A tuning device for fiber grating

Abstract

The present invention provides a tuning device for a fiber grating, comprising a housing, a chirped fiber grating, a heat conducting plate, at least five temperature control components and a main control circuit board, wherein the housing is provided with perforations at two opposite ends in the direction of the optical path, the heat conducting plate is provided in a chamber, the heat conducting plate is provided with a placement groove along the direction of the optical path, the chirped fiber grating is arranged along the direction of the optical path and is arranged in the placement groove, and the chirped fiber grating passes through the perforations; the number of temperature control components is an odd number, the temperature control components are connected to the heat conducting plate and are evenly distributed along the heat conducting plate; the temperature control component comprises a temperature sensor and a semiconductor cooling plate, the heat conducting plate has a bottom surface on the back side relative to the placement groove, the semiconductor cooling plate is adjacent to the bottom surface, the temperature sensor is close to the semiconductor cooling plate and adjacent to the heat conducting plate; the temperature sensor and the semiconductor cooling plate are connected to the main control circuit board. The temperature of different positions of the fiber grating is managed to achieve more accurate temperature control, so as to obtain more accurate dispersion tuning.

Description

Technical Field

[0001] The invention relates to the field of optical equipment, and in particular to a tuning device for a fiber grating. Background Art

[0002] Dispersion is a core parameter in fiber Bragg gratings, which characterizes the relationship between wavelength and propagation speed. In fiber-optic communication systems, dispersion needs to be reduced to ensure that optical signals do not experience bit errors and distortion during transmission.

[0003] In fiber chirped pulse amplification (FCPA) technology, only by achieving reasonable compensation for dispersion can ultrashort pulses close to the Fourier transform limit be obtained. General fiber laser transmission systems only need to solve the matching problem of second-order dispersion, while in ultra-high-speed fiber-optic communications and laser amplification systems with pulse widths of less than 100 femtoseconds, it is also necessary to consider the influence of higher-order, especially third-order dispersion. By changing the dispersion amount of the fiber Bragg grating, compensating for the dispersion introduced by other devices and fiber materials in the system, and achieving overall dispersion compensation, the system can achieve optimal working performance.

[0004] For dispersion tuning, once the fiber Bragg grating device is manufactured, the intrinsic dispersion is determined immediately, but the dispersion parameters of the grating can be changed by changing the external environment. Common methods include tension tuning, pressure tuning, and temperature tuning. The response speed is fast when adjusting the grating by tension and pressure, but it is easy to damage the optical fiber, thus affecting the long-term stability of the device. Temperature tuning can slowly change the refractive index of the fiber Bragg grating without introducing additional losses, which is a more suitable control solution. Summary of the invention

[0005] The object of the present invention is to provide a tuning device for a fiber Bragg grating which can realize accurate tuning of the third-order dispersion of the fiber Bragg grating.

[0006] In order to achieve the purpose of the present invention, the present invention provides a tuning device for a fiber grating, comprising a shell, a chirped fiber grating and a heat conducting plate, wherein the shell forms a relatively closed chamber, the shell is provided with through holes at two opposite ends in the direction of the optical path, the heat conducting plate is arranged in the chamber, the heat conducting plate is provided with a placement groove along the direction of the optical path, the chirped fiber grating is arranged along the direction of the optical path and is arranged in the placement groove, and the chirped fiber grating passes through the through hole; the tuning device also comprises at least five temperature control components and a main control circuit board arranged in the chamber, the number of the temperature control components is an odd number, the temperature control components are connected to the heat conducting plate and are evenly distributed along the heat conducting plate; the temperature control component comprises a temperature sensor and a semiconductor cooling plate, the heat conducting plate has a bottom surface on the back side relative to the placement groove, the semiconductor cooling plate is adjacent to the bottom surface, the temperature sensor is close to the semiconductor cooling plate and adjacent to the heat conducting plate; the temperature sensor and the semiconductor cooling plate are connected to the main control circuit board.

[0007] A further solution is that the heat conducting plate is provided with a temperature detection groove near each semiconductor refrigeration plate, the temperature detection groove is close to the placement groove, and the temperature sensor is arranged in the temperature detection groove.

[0008] A further solution is that the pins of the temperature sensor and the pins of the semiconductor cooling sheet are located on the same side, the main control circuit board is located on the side of the heat conduction plate, and the pins of the temperature sensor and the pins of the semiconductor cooling sheet are connected to the main control circuit board.

[0009] A further solution is that a connection window is provided on the outer wall of the shell, and a communication interface is provided on the main control circuit board, and the communication interface is located at the connection window.

[0010] A further solution is that the shell is provided with a limit groove in the chamber, and the main control circuit board is installed in the limit groove.

[0011] A further solution is that the number of temperature control components is seven.

[0012] A further solution is that the shell is provided with at least five mounting grooves in the chamber, the mounting grooves are arranged along the light path direction, and the semiconductor cooling plate is located in the mounting groove and adjacent to the mounting groove.

[0013] A further solution is that a mounting platform is provided on the bottom wall of the shell in the chamber, and the mounting grooves are all located on the top surface of the mounting platform.

