CN107733524B - Detector with flexible film PIN photodiode array - Google Patents

Abstract

A detector with a flexible thin film PIN photodiode array, including a row selection logic unit, an analog signal processing unit array, an AD conversion unit array and a processing host connected in series through a data bus, and is also provided with a flexible PIN photodiode collection array , the input end of the flexible PIN photodiode collection array is connected to the output end of the selection logic unit through a data bus, and the output end of the flexible PIN photodiode collection array is connected to the input end of the analog signal processing unit array through a data bus , the control output terminal of the processing host is connected to the control input terminal of the row selection logic unit through a control bus. The invention can perform high-speed and high-precision optical fiber line light leakage fault detection, and can directly cover around the optical fiber to realize real-time fault detection of the entire optical fiber line or key optical fiber segments. It can greatly improve detection accuracy, response speed, and reduce the cost of optical fiber fault detectors.

Description

A detector with a flexible thin film PIN photodiode array

Technical field

The present invention relates to a photodetector. In particular, it relates to a detector with a flexible thin film PIN photodiode array for light leakage detection in optical communication systems.

Background technique

In optical fiber communication systems, light is the main medium for information transmission, and optical fiber is the main channel for optical transmission. Although under ideal circumstances, we believe that the light transmitted in the optical fiber is transmitted in a straight line, even if the optical path changes, it will be transmitted from the transmitting end to the receiving end without scattering leakage due to total reflection. However, the bending of the optical fiber caused by wiring or environmental changes will cause the angle of the light in the optical fiber to not meet the requirements of the critical angle of total reflection, causing scattering and leakage of the light in the optical fiber. Similarly, damage to the optical fiber or breakage caused by external force will also cause light leakage during transmission, which will affect the quality of optical communication and even directly cause communication interruption.

Therefore, we hope to detect the intensity and location of light leakage during optical fiber transmission as sensitively, quickly and accurately as possible, so as to quickly locate the fault and complete the emergency repair of the optical communication line. Existing optical fiber line fault detection devices mainly use the attenuation of power after optical fiber faults to detect optical fiber system faults. However, the detection response speed is slow, the equipment is bulky and complex, and this method only detects large-area light leakage caused by optical fiber breakage. Only then can we have good detection results.

Patent CN1376908 proposes a method for detecting optical fiber faults based on the ANS noise generated when the optical fiber is broken. This detection method can achieve a faster detection response speed than the traditional detection method, but the equipment is still expensive and complex, and it is only suitable for large-area light. Leakage has the disadvantage of good detection results, and it cannot fully meet the detection needs of large-area laying of optical fiber lines.

Contents of the invention

The technical problem to be solved by the present invention is to provide a detector with a flexible thin film PIN photodiode array that can perform high-speed and high-precision optical fiber line light leakage fault detection.

The technical solution adopted by the present invention is: a detector with a flexible thin film PIN photodiode array, including a row selection logic unit, an analog signal processing unit array, an AD conversion unit array and a processing host connected in series through a data bus. A flexible PIN photodiode collection array is also provided. The input end of the flexible PIN photodiode collection array is connected to the output end of the selection logic unit through a data bus. The output end of the flexible PIN photodiode collection array is connected to all the selection logic units through a data bus. The input end of the analog signal processing unit array, the control output end of the processing host is connected to the control input end of the row selection logic unit through a control bus.

When the processing host is a remote device, the processing host communicates with the AD conversion unit array and the row selection logic unit respectively through a relay device.

The flexible PIN photodiode collection array includes 5 to 15 flexible PIN photodiode collection units with the same structure arranged side by side, and the input ends of the 5 to 15 flexible PIN photodiode collection units arranged side by side are respectively connected to the Row selection logic unit, the analog signal processing unit array includes 5 to 15 analog signal processing units arranged side by side and connected in one-to-one correspondence with the output ends of the 5 to 15 flexible PIN photodiode acquisition units, and the AD The conversion unit array includes 5 to 15 AD conversion circuits arranged side by side and connected to the output terminals of the 5 to 15 analog signal processing units in one-to-one correspondence.

