CN102570255A - Multi-wavelength optical fiber laser - Google Patents

Abstract

A multi-wavelength optical fiber laser relates to a laser and is suitable for the fields of optical fiber communication and sensing. The problem of poor multi-wavelength output stability and poor adjustability of output wavelengths of current multi-wavelength fiber lasers is solved. The first end (311) of the first coupler is connected to the second port of the first wavelength division multiplexer (51), and the first port of the first wavelength division multiplexer (51) is connected to the first pump source (41) , the third port of the first wavelength division multiplexer (51) is connected to one end of the first active single-mode optical fiber (11), and the other end of the first active single-mode optical fiber (11) is connected to the third end of the first coupler. end (313) to form the first single-wavelength laser, and so on, connecting the first to Nth single-wavelength lasers in series to form a multi-wavelength laser. The reflection wavelengths of the first to Nth fiber gratings (21, 22, ..., 2N) written on the first to Nth couplers are all different, and the reflection bandwidths have no overlapping parts.

Description

A multi-wavelength fiber laser

technical field

The invention relates to a laser, which is suitable for the fields of optical fiber communication and sensing.

Background technique

Multi-wavelength lasers have very important applications in the fields of optical fiber communication systems, optical fiber sensing, and spectral analysis, so they are favored by the majority of scientific and technological workers and major laser manufacturers. The dense wavelength division multiplexing technology in the communication field has greatly improved the communication capacity, and multi-wavelength lasers are indispensable equipment. Moreover, there are many types and structures of multi-wavelength fiber lasers at present, and the methods for realizing multi-wavelength output are also different.

Among them, the comb filter in the multi-wavelength laser with the comb filter as the mode selection device has different transmission or reflection ratios for different wavelength optical signals, so that the wavelength signals separated by a certain wavelength interval are filtered out, thereby producing a certain wavelength interval. The multi-wavelength laser signal output, this kind of comb filter is the most representative of the sampling grating, its working principle is that the frequency domain waveform obtained after the laser signal is Fourier transformed is in the form of a comb delta function centered on the Bragg frequency , so this grating has the property of reflecting multiple wavelengths. The difficulty in making this kind of laser lies in the poor adjustability of the comb filter. Generally, it is difficult to adjust the wavelength of the well-made filter.

The M-Z interferometer comb filter formed by two serial 3dB couplers can also be made into a multi-wavelength laser, but this type of laser has a problem, that is, the EDF is a uniform broadening medium at room temperature, and its spectrum is about 11.5nm. In the same resonant cavity, when one wavelength forms a stable oscillation, other wavelengths will be suppressed and cannot start to oscillate. At this time, the output is still a single wavelength, even if multiple wavelengths are generated sometimes, it will be very unstable.

To sum up, the multi-wavelength output stability of the current multi-wavelength fiber laser is poor, and the adjustability of each output wavelength is poor.

Contents of the invention

The technical problem to be solved by the present invention is: the multi-wavelength output stability of the current multi-wavelength fiber laser is poor, and the adjustable ability of outputting each wavelength is poor.

Technical scheme of the present invention is:

A multi-wavelength fiber laser, the laser includes: first to Nth active single-mode optical fibers, first to Nth couplers, first to Nth optical fibers respectively carved in the fusing zone of the first to Nth couplers The grating, the first to the Nth pumping source, the first to the Nth wavelength division multiplexer, the connection mode of each device is as follows:

The first port of the first coupler is connected to the second port of the first wavelength division multiplexer, the first port of the first wavelength division multiplexer is connected to the first pump source, and the third port of the first wavelength division multiplexer One end of the first active single-mode fiber is connected, and the other end of the first active single-mode fiber is connected to the third port of the first coupler to form a first single-wavelength laser.

The fourth port of the first coupler is connected to the second port of the second coupler, the first port of the second coupler is connected to the second port of the second wavelength division multiplexer, and the first port of the second wavelength division multiplexer Connect the second pumping source, the third port of the second wavelength division multiplexer is connected to one end of the second active single-mode fiber, and the other end of the second active single-mode fiber is connected to the third port of the second coupler, forming a second single wavelength laser.

...

