Narrow-band tunable fiber laser

Abstract

The utility model discloses a narrow-band tunable fiber laser, which comprises a semiconductor amplifier, a first polarization controller, a first isolator, a fiber grating wavelength control device, a coupler, a second isolator and a second polarization controller which form a fiber resonant cavity in a fiber coupling mode. The semiconductor amplifier is used as a gain medium to amplify the laser; the first polarization controller and the second polarization controller are used for adjusting the polarization state of the polarized light; the first isolator and the second isolator are used for controlling one-way transmission of laser; the purpose of enabling the central wavelength of the fiber bragg grating to be accurate and tunable can be achieved; the coupler divides the optical signals into required ports according to the ratio and outputs the optical signals respectively, and the all-optical-fiber structure is adopted, so that the device is simpler, small in size and compact in structure.

Description

Technical Field

[0001] The utility model relates to the technical field of optical fiber lasers, in particular to a narrow-band tunable optical fiber laser. Background Art

[0002] Narrowband tunable fiber lasers offer advantages such as good coherence, flexible wavelength, and long lifespan, and have important applications in fiber-optic communications, fiber-optic sensing, and spectral analysis. As demand for these technologies increases, achieving wavelength-stable, tunable, and highly coherent fiber lasers is a hot topic in this field.

[0003] The methods for achieving laser wavelength tunability mainly include free-space mode selection and all-fiber mode selection.

[0004] Technology 1, free-space mode selection, mainly involves adding non-fiber filter devices such as FP cavity and acousto-optic filter into the laser resonant cavity. Its disadvantages are high cost, complex structure and large size.

[0005] The second technology is all-fiber mode selection, which mainly introduces a tunable fiber Bragg grating into the fiber laser resonant cavity for all-fiber laser mode selection. Among them, the technology of achieving tunability based on the strain characteristics of the fiber Bragg grating has a complex device for achieving strain, high operation difficulty, and insufficiently precise wavelength tuning.

[0006] Therefore, it is of great application value to study and realize a fiber laser with low cost, high stability, simple and compact design, and tunable wavelength range. Utility Model Content

[0007] The present utility model aims to address the deficiencies of the prior art and provide a narrowband tunable fiber laser, comprising a semiconductor amplifier, a first polarization controller, a first isolator, a fiber Bragg grating wavelength control device, a coupler, a second isolator, and a second polarization controller. Each device is coupled to a fiber optic resonant cavity by optical fiber coupling. The semiconductor amplifier serves as a gain medium to amplify the laser light. The first and second polarization controllers are used to adjust the polarization state of polarized light. The first and second isolators are used to control unidirectional transmission of the laser light. In order to achieve the purpose of accurately tunable central wavelength of the fiber Bragg grating, the coupler divides the optical signal into required ports according to a ratio and outputs them separately.

[0008] Preferably, the fiber Bragg grating wavelength control device includes a semiconductor cooler, piezoelectric ceramics, a special metal block and an insulating protective layer. The semiconductor cooler is installed at the bottom of the special metal block, and the piezoelectric ceramics are placed in the groove of the special metal block. The semiconductor cooler and the piezoelectric ceramics are controlled by a computer. The fiber Bragg grating is fixed in the upper groove of the special metal block by curing glue. The insulating protective layer wraps the part that is temperature-controlled and modulated by the semiconductor cooler.

[0009] Preferably, the special metal block is made of an elastic alloy with excellent deformation ability.

[0010] Preferably, the coupler divides the optical signal into a 10% port and a 90% port according to a ratio and outputs them separately.

[0011] Preferably, a water cooling fin is closely attached to the bottom of the semiconductor refrigerator.

[0012] Compared with the existing technology, the beneficial effects of the present invention are as follows: the present invention realizes fiber Bragg grating spectrum control by precisely controlling the temperature through a temperature control device and the stress-controlled position controlled by piezoelectric ceramics, and controls the temperature and stress of the grating, thereby precisely tuning the central wavelength of the narrow-band fiber laser to realize a narrow-band tunable fiber laser. The structure is simple and compact, the device is flexible and lightweight, the wavelength tuning range is larger, the stability is high, and it better meets the needs of actual work. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0014] Figure 1 This is the structural diagram of the utility model;

[0015] Figure 2 This is a structural diagram of the fiber Bragg grating wavelength control device.

[0016] In the figure: 1. Semiconductor amplifier; 2. First polarization controller; 3. First isolator; 4. Fiber Bragg grating wavelength control device; 5. Coupler; 6. Second isolator; 7. Second polarization controller; 8. Special metal block; 9. Piezoelectric ceramic; 10. Semiconductor refrigerator; 11. Water cooling plate; 12. Fiber Bragg grating; 13. Thermal insulation protective layer. DETAILED DESCRIPTION

[0017] The technical solution of the present invention is described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the embodiments.

