Temperature self-sensing photon chip, temperature sensing device thereof and signal demodulation method

Abstract

The invention discloses an optical fiber temperature sensing device and a signal demodulation method, and the method comprises the steps: carrying out the first-stage light splitting of incident light through an array waveguide grating, enabling the light of a plurality of wavebands to enter a plurality of sensing optical fibers, carrying out the second-stage light splitting of the incident light of a single waveband through a plurality of temperature sensing structures which are sequentially arranged, and enabling the light of a plurality of sub-wavebands to be divided into light of a plurality of sub-wavebands; and obtaining temperature sensing signals which respectively correspond to the arrays formed by the temperature sensing structures on the plurality of optical fibers, thereby realizing temperature distribution sensing among micro-intervals. The invention further discloses a temperature self-sensing photon chip, the optical fiber temperature sensing device is arranged on the chip body, and the temperature self-sensing photon chip is compact in structure, small in size and low in power consumption. Meanwhile, the temperature of the chip is monitored and calibrated in real time through the optical fiber temperature sensing device, and the influence on the temperature of the integrated photon chip is conveniently corrected.

Description

Technical Field

[0001] The present invention relates to the technical field of photon chips, and in particular to a temperature self-sensing photon chip, an optical fiber temperature sensing device thereof, and a signal demodulation method. Background Art

[0002] The typical size of the silicon-based silica material system, which is currently the most widely used, is on the order of 10cm2, so complex devices integrated with other devices often cannot be made on a single chip. With the development of large-scale integrated devices, the miniaturization of devices is an inevitable trend. Increasing the refractive index difference between the waveguide core and the cladding can confine the light to a smaller waveguide, reduce the bending radius of the waveguide at the same bending loss, and reduce the spacing of the array waveguide at the same crosstalk, thereby reducing the size of the device.

[0003] The material refractive index and length of the traditional silicon-based silica optical waveguide structure change with temperature, causing the central wavelength to drift with temperature, affecting the performance of the integrated photonic chip, thus limiting its application in practical systems. Conventional temperature sensors are large in size, high in power consumption, and complex in structure, and the chip itself requires cumbersome process modifications. In addition, it is difficult to correct the photonic chip signal based on the sensing signal of the temperature sensor, which also increases the difficulty of signal processing in the chip. Summary of the invention

[0004] In order to solve the technical problems existing in the background technology, the present invention proposes a temperature self-sensing photonic chip, an optical fiber temperature sensing device and a signal demodulation method thereof.

[0005] The present invention provides an optical fiber temperature sensing device, comprising: an arrayed waveguide grating, a plurality of sensing optical fibers and a plurality of circulators;

[0006] The arrayed waveguide grating is provided with a first input end and a plurality of first output ends, each circulator is provided with a second input end, an optical fiber connection end and a second output end, and each of the first output ends is signal-connected to the second input end of a circulator;

[0007] One end of each sensing optical fiber is connected to the optical fiber connecting end of the circulator, and each sensing optical fiber is provided with a plurality of temperature sensing structures, which are sequentially spaced along the length direction of the sensing optical fiber.

[0008] Preferably, a plurality of sensing optical fibers are arranged in parallel and spaced apart in sequence, so that a plurality of temperature sensing structure arrays are distributed to form a sensing array.

[0009] Preferably, the temperature sensing structures on two adjacent sensing optical fibers are arranged in a one-to-one correspondence.

[0010] Preferably, two adjacent temperature sensing structures on two adjacent sensing optical fibers are arranged at equal intervals.

[0011] In the present invention, in the proposed optical fiber temperature sensing device, each first output end of the arrayed waveguide grating is signal-connected to the second input end of a circulator; multiple sensing optical fibers are arranged side by side, one end of the sensing optical fiber is connected to the optical fiber connection end of the circulator, and multiple temperature sensing structures are provided on each sensing optical fiber, and the multiple temperature sensing structures are sequentially arranged and spaced along the length direction of the sensing optical fiber. Through the above-mentioned optimized optical fiber temperature sensing device, the incident light is subjected to primary spectral splitting by the arrayed waveguide grating, and the light divided into multiple bands is respectively incident on multiple sensing optical fibers, and the incident light of a single band is subjected to secondary spectral splitting by multiple temperature sensing structures arranged in sequence, and is divided into multiple sub-bands of light, and a temperature sensing signal containing an array formed by temperature sensing structures corresponding to multiple optical fibers is obtained, which is convenient for signal processing, thereby realizing temperature distribution sensing in a small interval.

