Full optical fiber laser Raman proving installation
Technical field
The invention belongs to the laser measurement field, relate to a kind of full optical fiber laser Raman Measurement device.
Background technology
The laser raman technology has been widely used in the various fields such as biology, medical science, food, scientific research.In the present laser raman device, light source adopts solid state laser and semiconductor laser more, and the light channel structure design mainly contains two kinds:
(1) transmission of exploring laser light, emission and flashlight is received as the space optical path structure.This system adopts optical element to come transmission and the emission of exploring laser light are controlled, and the flashlight that returns is collected by optical receiving system after the mating plate after filtration and enters detector.This system adopts a large amount of mechanical speed-control device and optical elements to cause system bulk numerous and jumbled, has caused inevitably whole stability decreases simultaneously;
(2) on the basis of said structure, adopt optical fiber to substitute space optical path, by coupling device exploring laser light being coupled into optical fiber transmits, shine on the target through behind the emitter, by receiving trap flashlight is coupled into optical fiber, measures to detector by Optical Fiber Transmission after the mating plate after filtration.This structure will be finished in optical fiber in the Laser Transmission process in space originally, segment space mechanical structured member and optical element have been reduced, improved stability, but increased the device that laser coupled enters optical fiber, and transmitting and receiving of system still is discrete optical system, need the optical fiber more than 2, structure aspects is still succinct not, stable.
Sum up above-mentioned two kinds of light channel structures, its common characteristics are to transmit and receive to adopt discrete light path, at the receiving light path of flashlight optical filter is set and remnants is surveyed the mechanical speed-control device that complexity and less stable are arranged on light filtering, the light path.
Summary of the invention
In order to solve the above-mentioned technical matters that exists in the background technology, the invention provides a kind of good stability, volume full optical fiber laser Raman proving installation little and simple in structure.
Technical solution of the present invention is: the invention provides a kind of full optical fiber laser Raman proving installation, its special character is: described full optical fiber laser Raman proving installation comprises light source, fibre optic isolater, wave division multiplex coupler, doubly clad optical fiber, emitting/receiving and spectroanalysis instrument; Described fibre optic isolater is arranged on the emitting light path of light source; Described fibre optic isolater and spectroanalysis instrument are respectively by wave division multiplex coupler and doubly clad optical fiber access emitting/receiving; Target to be measured is arranged on the emitting light path of emitting/receiving.
Above-mentioned light source is by optical fiber incoming fiber optic isolator.
Above-mentioned light source is the semiconductor laser of fiber laser, coupling fiber output or the various laser instruments of commonly using at optical field.
Advantage of the present invention is:
Utilize doubly clad optical fiber as Transmission Fibers among the present invention, the optical fiber of the type has two coverings, and the passage that passes light comprises fibre core and inner cladding: core diameter is thin, numerical aperture is less, and the inner cladding diameter is thick, numerical aperture is larger.According to the characteristics of doubly clad optical fiber, the core diameter value of counting accurately aperture is little, adopts fibre core transmission exploring laser light can guarantee its preferably zlasing mode; The thick numerical aperture of inner cladding diameter is large, can receive and transmit the more scattered light signal of large aperture angle, is used for transmitting Raman signal light.In the fibre core in exploring laser light and the inner cladding transmission direction of signal laser be opposite in doubly clad optical fiber, share an optical fiber, and do not disturb each other.When both fully having satisfied the transmission of exploring laser light and flashlight, the present invention to the requirement of optical fiber, again two light paths were combined by an optical fiber; All optical fibre structure, volume is little, and stability is high, exempts from debugging, and is non-maintaining; The present invention adopts doubly clad optical fiber, has realized the common Optical Fiber Transmission of exploring laser light and flashlight, has greatly simplified the structure of system; Simultaneously, pattern preferably exploring laser light constrains in the fibre core transmission, has kept preferably zlasing mode, and the Raman signal light of scattering is received in the inner cladding that is coupled to multimode and transmits, and can receive more flashlight; Adopt the doubly clad optical fiber wavelength division multiplexer, do not use optical filter also to realize filter function.Structure provided by the present invention is all optical fibre structure, transmitting-receiving altogether light path, the laser raman proving installation that do not adopt optical filter to filter, has solved the problems such as complex structure in the background technology, bulky, poor stability.
Description of drawings
Fig. 1 is the structural representation of doubly clad optical fiber of the present invention;
Fig. 2 is full optical fiber laser Raman proving installation structural representation provided by the present invention;
The 1-light source; The 2-fibre optic isolater; The 3-wave division multiplex coupler; The 4-doubly clad optical fiber; The 5-emitting/receiving; 6-target to be measured; The 7-spectroanalysis instrument.
Embodiment
Gordian technique among the present invention is to have utilized cleverly doubly clad optical fiber as Transmission Fibers.As shown in Figure 1, the optical fiber of the type has two coverings, and the passage that passes light comprises fibre core and inner cladding: core diameter is thin, numerical aperture is less; The inner cladding diameter is thick, numerical aperture is larger.According to the characteristics of doubly clad optical fiber, core diameter is thin, numerical aperture is little, adopts fibre core transmission exploring laser light can guarantee its preferably zlasing mode; The thick numerical aperture of inner cladding diameter is large, can receive and transmit the more scattered light signal of large aperture angle, is used for transmitting Raman signal light.In the fibre core in exploring laser light and the inner cladding transmission direction of signal laser be opposite in doubly clad optical fiber, share an optical fiber, and do not disturb each other.The ingenious part of this thinking is: to the requirement of optical fiber, again two light paths are combined by an optical fiber when both fully having satisfied the transmission of exploring laser light and flashlight.
Referring to Fig. 2, the invention provides a kind of full optical fiber laser Raman proving installation, this full optical fiber laser Raman proving installation comprises light source, fibre optic isolater, wave division multiplex coupler, doubly clad optical fiber, emitting/receiving and spectroanalysis instrument; Fibre optic isolater is arranged on the emitting light path of light source; Fibre optic isolater and spectroanalysis instrument are respectively by wave division multiplex coupler and doubly clad optical fiber access emitting/receiving; Target to be measured is arranged on the emitting light path of emitting/receiving.Emitting/receiving 5 and wave division multiplex coupler 3 are accessed respectively in the doubly clad optical fiber two ends; Target to be measured is arranged on the emitting light path of emitting/receiving 5.
The course of work of the present invention is: exploring laser light light source 1 adopts fiber laser or the semiconductor laser of coupling fiber output or the laser instrument of other type; be connected with fibre optic isolater 2 by optical fiber, the laser that the effect of fibre optic isolater 2 is to return is every living with protection light source 1.Enter doubly clad optical fiber wave division multiplex coupler 3 by the exploring laser light behind the fibre optic isolater 2, the effect of wave division multiplex coupler 3 is and different wave length can be coupled, different wave length can be separated conversely.Exploring laser light enters in the fibre core of doubly clad optical fiber 4 by behind the wave division multiplex coupler 3, and transmission is by behind the optical fiber emitting/receiving 5 forward, and collimation/focusing is radiated on the target 6 to be measured, produces the Raman signal light of scattering.Raman signal light is collected by emitting/receiving 5, because flashlight is scattered light, most of optically-coupled of therefore collecting has entered in the inner cladding of doubly clad optical fiber, reverse transfer is to wave division multiplex coupler 3, because Raman signal light wavelength and exploring laser light is different, therefore export to the high sensitivity spectroanalysis instrument 7 from the b port by wave division multiplex coupler 3 rear flashlights signal data is analyzed out, remaining exploring laser light then from the output of a port, is isolated by fibre optic isolater 2.