CN101769819B - Optical Fiber Dispersion Measuring Instrument - Google Patents

Abstract

An optical fiber dispersion measuring instrument, the instrument comprises: a broadband light source input port, an optical fiber coupler arranged at the output end of the broadband light source input port; a collimator arranged at the output end of the fiber coupler connected by an optical fiber; arranged at the output end of the collimator The first reflector, the second reflector, the third reflector, the fourth reflector, the tenth reflector, the fifth reflector, and the sixth reflector are arranged in sequence along the optical path; The optical fiber adapter, optical fiber adapter, microscope objective lens and the twelfth reflector for the secondary connection; the electric translation stage arranged at the lower end of the third reflector and the fourth reflector, and the control port of the electric translation stage; the instrument also includes a The output end of the optical fiber coupler after interference is connected to the interference light output port through the optical fiber; the invention solves the technical problems of low measurement accuracy and high measurement cost in the prior art. The invention has the advantages of simple structure, low price, high detection efficiency and the like.

Description

Optical Fiber Dispersion Measuring Instrument

technical field

The invention relates to the field of optical fiber measurement, in particular to an optical fiber dispersion measuring instrument.

Background technique

Fiber dispersion is a very important physical quantity to describe the characteristics of fiber optic materials, especially the generation, amplification and transmission characteristics of ultrashort pulse laser in fiber optics, and the quality of information transmission of light waves in fiber optic communication devices. Therefore, accurate measurement of fiber dispersion is an important basis for the design of fiber laser devices and communication devices. At present, the optical fiber dispersion measurement methods used by various industrial laboratories and research institutions mainly include time delay method, phase shift method, mode field diameter method and interferometry. The use of the delay method requires a long length of optical fiber to be tested, generally more than 0.5km, and the measurement accuracy is low, and the time resolution is only 50ps; the phase shift method requires a tunable light source with high signal-to-noise ratio and high adjustment accuracy, resulting in measurement costs Too high; the mode field diameter method needs to measure the material dispersion value of the optical fiber separately to indirectly obtain its total dispersion.

Contents of the invention

The object of the present invention is to provide an optical fiber dispersion measuring instrument, which solves the technical problems of low measurement accuracy and high measurement cost in the background art.

Technical scheme of the present invention is:

A fiber optic dispersion measuring instrument, the instrument comprising: a broadband light source input port 1, an optical fiber coupler 2 arranged at the output end of the broadband light source input port 1; a collimator 3 arranged at the output end of the fiber coupler 2 connected through an optical fiber 201; The first reflector 401, the second reflector 402, the third reflector 403, the fourth reflector 404, the tenth reflector 410, the fifth reflector 405, the sixth Reflector 406; the motorized translation stage 5 arranged at the lower end of the third reflector 403 and the fourth reflector 404 controls the port 501 with the motorized translation stage; Connected interference light output port 9; and microscope objective lens 6, the twelfth reflecting mirror 412; It is characterized in that: the eleventh reflecting mirror 411, the seventh reflecting mirror 411, the seventh reflecting mirror 412 are also arranged successively on the reflected light path of the sixth reflecting mirror 406 mirror 407, the eighth reflector 408, the ninth reflector 409; the output end of the fiber coupler 2 is provided with a first fiber optic adapter 701, and a polarization In the controller 8 , an optical fiber adapter 702 is provided at the output end of the twelfth reflecting mirror 412 .

The sixth reflector 406 is further provided with an eleventh reflector 411 , a seventh reflector 407 , an eighth reflector 408 , and a ninth reflector 409 along the reflection optical path in sequence;

A polarization controller 8 is further arranged between the output end of the fiber coupler 2 and the fiber adapter 701 .

The third reflecting mirror 403 , the fourth reflecting mirror 404 , the tenth reflecting mirror 410 and the eleventh reflecting mirror 411 are movable reflecting mirrors.

The above broadband light source input port 1 is a standard FC/PC pluggable optical fiber interface.