[0012] The present invention also provides a temperature sensing signal demodulation method for the above optical fiber temperature sensing device, which calculates the temperature change based on the output spectrum signal of the second output end of the circulator and the input spectrum signal of the first input end of the arrayed waveguide grating.

[0013] Preferably, the temperature change is calculated by the following equation:

[0014]

[0015]

[0016] Where ΔT is the temperature change function, R FBG(λ) is the FBG reflection spectrum function at the second output end of the circulator, R0 is the normalization factor of the FBG reflection spectrum at the second output end of the circulator, λ and λ n are the incident light wavelength and the center wavelength of the nth AWG channel, λ FBG is the central wavelength of FBG, Δλ n is the half-peak bandwidth of the nth AWG channel, Δλ FBG is the half-peak bandwidth of FBG, P n is the output optical power of the nth channel.

[0017] In the present invention, the proposed optical fiber temperature signal demodulation method calculates the temperature change based on the output spectrum signal of the second output end of the circulator and the input spectrum signal of the first input end of the array waveguide grating. By reasonably controlling the calculation algorithm, it is possible to realize the processing of the optical signal while realizing real-time monitoring and calibration of the temperature of the corresponding area of ​​the array.

[0018] The present invention also proposes a temperature self-sensing photonic chip, comprising a chip body and the above-mentioned optical fiber temperature sensing device; the multiple sensing optical fibers are arranged along the chip body.

[0019] Preferably, the sensing optical fiber is located below the chip body, and the arrayed waveguide grating is located above the chip body.

[0020] Preferably, the first input terminal and the second output terminal are respectively located on two sides of the chip body.

[0021] In the present invention, the proposed temperature self-sensing photonic chip is provided with an optical fiber temperature sensing device on the chip body, which has a compact structure, a simple combination method, a small size, low power consumption, and an external sensing structure without the need to modify the chip itself, which greatly reduces the equipment cost. In addition, the temperature distribution of the chip can be sensed by the optical fiber temperature sensing device, and the real-time monitoring and calibration of the chip temperature can be achieved, which facilitates the correction of the influence on the temperature of the integrated photonic chip and improves the reliability of the integrated photonic chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic structural diagram of an implementation of a temperature self-sensing photonic chip proposed by the present invention.

[0023] Figure 2 This is a schematic diagram of the distribution of the temperature sensing structure in one embodiment of a temperature self-sensing photonic chip proposed by the present invention.

[0024] Figure 3 A diagram of wavelength and output optical power in an implementation of a temperature self-sensing photonic chip proposed by the present invention. DETAILED DESCRIPTION

[0025] like Figures 1 to 3 As shown, Figure 1 This is a schematic diagram of the structure of an embodiment of a temperature self-sensing photonic chip proposed by the present invention. Figure 2 This is a schematic diagram of the distribution of the temperature sensing structure in one embodiment of a temperature self-sensing photonic chip proposed by the present invention. Figure 3 A diagram of wavelength and output optical power in an implementation of a temperature self-sensing photonic chip proposed by the present invention.

[0026] Reference Figure 1 and 2 , an optical fiber temperature sensing device proposed by the present invention comprises: an arrayed waveguide grating 2, a plurality of sensing optical fibers 3 and a plurality of circulators 5;

[0027] The arrayed waveguide grating 2 is provided with a first input end 1 and a plurality of first output ends, each circulator 5 is provided with a second input end, an optical fiber connection end and a second output end 6, and each of the first output ends is signal-connected to the second input end of a circulator 5;

[0028] One end of each sensing optical fiber 3 is connected to the optical fiber connection end of the circulator 5 , and a plurality of temperature sensing structures 4 are provided on each sensing optical fiber 3 . The plurality of temperature sensing structures 4 are sequentially spaced apart along the length direction of the sensing optical fiber 3 .

[0029] In order to explain in detail the specific working mode of the optical fiber temperature sensing device of this embodiment, this embodiment also proposes a temperature self-sensing photonic chip, including a chip body 10 and the above-mentioned optical fiber temperature sensing device; the multiple sensing optical fibers 3 are arranged along the chip body 10, so that the temperature sensing structure is distributed in an array on the surface of the chip body 10.