The first port of the Nth coupler is connected to the second port of the Nth wavelength division multiplexer, the first port of the Nth wavelength division multiplexer is connected to the Nth pump source, and the third port of the Nth wavelength division multiplexer One end of the Nth active single-mode fiber is connected, and the other end of the Nth active single-mode fiber is connected to the third port of the Nth coupler to form an Nth single-wavelength laser.

The laser is output from the second port of the first coupler or/and the fourth port of the Nth coupler.

The lengths of the first to Nth fiber gratings respectively written in the first to Nth coupler fusing regions are respectively shorter than the lengths of the first to Nth coupler fusing regions, and the lengths of the first to Nth coupler fusing regions There are no grating areas at both ends of the region; the centers of the first to Nth fiber gratings do not coincide with the centers of the first to Nth coupler fusing cone regions.

When applying longitudinal tension or changing the temperature of the first to Nth fiber gratings engraved in the fusing zone of the first to Nth couplers, the wavelengths of the output laser light can be changed. The specific situation is: for the first to Nth The fiber grating applies longitudinal tension, the greater the tension, the greater the increase in wavelength; the temperature of the first to Nth fiber gratings is changed, the higher the temperature, the greater the increase in wavelength.

N is an integer of 2-100.

Compared with the prior art, the present invention has the following beneficial effects:

The laser of the present invention is composed of a plurality of single-wavelength lasers connected in series. Compared with a multi-wavelength fiber laser with a comb filter as a filter device, the optical fiber is changed by applying stress or changing the temperature of the fiber grating engraved in the fusion tapered region of the coupler. The reflection spectrum of the grating makes it possible to adjust each wavelength at will. Since the fiber grating is engraved in the fusion cone area of the coupler, the wavelengths will not interfere with each other, and the stability is strong. The power of each wavelength can be achieved by adjusting the corresponding pump power.

Description of drawings

FIG. 1 is a schematic structural diagram of a multi-wavelength fiber laser that bidirectionally outputs laser light of N wavelengths.

Fig. 2 is a schematic structural diagram of a multi-wavelength fiber laser that bidirectionally outputs two wavelengths.

Fig. 3 is a schematic structural diagram of a multi-wavelength fiber laser with a single pump outputting 50 wavelengths.

FIG. 4 is a schematic structural diagram of a multi-wavelength fiber laser that unidirectionally outputs laser light of one hundred wavelengths.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

Implementation Mode 1

A multi-wavelength fiber laser, as shown in Figure 1, the laser includes: first to Nth active single-mode optical fibers 11, 12, ..., 1N, first to Nth couplers, respectively engraved on the first to Nth The first to Nth fiber gratings 21, 22, ..., 2N of the coupler's fusing region, the first to Nth pumping sources 41, 42, ..., 4N, the first to Nth wavelength division multiplexers 51 , 52, ..., 5N, the connection method of each device is:

The first port 311 of the first coupler is connected to the second port of the first wavelength division multiplexer 51, and the first port of the first wavelength division multiplexer 51 is connected to the first pump source 41, and the first wavelength division multiplexer The third port of 51 is connected to one end of the first active single-mode fiber 11, and the other end of the first active single-mode fiber 11 is connected to the third port 313 of the first coupler to form a first single-wavelength laser.

The fourth port 314 of the first coupler is connected to the second port 322 of the second coupler, and the first port 321 of the second coupler is connected to the second port of the second wavelength division multiplexer 52, and the second wavelength division multiplexer The first port of 52 is connected to the second pumping source 42, the third port of the second wavelength division multiplexer 52 is connected to one end of the second active single-mode optical fiber 12, and the other end of the second active single-mode optical fiber 12 is connected to the second active single-mode optical fiber 12. The third port 323 of the two couplers constitutes a second single-wavelength laser.

...

The first port 3N1 of the Nth coupler is connected to the second port of the Nth wavelength division multiplexer 5N, the first port of the Nth wavelength division multiplexer 5N is connected to the Nth pumping source 4N, and the Nth wavelength division multiplexer The third port of 5N is connected to one end of the Nth active single-mode fiber 1N, and the other end of the Nth active single-mode fiber 1N is connected to the third port 3N3 of the Nth coupler to form an Nth single-wavelength laser.

The laser is output from the second port 312 of the first coupler or/and the fourth port 3N4 of the Nth coupler.

