Frequency locking device based on tunable laser absorption spectrum, and frequency locking method of frequency locking device

Abstract

The invention discloses a frequency locking device based on tunable laser absorption spectrum, and a frequency locking method of the frequency locking device. The frequency locking device comprises a laser (1), an optical fiber (13), a collimation optical fiber (2), a scattered light collection lens (3), a photoelectric detector (4), a temperature and current control part (5) and a frequency stabilization part (16); particularly, the frequency stabilization part (16) comprises a lock phase amplification device (9), a data acquisition and analysis device (10), a simulation PID device (8), an operational amplifier (7), a addition device (15) and a signal generator (6) which are sequentially connected in series; according to the method, the laser is modulated by a triangle wave superposition sine wave, and the distance between two absorption peaks generated by the rising edge and the falling edge in the received scattered light signal containing gas absorption information is taken as variable value, so that a stable frequency feedback control signal is obtained, and the frequency is stabilized on the specific absorption peak. The device and the method are widely used for detecting the compositions and the contents of substances in the atmosphere by a laser spectrum technology.

Description

technical field [0001] The invention relates to a frequency locking device and a locking method, in particular to a frequency locking device and a locking method based on tunable laser absorption spectrum. Background technique [0002] With the continuous development of social economy, environmental problems have become increasingly prominent. In order to effectively monitor and predict environmental pollution, people have made unremitting efforts, trying to detect the composition and content of substances in the atmosphere through laser spectroscopy, such as Chinese invention patent specification CN 100510673 C on July 8, 2009 A laser remote sensing detection device and detection method for natural gas pipeline leakage are announced. The device described in this patent specification includes a laser connected to an optical fiber and a detector electrically connected to a control processor. The output spectrum of the laser is infrared. At the focal point of the lens, the c...

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Problems solved by technology

Although this device and its method can be used for laser remote sensing detection of natural gas pipeline leakage, there is also a problem that in actual detection applications, especially in the process of long-term continuous detection, the output frequency of the laser is extremely susceptible to changes in the external environment. For example, the influence of temperature, humidity, vibration, etc. causes the defect of frequency drift, especially the influence of the change of external environment temperature on the output frequency of the laser is particularly serious.

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