[0030] During the optical signal transmission process, the optical signal first enters the arrayed waveguide grating 2 through the first input end 1, and enters the temperature sensing structure 4 in the sensing optical fiber 3 through the circulator 5 via the first output end and the second input end. The optical signal is reflected by the temperature sensing structure 4 of the sensing optical fiber and then emitted through the second output end 6. In this process, the incident optical signal is subjected to primary light splitting by the arrayed waveguide grating, and the light divided into multiple bands is respectively incident on multiple sensing optical fibers. The incident light of a single band is subjected to secondary light splitting again by multiple temperature sensing structures arranged in sequence, and is divided into multiple sub-bands of light, and a temperature sensing signal containing an array formed by the temperature sensing structures corresponding to the multiple optical fibers is obtained, thereby realizing the temperature distribution sensing between the micro-intervals of the chip body.

[0031] During signal processing, the temperature change is calculated based on the output spectrum signal of the second output terminal 6 of the circulator 5 and the input spectrum signal of the first input terminal 1 of the arrayed waveguide grating 2, so as to realize real-time monitoring of the temperature distribution on the chip body.

[0032] In the specific signal processing process, the temperature change is calculated by the following equation:

[0033]

[0034] Where ΔT is the temperature change function, R FBG(λ) is the FBG reflection spectrum function of the second output end 6 of the circulator 5, R0 is the normalization factor of the FBG reflection spectrum of the second output end 6 of the circulator 5, λ and λ n are the incident light wavelength and the center wavelength of the nth AWG channel, λ FBG is the central wavelength of FBG, Δλ n is the half-peak bandwidth of the nth AWG channel, Δλ FBG is the half-peak bandwidth of FBG, P n is the output optical power of the nth channel.

[0035] By combining the above four equations, we can get the temperature change function ΔT.

[0036] In this embodiment, the proposed temperature self-sensing photonic chip is composed of an optical waveguide structure, a chip body and an optical fiber sensor array. The upper layer of the chip body is an optical waveguide structure, and the lower layer is an optical fiber sensor array. The optical waveguide structure is an array waveguide grating, which can not only perform spectroscopic processing on optical signals, but also process optical signals of the optical sensing structure to achieve temperature demodulation. By laying multiple optical fiber sensing structure arrays under the substrate, the additional structure can prevent the modification of the chip itself from causing cumbersome processes, and can monitor the integrated photonic chip in real time, timely correct the impact of temperature changes on the integrated photonic chip, and improve the reliability of the integrated photonic chip.

[0037] In the specific design of the optical fiber temperature sensing device, multiple sensing optical fibers 3 are arranged in parallel and at intervals in sequence, so that multiple temperature sensing structures 4 are distributed in an array to form a sensing array, which facilitates the array arrangement of the temperature sensing structures.

[0038] In a specific embodiment, the temperature sensing structures 4 on two adjacent sensing optical fibers 3 are arranged in a one-to-one correspondence, and the two adjacent temperature sensing structures 4 on two adjacent sensing optical fibers 3 are arranged at equal intervals. This makes the temperature sensing structures evenly distributed, and further makes the light entering the sensing optical fiber split into multiple evenly distributed sub-bands, which is convenient for subsequent optical signal processing.

[0039] In the specific design of the temperature self-sensing photonic chip, the sensing optical fiber 3 is located below the chip body, and the arrayed waveguide grating 2 is located above the chip body 10, which is convenient for external optical devices on the chip. Furthermore, in order to facilitate the connection of the signal input end and the output end, the first input end 1 and the second output end 6 can be located on both sides of the chip body 10 respectively.

[0040] The temperature self-sensing photonic chip of this embodiment is described in detail below through specific examples.

[0041] This embodiment proposes a temperature self-sensing photonic chip, including: an arrayed waveguide grating, a sensing optical fiber, a temperature sensing structure 4 and a circulator 5. It is composed of a sensing array consisting of an arrayed waveguide grating, a chip body and a temperature sensing structure. The upper layer of the chip body is an arrayed waveguide grating, and the lower layer is a sensing array. The arrayed waveguide grating can not only perform spectroscopic processing on the optical signal, but also process the optical signal of the optical sensing structure to realize temperature demodulation. First, light is coupled with the arrayed waveguide grating through the first input end 1, and the optical signal enters the arrayed waveguide grating 2, enters the temperature sensing structure 4 in the sensing optical fiber 3 through the optical fiber circulator 5, and the optical signal is reflected by the temperature sensing structure 4 and then emitted through the output end 6.