[0014] A further solution is that the shell includes a base and a cover, and the cover covers the base to enclose a chamber.

[0015] A further solution is that a first half hole is provided on the side wall of the base in the direction of the light path, and a second half hole is provided on the side wall of the cover in the direction of the light path, and the first half hole and the second half hole constitute a through hole.

[0016] The beneficial effect of the present invention is that a chirped fiber Bragg grating, a heat conducting plate, a temperature control component and a main control circuit board are arranged in a relatively closed chamber, so that temperature control can be performed in a relatively stable environment, and an odd number of temperature control components are evenly distributed to manage the temperature of different positions of the fiber Bragg grating, so that the required dispersion parameter curve can be obtained, thereby realizing the third-order dispersion tuning of the fiber Bragg grating, and the temperature control of the semiconductor refrigeration plate located in the middle can realize the control of the middle peak or trough of the temperature curve, thereby realizing more precise temperature control, so as to obtain more accurate dispersion tuning.

[0017] In addition, by arranging the main control circuit board in the cavity and connecting it with multiple temperature sensors and semiconductor cooling sheets, the system integration of the tuning device is improved, and the assembly is convenient and reliable. In addition, through the combination of a relatively closed base and a cover body, the device has a strong ability to resist environmental interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural diagram of an embodiment of a fiber Bragg grating tuning device of the present invention.

[0019] Figure 2 It is an exploded view of an embodiment of a fiber Bragg grating tuning device of the present invention.

[0020] Figure 3 It is a structural diagram of the base in the embodiment of the fiber Bragg grating tuning device of the present invention.

[0021] Figure 4 It is a schematic diagram of the coordination of the temperature control component in the embodiment of the fiber Bragg grating tuning device of the present invention.

[0022] Figure 5 It is a cross-sectional view perpendicular to the optical path direction in an embodiment of the fiber Bragg grating tuning device of the present invention.

[0023] Figure 6 It is a cross-sectional view along the optical path direction of an embodiment of the fiber Bragg grating tuning device of the present invention.

[0024] Figure 7 It is a schematic diagram of third-order dispersion measurement under different temperature distributions in an embodiment of the fiber Bragg grating tuning device of the present invention.

[0025] The present invention is further described below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0026] Reference Figures 1 to 6 The tuning device of the fiber Bragg grating in this case includes a shell 1, a chirped fiber Bragg grating 10, a heat conducting plate 21, seven temperature control components and a main control circuit board 22. The shell 1 includes a base 12 and a cover 11. The cover 11 covers the base 12 and forms a relatively closed chamber 14. The shell 1 is penetrated with a through hole 13 at two opposite ends in the optical path direction. Specifically, the base 12 is provided with a first half hole on the side wall in the optical path direction, and the cover 11 is provided with a second half hole on the side wall in the optical path direction. The first half hole and the second half hole constitute the through hole 13, and a sealing rubber member can be provided at the through hole 13.

[0027] The seven temperature control components, the main control circuit board 22 and the heat conducting plate 21 are all arranged in the chamber 14. The shell 1 is provided with a mounting platform 122 on the bottom wall in the chamber 14. Seven mounting grooves 123 are arranged on the top surface of the mounting platform 122. The multiple mounting grooves 123 are arranged along the optical path direction. The temperature control component includes a temperature sensor 24 and a semiconductor cooling plate 23. The semiconductor cooling plate 23 is located in the mounting groove 123 and is adjacent to the mounting groove 123.

[0028] The heat conducting plate 21 is located above the semiconductor cooling sheet 23. The heat conducting plate 21 is provided with a placement groove 211 along the optical path direction. The heat conducting plate 21 has a bottom surface on the back side relative to the placement groove 211. The semiconductor cooling sheet 23 is adjacent to the bottom surface. The heat conducting plate 21 is provided with a temperature detection groove at a position close to each semiconductor cooling sheet 23. The temperature detection groove is close to the placement groove 211. The temperature sensor 24 is arranged in the temperature detection groove. The pins of the temperature sensor 24 and the pins of the semiconductor cooling sheet 23 are located on the same side. In the thickness direction, the temperature sensor 24 is located between the semiconductor cooling sheet 23 and the placement groove 211. Then, the multiple temperature sensors 24 arranged along the optical path direction can detect the temperature distribution of the heat conducting plate 21 along the optical path direction.

[0029] The main control circuit board 22 is located on the side of the heat conducting plate 21, the pins of the temperature sensor 24 and the pins of the semiconductor refrigeration plate 23 are connected to the main control circuit board 22, the shell 1 is provided with a limiting groove 124 in the chamber 14, the main control circuit board 22 is installed in the limiting groove 124, the outer wall of the shell 1 is provided with a connecting window 121, and the main control circuit board 22 is provided with a communication interface 221, and the communication interface 221 is located at the connecting window 121.

[0030] The chirped fiber grating 10 is arranged along the optical path and disposed in the placement groove 211 , and two ends of the chirped fiber grating 10 pass through the through holes 13 at the two ends respectively, and the chirped fiber grating 10 passes through the sealing rubber member located at the through hole 13 .

