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Power Stabilization Of Medium Wave Infrared Laser Using Acousto-optic Modulation

Posted on:2015-10-03Degree:MasterType:Thesis
Country:ChinaCandidate:Z K DingFull Text:PDF
GTID:2308330464966744Subject:Electronics and Communications Engineering
Abstract/Summary:PDF Full Text Request
In the precision optical radiation measurement, the cryogenic absolute radiometer plays an important role in improving spectral radiation measurement precision. The invention of cryogenic absolute radiometer make optical radiation measurement reach unprecedented high accuracy. and gives a higher request to laser. Both the laser power’s and the cryogenic absolute radiometer’s stabilization depend on mutual authentication with one another. But for the output power of general laser, it is easy to be affected by the internal conditions, which are the power supply’s current fluctuation, the laser’s mode jump, the spontaneous emission, the active medium’s gain coefficient, etc. In addition, the external environment is also important factor, which makes us get the stability of light intensity with difficulty. By testing, there are about 10% fluctuations for the common medium wave infrared laser within an hour. For the precision optical radiation measurement, the stabilized light intensity is urgent. Therefore, a kind of technology for stabilizing the MWIR laser’s power is came out and a system is built.Firstly, against the deficiency of the technology in existence, this essay introduces the development of the laser light intensity stabilization technology at home and abroad. The working principle of the MWIR laser is described as followed. As an example, the reason that the He-Ne laser’s output power fluctuations is explained. Then, the principles and methods of laser power stabilization technology are presented with outside control. Based on the technology of acousto-optic modulation, the MWIR laser power stabilization system is designed, which covers optical system, acousto-optical modulator, control circuit and machine construction, et al. The optic noises can be eliminated effectively when MWIR laser pass the optical system. Both the photoelectric conversion module and the feedback control module are important control circuits. For the optoelectronic conversion module, it will transform the MWIR laser into the electrical signal and amplifies it for the further processing. For the feedback control module, it will convert analog signals to digital ones and form the feedback signals finally. Moreover, the test results are deeply analyzed with different experimental conditions, which are the system open time, the laser preheating time, detector working temperature and the environment, et al. The experimental results show that the system has the advantages of good controllability, less noise, stability and high precision, and it is an effective method for the high precision system.Using acousto-optic modulation, the MWIR laser power stabilization system has been researched and developed in this thesis, which has good engineering value.
Keywords/Search Tags:cryogenic absolute radiometer, MWIR, laser power stabilization, acousto-optical modulation, feedback control
PDF Full Text Request
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