[0018] Reference Figure 1 and Figure 2The utility model discloses a narrowband tunable fiber laser, a narrowband tunable fiber laser, comprising a semiconductor amplifier 1, a first polarization controller 2, a first isolator 3, a fiber Bragg grating 12 wavelength control device 4, a coupler 5, a second isolator 6, and a second polarization controller 7. Each device is connected to form a fiber resonant cavity by optical fiber coupling. The wavelength or frequency tunable function of the fiber laser resonant cavity is realized by a high-precision multi-phase-shifted fiber Bragg grating 12. The semiconductor amplifier 1 serves as a gain medium to amplify the laser; the first polarization controller 2 and the second polarization controller 7 are used to adjust the polarization state of polarized light; the first isolator 3 and the second isolator 6 are used to control the unidirectional transmission of the laser; in order to achieve the purpose of accurately tunable central wavelength of the fiber Bragg grating 12; the coupler 5 divides the optical signal into the required ports according to a ratio and outputs them separately. Here, the coupler 5 divides the optical signal into a 10% port and a 90% port according to a ratio and outputs them separately. In the present invention, the laser signal amplified by the semiconductor amplifier 1 is adjusted in polarization state by the first polarization controller 2. The output polarized light enters the multi-phase shifted fiber Bragg grating 12 module through the first isolator 3. Part of the optical signal output by the fiber Bragg grating 12 is output from the 10% port of the coupler 5, passes through the second isolator 6 and the second polarization controller 7 to enter the semiconductor amplifier 1 and circulate in the laser cavity. The other part of the light is output from the 90% port of the coupler 5 as light regulated by the filter.

[0019] The fiber Bragg grating 12 wavelength control device 4 includes a semiconductor refrigerator 10, a piezoelectric ceramic 9, a special metal block 8 and an insulating protective layer 13. The semiconductor refrigerator 10 is installed at the bottom of the special metal block 8, and the piezoelectric ceramic 9 is placed in the groove of the special metal block 8. The semiconductor refrigerator 10 and the piezoelectric ceramic 9 are controlled by a computer. The fiber Bragg grating 12 is fixed in the upper groove of the special metal block 8 by curing glue. The insulating protective layer 13 wraps the part that is temperature-controlled by the semiconductor refrigerator 10 to reduce heat dissipation and vibration. After installation, the stress and temperature of the fiber Bragg grating 12 can be adjusted according to different needs to achieve precise control of the phase shift of the fiber Bragg grating 12, and then precisely control the center wavelength of the fiber Bragg grating 12 to achieve the purpose of precise filtering.

[0020] The utility model realizes spectral control of the fiber Bragg grating 12 by precisely regulating the temperature and the stress-controlled position controlled by the piezoelectric ceramic 9 through a temperature control device. The regulation is performed from two aspects: the temperature and stress of the grating, thereby accurately tuning the central wavelength of the narrow-band fiber laser, realizing a narrow-band tunable fiber laser. The utility model has a simple and compact structure, a flexible and lightweight device, a larger wavelength tuning range, and high stability, which better meets the needs of actual work.

[0021] The special metal block 8 is made of an elastic alloy with excellent deformation ability. By changing the grating temperature and the stress it is subjected to, the wavelength of the fiber Bragg grating 12 is precisely controlled to achieve high-precision phase shift and phase shift position requirements, so that the central wavelength of the fiber Bragg grating 12 can be accurately tuned.

[0022] The bottom of the semiconductor refrigerator 10 is tightly attached to a water-cooling plate 11, which cools the semiconductor refrigerator 10 and the devices around the semiconductor refrigerator 10. The utility model adopts an all-fiber structure, which makes the device simpler, smaller and more compact. By using a semiconductor refrigerator and piezoelectric ceramics, the multi-phase-shifted fiber Bragg grating is regulated from two aspects: temperature and stress of the fiber Bragg grating, which can accurately control the central wavelength of the fiber Bragg grating to realize a tunable fiber laser, and the device is simpler and more economical.

[0023] As above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be interpreted as limiting the present invention itself. Various changes in form and details may be made without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. A narrowband tunable fiber laser, characterized by: The device comprises a semiconductor amplifier, a first polarization controller, a first isolator, a fiber Bragg grating wavelength control device, a coupler, a second isolator, and a second polarization controller. Each device is coupled to form a fiber resonant cavity through optical fiber coupling. The semiconductor amplifier serves as a gain medium to amplify the laser light. The first and second polarization controllers are used to adjust the polarization state of polarized light. The first and second isolators are used to control the unidirectional transmission of the laser light. In order to achieve the purpose of accurately tunable central wavelength of the fiber Bragg grating, the coupler divides the optical signal into required ports according to a ratio and outputs them separately.

2. The narrowband tunable fiber laser according to claim 1, characterized in that: The fiber Bragg grating wavelength control device includes a semiconductor cooler, piezoelectric ceramics, a special metal block and an insulating protective layer. The semiconductor cooler is installed at the bottom of the special metal block, and the piezoelectric ceramics are placed in the groove of the special metal block. The semiconductor cooler and the piezoelectric ceramics are controlled by a computer. The fiber Bragg grating is fixed in the upper groove of the special metal block by curing glue. The insulating protective layer wraps the part that is temperature-controlled and modulated by the semiconductor cooler.

3. The narrow-band tunable fiber laser according to claim 2, characterized in that: The special metal block is made of an elastic alloy with excellent deformation ability.

4. The narrow-band tunable fiber laser according to claim 3, characterized in that: The coupler divides the optical signal into a 10% port and a 90% port according to a ratio and outputs them respectively.

5. The narrow-band tunable fiber laser according to claim 4, characterized in that: The bottom of the semiconductor refrigerator is closely attached to a water cooling plate.

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