[0042] When processing optical signals, refer to Figure 3 , the edge filtering demodulation principle is shown in the figure. m-1 ,λ m ,λm+1 is the FBG center wavelength that drifts with the change of external physical quantities, P λm-1 ,P λm, P λm+1 It is the output optical power corresponding to the same output channel of the AWG. The solid line is the transmission spectrum of the AWG output channel, and the dotted line is the reflection spectrum of the FBG. The light reflected from the FBG has a wavelength corresponding to the passband edge of an AWG output channel. The change of the FBG center wavelength is converted into the change of the optical power transmitted by the AWG output channel. The relationship between the FBG wavelength and the edge optical power of the AWG output channel can be used to demodulate the FBG wavelength.

[0043] In the AWG wavelength demodulation system, the transmission spectrum function of AWG channel n and the reflection spectrum function of FBG are:

[0044]

[0045] Where T0 is the normalization factor of the AWG transmission spectrum, R0 is the normalization factor of the FBG reflection spectrum, λ and λ n is the incident light wavelength and the center wavelength of AWG channel n, λFBG is the center wavelength of FBG, Δλ n is the half-peak bandwidth of AWG channel n, λ FBG is the half-peak bandwidth of FBG.

[0046] From the above formula, the output optical power of channel n can be obtained as:

[0047]

[0048] Once the AWG and FBG are determined, the power P n With Δλ n and Δλ FBG related.

[0049] The relationship between the AWG center wavelength drift and temperature:

[0050]

[0051] The relationship between FBG center wavelength drift and temperature:

[0052]

[0053] By measuring a channel P n The temperature change can be solved by combining equations (2), (3), (4) and (5).

[0054] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A temperature sensing device, characterized in that: include: An arrayed waveguide grating (2), a plurality of sensing optical fibers (3) and a plurality of circulators (5); The arrayed waveguide grating (2) is provided with a first input end (1) and a plurality of first output ends, each circulator (5) is provided with a second input end, an optical fiber connection end and a second output end (6), and each of the first output ends is signal-connected to the second input end of a circulator (5); One end of each sensing optical fiber (3) is connected to the optical fiber connection end of the circulator (5), and each sensing optical fiber (3) is provided with a plurality of temperature sensing structures (4), which are arranged in sequence and at intervals along the length direction of the sensing optical fiber (3).

2. The optical fiber temperature sensing device according to claim 1, characterized in that: A plurality of sensing optical fibers (3) are arranged in parallel and at intervals in sequence, so that a plurality of temperature sensing structures (4) are distributed in an array to form a sensing array.

3. The optical fiber temperature sensing device according to claim 2, characterized in that: The temperature sensing structures (4) on two adjacent sensing optical fibers (3) are arranged in a one-to-one correspondence.

4. The optical fiber temperature sensing device according to claim 2, characterized in that: Two adjacent temperature sensing structures (4) on two adjacent sensing optical fibers (3) are arranged at equal intervals.

5. A method for demodulating a temperature sensing signal of an optical fiber temperature sensing device according to any one of claims 1 to 4, characterized in that: The temperature change is calculated based on the output spectrum signal of the second output end (6) of the circulator (5) and the input spectrum signal of the first input end (1) of the arrayed waveguide grating (2).

6. The temperature sensing signal demodulation method according to claim 5, characterized in that: The temperature change is calculated by the following equation: Where ΔT is the temperature change function, R FBG(λ) is the FBG reflection spectrum function of the second output end (6) of the circulator (5), R0 is the normalization factor of the FBG reflection spectrum of the second output end (6) of the circulator (5), λ and λ n are the incident light wavelength and the center wavelength of the nth AWG channel, λ FBG is the central wavelength of FBG, Δλ n is the half-peak bandwidth of the nth AWG channel, Δλ FBG is the half-peak bandwidth of FBG, P n is the output optical power of the nth channel.

7. A temperature self-sensing photonic chip, characterized in that: It comprises a chip body (10) and the optical fiber temperature sensing device according to any one of claims 1 to 4; the plurality of sensing optical fibers (3) are arranged along the chip body (10).

8. The temperature self-sensing photonic chip according to claim 7, characterized in that: The sensing optical fiber (3) is located below the chip body (10), and the arrayed waveguide grating (2) is located above the chip body (10).

9. The temperature self-sensing photonic chip according to claim 7, characterized in that: The first input end (1) and the second output end (6) are respectively located on two sides of the chip body (10).

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