The lengths of the first to Nth fiber gratings 21, 22, ..., 2N respectively written in the first to Nth coupler fusing regions are respectively shorter than the lengths of the first to Nth coupler fusing regions, and at the Both ends of the first to the Nth coupler's fusing region have areas without gratings; the centers of the first to the Nth fiber gratings 21, 22, ..., 2N are not the same as the centers of the first to the Nth coupler's fusing region coincide.

The reflection wavelengths of the first to the Nth fiber gratings respectively written on the first to the Nth couplers are all different, and the reflection bandwidths have no overlapping parts.

When applying longitudinal stress or changing the temperature of the first to Nth fiber gratings engraved in the fusing zone of the first to Nth couplers, the wavelengths of the output laser light can be changed. The specific situation is: for the first to Nth The fiber grating applies longitudinal tension, the greater the tension, the greater the increase in wavelength; the temperature of the first to Nth fiber gratings is changed, the higher the temperature, the greater the increase in wavelength.

N is an integer of 2-100.

Implementation mode two

A multi-wavelength fiber laser, as shown in Figure 2, the laser includes: first and second active single-mode optical fibers 11, 12, first and second couplers, respectively engraved on the first and second coupler fusion cone regions The first and second fiber gratings 21 and 22, the first and second pumping sources 41 and 42, the first and second wavelength division multiplexers 51 and 52, and the connection methods of each device are as follows:

The first port 311 of the first coupler is connected to the second port of the first wavelength division multiplexer 51, and the first port of the first wavelength division multiplexer 51 is connected to the first pump source 41, and the first wavelength division multiplexer The third port of 51 is connected to one end of the first active single-mode optical fiber 11, and the other end of the first active single-mode optical fiber 11 is connected to the third port 313 of the first coupler.

The fourth port 314 of the first coupler is connected to the second port 322 of the second coupler, and the first port 321 of the second coupler is connected to the second port of the second wavelength division multiplexer 52, and the second wavelength division multiplexer The first port of 52 is connected to the second pumping source 42, the third port of the second wavelength division multiplexer 52 is connected to one end of the second active single-mode optical fiber 12, and the other end of the second active single-mode optical fiber 12 is connected to the second active single-mode optical fiber 12. The third port 323 of the second coupler.

The laser light is output from the second port 312 of the first coupler or/and the fourth port 324 of the second coupler.

The lengths of the first and second fiber gratings 21 and 22 respectively written in the fusing regions of the first and second couplers are respectively shorter than the lengths of the fusing regions of the first and second couplers, and in the first and second coupling Both ends of the fuser region of the coupler have areas without gratings; the centers of the first and second fiber gratings 21 and 22 do not coincide with the centers of the first and second coupler’s fuser regions.

The reflection wavelengths of the first and second optical fiber gratings respectively written on the first and second couplers are different, and the reflection bandwidths have no overlap.

The reflection bandwidth of the fifty-first fiber grating is the range from the shortest wavelength in the reflection spectra of the first and second fiber gratings to the longest wavelength in the reflection spectra of the first and second fiber gratings.

Applying longitudinal stress or changing the temperature of the first and second fiber gratings engraved in the fusing region of the first and second couplers can change the wavelengths of the output laser light. The specific situation is: for the first and second optical fibers A longitudinal tension is applied to the grating, and the greater the tension, the greater the increase in wavelength; the temperature of the first and second fiber gratings is changed, and the higher the temperature, the greater the increase in wavelength.

Implementation Mode Three

A multi-wavelength fiber laser, as shown in Figure 3, the laser includes: first to fiftieth active single-mode optical fibers 11, 12, ..., 150, first to fiftieth couplers, respectively engraved on the first to fiftieth The first to fiftieth fiber gratings 21, 22, ..., 250 in the fusing zone of the fiftieth coupler, the fifty-first fiber grating 251, the first pumping source 41, and the connection methods of each device are as follows:

The first pump source 41 is connected to one end of the fifty-first fiber grating 251, the other end of the fifty-first fiber grating 251 is connected to the second port 312 of the first coupler, and the first port 311 of the first coupler is connected to the first port 312 of the first coupler. The active single-mode fiber 11, the other end of the first active single-mode fiber 11 is connected to the third port 313 of the first coupler.