The advantages of the present invention are:

The time resolution of dispersion measurement by fiber optic dispersion measuring instrument and interferometry is as high as 0.1 ps. The optical path is an all-fiber structure, and only short optical fibers are needed to meet the measurement requirements; the measurement method is simple, fast, cheap, and the detection efficiency is relatively high; optical fiber The structure of the dispersion measuring instrument is also relatively simple.

Description of drawings:

FIG. 1 is a schematic structural diagram of a dispersion measurement device of the present invention.

Reference signs:

1-broadband light source; 2-fiber coupler; 3-fiber collimator; 4-reflection device, 401-first reflector, 402-second reflector, 403-third reflector, 404-fourth reflector , 405-fifth reflector, 406-sixth reflector, 407-seventh reflector, 408-eighth reflector, 409-ninth reflector, 410-tenth reflector, 411-eleventh reflector , 412—twelfth reflection mirror; 5—translation stage; 6—microscopic objective lens; 7—fiber adjustment frame; 8—polarization controller; 9—interfering light output port;

Detailed ways:

See Figure 1

An optical fiber dispersion measuring instrument comprises: a broadband light source input port 1, the broadband light source input port 1 being a standard FC/PC pluggable optical fiber interface. The fiber coupler 2 arranged at the output end of the broadband light source input port 1; the collimator 3 arranged at the output end of the fiber coupler 2 connected through the optical fiber 201; the first reflector 401 arranged at the output end of the collimator 3 along the optical path in sequence , the second reflector 402, the third reflector 403, the fourth reflector 404, the tenth reflector 410, the fifth reflector 405, the sixth reflector 406; the sixth reflector 406 is also arranged in turn along the reflection optical path There are the eleventh reflector 411, the seventh reflector 407, the eighth reflector 408, and the ninth reflector 409; the optical fiber adapter 701, the optical fiber adapter 702, the microscopic The objective lens 6 and the twelfth reflector 412, a polarization controller 8 is also arranged between the output end of the fiber coupler 2 and the fiber adapter 701; the electric translation stage 5 arranged at the lower end of the third reflector 403 and the fourth reflector 404 And the electric translation platform control port 501; the third reflector 403, the fourth reflector 404, the tenth reflector 410 and the eleventh reflector 411 are movable reflectors; After the output end is connected to the interference light output port 9 via an optical fiber.

It works as follows:

(i) Input the light source through the input port 1 of the broadband light source, and connect the output broadband light source into the fiber coupler 2 via the optical fiber 101 .

(ii), light source beam splitting: the fiber coupler 2 splits the output light of the broadband light source to form a spatial optical path 201 and an optical path 202; the optical path 201 is a spatial propagation light, and its light field propagates in the air without dispersion. time delay. The spatial reference light is reflected and folded by the first reflector 401 and the second reflector 402 on the propagation path, is incident on the third reflector 403 arranged on the electric translation stage 5, and is transmitted by the fourth reflector 404, the tenth reflector 410, the fifth reflector 405, the sixth reflector 406, the eleventh reflector 411, the seventh reflector 407, and the eighth reflector 408 are sequentially reflected until the ninth reflector 409, and the ninth reflector 409 reflects the light beam vertically back. The tenth reflector 410 and the eleventh reflector 411 are movable reflectors, which can cut into the optical path at any time and reflect the light beam back to the original path, so as to change the spatial optical path. The third reflector 403 and the fourth reflector 404 on the motorized translation stage 5 can move along with the translation stage to change the spatial optical path, but the beams reflected by them are always on the same optical path. In the measurement optical path 202 , the output beam collimated by the optical fiber 10 to be tested is reflected back to the optical fiber by the twelfth reflector 412 . The optical fiber 10 to be tested is connected to the measurement optical path through the FC/PC optical fiber adapter. Fiber, etc. can be clamped on the corresponding bare fiber adapter and then connected to the measurement optical path. The measured waveband can be changed by changing the broadband light source. Using the ytterbium ion A S E light source can measure the dispersion value in the 1030nm-1080nm spectral range; using the erbium ion A S E light source can also measure the dispersion value in the 1530nm-1580nm spectral range. If it is necessary to measure the dispersion value of other bands, just replace the broadband light source of the corresponding band. At the beginning of the measurement, first estimate the optical path according to the length of the optical fiber to be measured, check which spatial optical path interval it belongs to according to the estimated value, and then select the corresponding mirror to form the spatial optical path. Adjust the mirrors of the reference light path and the measurement light path so that the beams are efficiently reflected back to the 50:50 fiber coupler. Connect the pigtail 901 to the spectrometer, observe the interference spectrum pattern from the spectrometer, and adjust the polarization controller until the contrast of the interference fringes is maximum. Read the spectral data from the computer connected with the spectrometer, fit the spectral curve with software, select the best fitting parameters, and obtain the dispersion value of the optical fiber.