[0031] Based on the temperature characteristics of fiber Bragg gratings, changes in ambient temperature will cause changes in the effective refractive index of the fiber and the grating period, which will in turn cause changes in the reflection wavelength of the grating. The Bragg wavelength of the fiber Bragg grating is given by the formula λ B =2n eff ·Λ represents, where Λ is the grating period, n eff is the effective refractive index of the core in the grating region. Both are related to temperature. The dispersion parameter of the fiber grating is given by the following formula:

[0032]

[0033] It is represented by, where L is the grating length and τ(λ) is the time delay function related to the wavelength.

[0034] When the temperature rises, the delay curve of the fiber Bragg grating drifts toward the long-wave direction, and the dispersion parameter D increases. When the temperature decreases, the delay curve of the fiber Bragg grating drifts toward the short-wave direction, and the dispersion parameter D decreases. Therefore, when the Bragg wavelength at different positions of the fiber Bragg grating changes, the reflection spectrum of the grating and the distribution of the dispersion parameter D will change in the wavelength direction. According to the following formula

[0035]

[0036] It can be seen that the third-order dispersion β of the fiber Bragg grating is 3 By obtaining the detected temperature of the temperature sensor and controlling multiple semiconductor refrigeration pieces, and then managing the temperature of different positions of the fiber grating, the required dispersion parameter curve can be obtained, such as Figure 7 As shown, the dotted line in the figure is the room temperature distribution, and the solid line is the Gaussian temperature distribution, thereby realizing the third-order dispersion tuning of the fiber Bragg grating.

[0037] The above scheme is only a preferred embodiment of this case. In practical applications, there are more variations. For example, by setting the temperature control component to an odd number such as 5, 7, 9, etc., the temperature at different positions of the fiber Bragg grating can be managed, thereby realizing the third-order dispersion tuning of the fiber Bragg grating. In addition to directly connecting the pins to the main control circuit board, wires can be used for connection, which can also realize temperature control and detection.

[0038] As can be seen from the above, a chirped fiber Bragg grating, a heat conduction plate, a temperature control component and a main control circuit board are arranged in a relatively closed chamber, and then the temperature can be controlled in a relatively stable environment to achieve the third-order dispersion tuning of the fiber Bragg grating. By utilizing the temperature control of the semiconductor refrigeration plate located in the middle, the middle peak or trough of the temperature curve can be controlled, and then more precise temperature control can be achieved to obtain more accurate dispersion tuning.

Claims

1. A tuning device for a fiber Bragg grating, comprising a housing, a chirped fiber Bragg grating and a heat conducting plate, wherein the housing encloses a relatively closed chamber, the housing is provided with through holes at two opposite ends in the direction of an optical path, the heat conducting plate is arranged in the chamber, the heat conducting plate is provided with a placement groove along the direction of the optical path, the chirped fiber Bragg grating is arranged along the direction of the optical path and is arranged in the placement groove, and the chirped fiber Bragg grating passes through the through holes; Features: The tuning device further comprises at least five temperature control components and a main control circuit board arranged in the chamber, the number of the temperature control components is an odd number, and the temperature control components are connected to the heat conducting plate and are evenly distributed along the heat conducting plate; The temperature control assembly includes a temperature sensor and a semiconductor cooling sheet, the heat conducting plate has a bottom surface on the back side relative to the placement groove, the semiconductor cooling sheet is adjacent to the bottom surface, and the temperature sensor is close to the semiconductor cooling sheet and adjacent to the heat conducting plate; The temperature sensor and the semiconductor refrigeration chip are connected to the main control circuit board; The heat conducting plate is provided with a temperature detection groove at a position close to each of the semiconductor refrigeration sheets, the temperature detection groove is close to the placement groove, and the temperature sensor is arranged in the temperature detection groove; The pins of the temperature sensor and the pins of the semiconductor refrigeration sheet are located on the same side, the main control circuit board is located on the side of the heat conducting plate, and the pins of the temperature sensor and the pins of the semiconductor refrigeration sheet are connected to the main control circuit board; The outer wall of the shell is provided with a connection window, and the main control circuit board is provided with a communication interface, and the communication interface is located at the connection window.

2. The tuning device according to claim 1, characterized in that: The shell is provided with a limiting groove in the chamber, and the main control circuit board is installed in the limiting groove.

3. The tuning device according to claim 1, characterized in that: The number of the temperature control components is seven.

4. The tuning device according to any one of claims 1 to 3, characterized in that: The shell is provided with at least five mounting grooves in the chamber, the mounting grooves are arranged along the direction of the light path, and the semiconductor cooling plate is located in the mounting grooves and is adjacent to the mounting grooves.

5. The tuning device according to claim 4, characterized in that: The bottom wall of the shell in the chamber is provided with a mounting platform, and the mounting grooves are all located on the top surface of the mounting platform.

6. The tuning device according to any one of claims 1 to 3, characterized in that: The shell comprises a base and a cover, wherein the cover covers the base and encloses the chamber.

7. The tuning device according to claim 6, characterized in that: The base is provided with a first half hole on the side wall in the direction of the light path, and the cover is provided with a second half hole on the side wall in the direction of the light path. The first half hole and the second half hole constitute the through hole.

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