| Summary: | 碩士 === 國立臺北科技大學 === 光電工程系所 === 94 === In this thesis, we propose and demonstrate a bidirectional radio-on-DWDM transport system based on external light injection technique and adaptive filter.
First of all, we propose a bidirectional radio-on-DWDM transport system based on external light injection technique and the 1.55-μm wavelength vertical-cavity surface-emitting laser（VCSEL）technology. The broadband amplified spontaneous emission (ASE) light source, which is supplied by EDFA output light source. The high-power ASE from an EDFA can be efficiently divided into many channels by using a WDM demultiplexer（DEMUX）or optical bandpass filters（BPFs）. Therefore, the broadband ASE optical source can be changed into a similar DFB laser diode characteristic by using the optical BPF. Using an external light injection technique can effectively enhance the frequency response and reduce the driving current of VCSEL.
Second, an adaptive filter has been employed in the microwave fiber-optic link to compensate the nonlinear distortion. The adaptive filter has to achieve original Signal from distortion Signal by error feedback. For amplitude compensation, the output of the amplitude compensator is compared with a stored copy of to create an amplitude error. For phase compensation, the output of the phase compensator is compared with a stored copy of to create a phase error. An adaptive algorithm updates amplitude and phase errors every time so that the errors are minimized and eliminate nonlinear distortions（NLD）in the fiber-optic link.
This paper proposed that such a bidirectional radio-on DWDM transport system has been successfully demonstrated, which can interoperate with LAN and ITS applications. After 50 km transmission, good performances of BER, EVM, and IMD3/C were obtained in our proposed bidirectional radio-on DWDM transport systems. Signal qualities meet the LAN demand with a data signal of 2.4 GHz/11 Mb/s and also meet the ITS demand with a data signal of 5.8 GHz/20 Mb/s.
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