidth demands drives the evolution of optical accesstechnology to next generation passive optical network (NG-PON). With obvious advantagesin network security, transfer rate, etc. wavelength-division-multiplexing PON (WDM-PON)is regarded as the ultimate solution for optical fiber access. As a transitional scheme fromtime-division-multiplexing PON (TDM-PON) to WDM-PON, hybrid TDM/WDM PONcombines the advantages of them and causes widespread concern in the industry. Thisdissertation launched the research on frequency response of gain-clamped semiconductoroptical amplifier (GC-SOA), for the needs of wavelength conversion and linear amplificationin NG-PON. The main contents of this dissertation are as the following:A gain-clamped SOA based on fiber-Bragg-grating structure is proposed. Operationprinciple is analyzed, and the mathematical model of frequency response is established basedon rate equation and small-signal analysis. The effects of structural parameters and workingconditions on frequency response are analyzed and the variation of wavelength conversionand linear amplification are obtained.When used for wavelength conversion, the effects of bias current and input power onfrequency response of GC-SOA are researched by experiment. The results indicate that whenthe rate of input signal is less than2.8GHz, namely the3dB modulation bandwidth, theGC-SOA can realize wavelength conversion while the opposite is not.As for linear amplification, a novel structure of GC-SOA is proposed to reduce theresidual reflection. The effects of distribution losses, input power, channel spacing andwavelength shift on the system performance are simulated, for the needs of GC-SOA inlong-reach WDM-PON. The results show that when the attenuation of GC-SOA isappropriate, channel crosstalk will be avoided and the sensitivity of system can be improved.