The fourth port 314 of the first coupler is connected to the second port 322 of the second coupler, the first port 321 of the second coupler is connected to one end of the second active single-mode optical fiber 12, and the second active single-mode optical fiber 12 The other end is connected to the third port 323 of the second coupler.

...

The first port 3501 of the fiftieth coupler is connected to one end of the first active single-mode fiber 150, and the other end of the first active single-mode fiber 150 is connected to the third port 3503 of the fiftieth coupler.

Laser light is output from the fourth port 3504 of the fiftieth coupler.

The lengths of the first to fiftieth fiber gratings 21, 22, ..., 250 respectively written in the fusing regions of the first to fiftieth couplers are respectively shorter than the lengths of the fusing regions of the first to fiftieth couplers, And there are areas without gratings at both ends of the first to fiftieth coupler fusion cone regions; The centers of the fusion cones do not coincide.

The reflection wavelengths of the first to fiftieth fiber gratings respectively written on the first to fiftieth couplers are all different, and the reflection bandwidths have no overlap.

Applying longitudinal stress or changing the temperature of the first to fiftieth fiber gratings engraved in the fusing zone of the first to fiftieth couplers can change the wavelengths of the output laser light. The specific situation is: for the first to the fiftieth Fifty fiber gratings apply longitudinal tension, the greater the tension, the greater the increase in wavelength; the temperature of the first to fiftieth fiber gratings is changed, the higher the temperature, the greater the increase in wavelength.

Implementation Mode Four

A multi-wavelength fiber laser, as shown in Figure 4, the laser includes: the first to the hundredth active single-mode optical fibers 11, 12, ..., 1100, the first to the hundredth couplers, respectively engraved on the first to the hundredth The first to the hundredth fiber gratings 21, 22, ..., 2100 of the fusion zone of the hundredth coupler, the one hundred and first fiber grating 2101, the first to the hundredth pump sources 41, 42, ... , 4100, the first to the hundredth wavelength division multiplexer 51, 52, ..., 5100, the connection mode of each device is:

The second port 312 of the first coupler is connected to the one hundred and first fiber grating 2101, the first port 311 of the first coupler is connected to the second port of the first wavelength division multiplexer 51, and the first wavelength division multiplexer 51 The first port of the first active single-mode optical fiber 11 is connected to the first pump source 41, the third port of the first wavelength division multiplexer 51 is connected to one end of the first active single-mode optical fiber 11, and the other end of the first active single-mode optical fiber 11 is connected to the first active single-mode optical fiber 11. The third port 313 of the coupler.

The fourth port 314 of the first coupler is connected to the second port 322 of the second coupler, and the first port 321 of the second coupler is connected to the second port of the second wavelength division multiplexer 52, and the second wavelength division multiplexer The first port of 52 is connected to the second pumping source 42, the third port of the second wavelength division multiplexer 52 is connected to one end of the second active single-mode optical fiber 12, and the other end of the second active single-mode optical fiber 12 is connected to the second active single-mode optical fiber 12. The third port 323 of the second coupler.

...

The first port 31001 of the one hundredth coupler is connected to the second port of the one hundredth wavelength division multiplexer 5100, the first port of the one hundredth wavelength division multiplexer 5100 is connected to the one hundredth pump source 4100, the one hundredth The third port of the wavelength division multiplexer 5100 is connected to one end of the hundredth active single-mode fiber 1100, and the other end of the hundredth active single-mode fiber 1100 is connected to the third port 31003 of the hundredth coupler.

Laser light is output from the fourth port 31004 of the hundredth coupler.

The lengths of the first to the hundredth fiber gratings 21, 22, ..., 2100 written in the fusing regions of the first to the hundredth couplers respectively are less than the lengths of the fusing regions of the first to the hundredth couplers, And there are areas without gratings at both ends of the fusing cone region of the first to the hundredth coupler; The centers of the fusion cones do not coincide.

The reflection wavelengths of the first to the hundredth fiber gratings respectively written on the first to the hundredth couplers are all different, and the reflection bandwidths have no overlap.

