Shipborne expendable optical-fiber bathythermograph

Abstract

A shipborne expendable optical-fiber bathythermograph comprises an all optical fiber probe, transmission optical fibers and a deck unit, wherein the probe measures the seawater temperature through LPG (long period fiber gratings) and measures the seawater depth through FBG (fiber bragg gratings), and seawater temperature and depth profiles are measured independently at high sensitivity; the deck unit comprises a broadband light source, a dynamic fiber grating fast and high-precision demodulation module, an optical fiber isolator, a first optical fiber coupler, a second optical fiber coupler, an upper fiber shaft and a telescopic support mounted on the board of the stem of a working ship. The thermograph solves the problems of cross sensitivity and sensitization of a sensor, the sensitivity of temperature and depth measurement is improved, errors caused by enameled wire channels are overcome, the signal transmission rate and the stability are guaranteed, single light path cascade of FBG and LPG is realized, a light path structure is optimized, the spectral region is allocated reasonably, temperature and depth synchronous detection is realized, the thermograph is simple to manufacture, the probe is low in cost, and a new technical means is provided for detection of the seawater temperature and depth profiles.

Description

technical field [0001] The invention relates to a seawater temperature and depth profile measurement system, in particular to a ship-borne throw-away all-optical seawater temperature and depth profile measurement system. Background technique [0002] Expendable Bathy Thermograph (XBT) is an important instrument for ocean temperature and depth measurement. It is of great significance to the obtained ocean hydrological data for climate change, physical oceanography and military research. focus on. However, the traditional XBT depth data is not the result of accurate measurement, and because the transmission channel uses enameled wire as the transmission medium, which itself is similar to a dynamic filtering system, the transmission rate and transmission accuracy of the system are greatly limited. [0003] The fiber grating sensor is a sensor that uses the principle that the central wavelength of the fiber grating has a certain functional relationship with the external environ...

AI Technical Summary

Problems solved by technology

However, in practical applications, the volume and weight of fiber optic XBT probes are strictly limited, and the available space for the lower fiber shaft integrated in the probe is very limited. It is required that the transmission fibers be wound together as compactly as possible, which will greatly The increase in the transmission loss of the fiber shaft part of the fiber

None of the previous studies considered the effect of tight winding on data transmission

[0006] To sum up, the traditional XBT method has the disadvantages of inaccurate depth data measurement, the channel is susceptible to external interference, and large system deviation; the existing optical fiber XBT method has too low temperature sensitivity to meet the needs of ocean observation, so there is an urgent need for a A new technology that can not only meet the monitoring needs of ocean temperature and depth profiles, but also overcome the shortcomings of existing XBT methods

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