| With the emergence of 40Gbit/s communication system, increasing attention has been focused on technologies related to return-to-zero (RZ) formats. A reliable RZ light source scheme could be realized by modulating a pulse sequence of low chirp with data signals, where the key component is a stable light source generating transform-limited pulses. Superior to a conventional fiber laser, a regeneratively mode-locked fiber laser (RMLFL) operates steadily against environmental changes and could output high repetition pulse sequence with tunability both in wavelength and duration, which makes it competitive within the field of RZ light sources. When combined with pulse compression, supercontinuum generation and spectra filtering technologies, such a RMLFL is further improved to be an ideal broadband light source that could generate either multi-wavelength or wavelength tunable pulse sequence output. It can be used as an advantageous tool in experimental exploration and other applied field, including optical time division multiplexing (OTDM), optical soliton transmission, and optical measurement domain. In this dissertation, our study contents and achieved results are presented as follows, 1. Beginning with the operation principle of regeneratively mode-locking, we discuss, design and measure the basic RF components for a 10GHz RMLFL in detail. Supermode depression is realized by introducing additive pulse limiting effect using self phase modulation induced spectral spreading in dispersion shifted fiber and spectral bandpass filtering simultaneously. Principle of soliton effect in a fiber laser and the related pulse compression effect are discussed analytically. An Er3+ doped fiber amplifier which meets our requirements of the RMLFL is designed and produced successfully. 2. Studying of the start process and stable operation condition of RMLFL are accomplished. For the first time, we present and test the method of introducing polarization stable mechanism to improve system stability other than using polarization maintaining fibers, which is achieved by coiling the fiber round a small radius plate. Wavelength and duration tunable soliton output over C band is achieved in our RMLFL. During the research, we deny the feasibility of rational harmonically mode-locking in RMLFL through experimental study of its operation. The work accomplished in this section is also the innovative study reported on 10GHz RMLFL domestically. And the specification of our RMLFL equals that of the best similar RMLFLs internationally. 3. RZ format light sources based on RMLFL are realized, which quite meet the requirements of 10Gbit/s long haul transmission. Furthermore, such a 10GHz RMLFL could be upgraded to support 40Gbit/s RZ light sources simply by 4 fold OTDM. 2~6 order optical soliton phenomena are observed successfully in a dispersion flattened fiber by using our RMLFL as the soliton source, which is the first relevant report in China and one of the leading levels world-widely. Pulses with duration <2ps are achieved by using pulse compression technology, which make it feasible for our 160Gbit/s OTDM. 4. By using the amplified 10GHz, 5.5ps soliton pulses from our RMLFL as pump source, SC spectra with bandwidth of more than 50nm are acquired, covering the whole C band and part of L band. Employing spectral filtering technology, 10GHz pulse sequences with duration between 6.0~8.8ps at multiple wavelengths of C band are acquired, which is also the best result domestically.
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