Applying longitudinal stress or changing the temperature of the first to the hundredth fiber gratings engraved in the first to the hundredth coupler's fusing zone can change the wavelengths of the output laser light, the specific situation is: for the first to the hundredth One hundred fiber gratings apply longitudinal tension, the greater the tension, the greater the increase in wavelength; the temperature of the first to the hundredth fiber gratings is changed, the higher the temperature, the greater the increase in wavelength.

Claims (5)

1. A multi-wavelength fiber laser, characterized in that: the laser comprises the first to the Nth active single-mode fiber (11, 12, ..., 1N), the first to the Nth coupler, respectively engraved on the first The first to Nth fiber gratings (21, 22, ..., 2N) to the Nth coupler fusing region, the first to Nth pumping sources (41, 42, ..., 4N), the first to the first N wavelength division multiplexer (51, 52, ..., 5N), the connection mode of each device is: The first port (311) of the first coupler is connected to the second port of the first wavelength division multiplexer (51), and the first port of the first wavelength division multiplexer (51) is connected to the first pump source (41) , the third port of the first wavelength division multiplexer (51) is connected to one end of the first active single-mode optical fiber (11), and the other end of the first active single-mode optical fiber (11) is connected to the third end of the first coupler. port (313), forming the first single-wavelength laser; The fourth port (314) of the first coupler is connected to the second port (322) of the second coupler, and the first port (321) of the second coupler is connected to the second port of the second wavelength division multiplexer (52) , the first port of the second wavelength division multiplexer (52) is connected to the second pumping source (42), and the third port of the second wavelength division multiplexer (52) is connected to the second active single-mode optical fiber (12) One end of the second active single-mode optical fiber (12) is connected to the third port (323) of the second coupler at the other end to form a second single-wavelength laser; ... The first port (3N1) of the Nth coupler is connected to the second port of the Nth wavelength division multiplexer (5N), and the first port of the Nth wavelength division multiplexer (5N) is connected to the Nth pumping source (4N) , the third port of the Nth wavelength division multiplexer (5N) is connected to one end of the Nth active single-mode fiber (1N), and the other end of the Nth active single-mode fiber (1N) is connected to the third end of the Nth coupler The port (3N3) constitutes the Nth single-wavelength laser; The laser is output from the second port (312) of the first coupler or/and the fourth port (3N4) of the Nth coupler; The lengths of the first to Nth fiber gratings (21, 22, ..., 2N) respectively written in the first to Nth coupler fusion cone regions are respectively shorter than the lengths of the first to Nth coupler fusion cone regions, and There are areas without gratings at both ends of the first to Nth coupler fusion cone regions; the centers of the first to Nth fiber gratings (21, 22, ..., 2N) and the first to Nth coupler fusion cones District centers do not overlap; N is an integer of 2-100. 2. A kind of multi-wavelength fiber laser according to claim 1, characterized in that: The reflection wavelengths of the first to Nth fiber gratings (21, 22, ..., 2N) written on the first to Nth couplers are all different, and the reflection bandwidths have no overlapping parts. 3. A kind of multi-wavelength fiber laser according to claim 1, characterized in that: The first pumping source (41) is connected to the second port (312) of the first coupler via the N+1th fiber grating (2(N+1)), and the first port (311) of the first coupler is connected to the second port (311) of the first coupler. One end of an active single-mode optical fiber (11); The first port (321) of the second coupler is connected to one end of the second active single-mode optical fiber (12); ... The first port (3N1) of the Nth coupler is connected to one end of the Nth active single-mode optical fiber (1N); The laser is output from the fourth port (3N4) of the Nth coupler; The reflection bandwidth of the N+1 fiber Bragg grating (2(N+1)) is from the shortest wavelength in the reflection spectrum of the first to N fiber Bragg gratings (21, 22, ..., 2N) to the first to N fiber Bragg gratings (21, 22, ..., 2N) The wavelength range of the longest wavelength in the reflection spectrum. 4. A kind of multi-wavelength fiber laser according to claim 1, characterized in that: The second port (312) of the first coupler is connected to the N+1th fiber grating (2(N+1)). 5. A kind of multi-wavelength fiber laser according to claim 1, 3 or 4, characterized in that: When applying longitudinal tension or changing the temperature of the first to Nth fiber gratings (21, 22, ..., 2N) carved in the first to Nth coupler fusing cone regions, the output wavelength of the laser is changed.

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