(iii), output light source: the optical fiber output by fiber coupler 2 is output by fiber collimator 3 as reference light along the spatial optical path 201; along the optical path 202, it enters the optical fiber to be measured through the polarization controller 8, and the optical fiber to be measured passes through the optical fiber adapter 7 along the optical path 202 The light path enters the microscope objective lens 6 and enters the reflector 412;

(iv) Optical path switching: the spatial optical path 201 switches the spatial optical path through the movable broadband reflection system 4 to realize the measurement of optical fibers in different length intervals.

(v), light field return: the spatial optical path 201 and the optical path 202 return along the original path, enter the fiber coupler 2 again and interfere, which is equivalent to a Michelson interferometer, and the interference fringes are at wavelengths at equal optical paths The wavelength bands expand symmetrically from the center to both sides, showing periodic intensity fluctuations, and the interference spectrum is input to the spectrometer through the output end of the coupler for detection.

(vi) Adjusting the optical path: adjusting the optical path of the spatial reference light so that it can be equal to a certain wavelength of the measuring light after dispersion.

(vii) Determine the dispersion value: when the interference spectrum pattern centered on a certain wavelength is measured, the spectrum is numerically fitted and compared with the dispersion equation to obtain the dispersion value of the optical fiber.

Claims (4)

1. A kind of optical fiber dispersion measuring instrument, this instrument comprises: broadband light source input port (1), is arranged on the fiber optic coupler (2) of broadband light source input port (1) output end; Be arranged on fiber optic coupler (2) output end through A collimator (3) connected to the optical fiber (201); a first reflector (401), a second reflector (402), and a third reflector (403) arranged in sequence along the optical path at the exit end of the collimator (3) ), the fourth reflector (404), the tenth reflector (410), the fifth reflector (405), the sixth reflector (406); the third reflector (403) and the fourth reflector (404) ) at the lower end of the electric translation stage (5) and the electric translation stage control port (501); the instrument also includes an interference light output port (9) connected by an optical fiber at the output end of the optical fiber coupler (2) after the interference occurs; And the twelfth reflecting mirror (412), the microscopic objective lens (6) that is arranged on the upper end of the twelfth reflecting mirror (412); it is characterized in that: the reflection optical path of the described sixth reflecting mirror (406) is also provided with The eleventh reflector (411), the seventh reflector (407), the eighth reflector (408), the ninth reflector (409); the output end of the fiber coupler (2) is provided with a first optical fiber adapter (701), a polarization controller (8) is arranged between the output end of the optical fiber coupler (2) and the first optical fiber adapter (701), and a second optical fiber adapter is arranged at the output end of the microscope objective lens (6) (702). 2. The optical fiber dispersion measuring instrument according to claim 1, characterized in that: the third reflector (403), the fourth reflector (404), the tenth reflector (410) and the eleventh reflector ( 411) is a movable reflector. 3. The optical fiber dispersion measuring instrument according to claim 1 or 2, characterized in that: the broadband light source input port (1) is an FC/PC pluggable optical fiber interface. 4. The optical fiber dispersion measuring instrument according to claim 3, characterized in that: the first optical fiber adapter (701) and the second optical fiber adapter (702) are FC/PC pluggable optical fiber interfaces. the

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