Research Of MOPA-frame 1550nm Passively Mode-locked Fiber Laser | Posted on:2012-09-22 | Degree:Master | Type:Thesis | Country:China | Candidate:P Z Liu | Full Text:PDF | GTID:2218330362460103 | Subject:Optical Engineering | Abstract/Summary: | PDF Full Text Request | Due to the eye-safe characteristic, the 1550nm short pulse laser which locates in the low-loss window of atmosphere is of great value in many applications such as optical communication, medical and remote sensing. Moreover, high power short pulse is the promising pump source for supercontinuum source (SC). Recent years, master oscillator power amplifier (MOPA) has attracted many researches because it can generate high power laser with good spectra quality and low noise. Passively mode locked fiber laser based on semiconductor saturable absorber mirror (SESAM) has become the focus of pulse laser because of the advantage such as self-starting, stable mode-locking and parameter controllable. It is the excellent seed for fiber amplifier. There are some reports focused on the high power pulse source at 1550nm but they are not all-fiber frame. In this paper, the all-fiber frame seed and two-stage amplifier of MOPA are studied. The primary contents are presented as follows:The mode-locking theory of passively mode locked fiber laser based on SESAM is introduced. The impact of EDF length, output coupler, modulation depth of SESAM and fiber dispersion on laser and the effect of dispersion-compensating fiber (DCF) in pulse compressing are studied numerically.A fiber laser passively mode-locked by SESAM in a linear cavity is experimentally demonstrated. A pulse series with 1ns width and 10.74MHz repeat frequency is achieved. The 3dB width is smaller than 0.1nm and the center wavelength is 1550nm. A maximum power about 20.5mW is generated with the optical conversation efficiency over 33%. The impact of different pump power and FBG on the laser is studied. A fiber laser passively mode-locked by SESAM in a ring cavity is experimentally demonstrated. A pulse series with 1.2ns width and 12.3MHz repeat frequency is achieved. In addition, the characteristic of the pulse with different pump power, polarization and length of the Er3+ Doped Fiber (EDF) is studied.A two-stage fiber amplifier with 22dB gain and 1.53W maximum power is designed. An EDFA is used as preamplifier and an EYDFA as power amplifier. The power and spectra characteristics with different pump power and seed power are studied. | Keywords/Search Tags: | fiber laser, fiber amplifier, master oscillator power amplifier, mode-locking, passively mode-locking, semiconductor saturable absorber mirror | PDF Full Text Request | Related items |
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