Each of the flexible PIN photodiode collection units includes a first flexible thin film photodiode, a second flexible thin film photodiode and a flexible thin film transistor. The anodes of the first flexible thin film photodiode and the second flexible thin film photodiode The negative electrode is connected to the ground, the drain electrode of the flexible thin film transistor is connected, the gate electrode of the flexible thin film transistor is connected to the row selection logic unit, and the source electrode is connected to the input end of the corresponding amplification circuit in the analog signal processing unit array.

The specific structure of each flexible PIN photodiode collection unit includes: a PET plastic substrate and an SU8 material layer provided on the upper end surface of the PET plastic substrate. Flexible thin film transistors are respectively provided on the SU8 material layer. The structure of the first flexible thin film photodiode and the second flexible thin film photodiode, the flexible thin film transistors are respectively connected to the first flexible thin film photodiode and the second flexible thin film photodiode through interconnect metal, and connected to the row selection logic unit and amplifier circuit.

The structure of the flexible thin film transistor includes an N-type doped region of the first monocrystalline silicon film, an undoped region of the first monocrystalline silicon film and a second monocrystalline silicon film arranged side by side on the upper end surface of the SU8 material layer. N-type doped region of the film, an active electrode is provided on the N-type doped region of the first single crystal silicon film, a gate electrode is provided on the undoped region of the first single crystal silicon film through a gate oxide layer, and A drain electrode is provided on the N-type doped region of the second single crystal silicon film, wherein the source electrode is connected to a signal output port through an interconnection metal, and the signal output port is connected to the input end of the corresponding amplification circuit in the analog signal processing unit array. , the gate electrode is connected to the switch control port, the switch control port is connected to the output end of the row selection logic unit, and the drain electrode is connected to the cathode of the first flexible film photodiode and the second flexible film photodiode through the interconnection metal.

The structure of the first flexible thin film photodiode and the second flexible thin film photodiode includes a third single crystal silicon thin film N-type doped region and a second single crystal silicon thin film arranged side by side on the upper end surface of the SU8 material layer. The undoped area, the P-type doped area of the single crystal silicon film, the undoped area of the third single crystal silicon film, and the N-type doped area of the fourth single crystal silicon film, and the third single crystal silicon film is N-type doped. A first N-region electrode is provided on the region, a P-region electrode is provided on the P-type doped region of the single-crystal silicon film, and a second N-region electrode is provided on the N-type doped region of the fourth single-crystal silicon film, The P-region electrode forms a positive electrode and is connected to the ground terminal through an interconnection metal. The first N-region electrode and the second N-region electrode form a negative electrode and is connected to the drain electrode of the flexible thin film transistor through the interconnection metal.

The detector with a flexible thin film PIN photodiode array of the present invention can perform high-speed and high-precision optical fiber line light leakage fault detection. The detector has good fit with the optical fiber and does not need to use more complex and expensive optical power detection equipment. It has low cost and can be used to detect light leakage faults in the entire optical fiber or key optical fiber segments, and is suitable for promotion. The photodiode part in the detector of the present invention adopts thin film flexible PIN photodiode, which has the characteristics of small area, simple structure and low price. More importantly, due to its good bendable mechanical properties, the detector of the present invention can be directly covered around the optical fiber to realize real-time fault detection of the entire optical fiber line or key optical fiber segments. Therefore, the detector with a flexible thin film PIN photodiode array of the present invention can greatly improve the detection accuracy and response speed, and reduce the cost of the optical fiber fault detector.

Description of the drawings

Figure 1 is a block diagram of a detector with a flexible thin film PIN photodiode array according to the first embodiment of the present invention;

Figure 2 is a block diagram of a detector with a flexible thin film PIN photodiode array according to the second embodiment of the present invention;

Figure 3 is a schematic structural diagram of the flexible PIN photodiode collection array in the present invention;

Figure 4 is a circuit schematic diagram of the flexible PIN photodiode collection unit in the flexible PIN photodiode collection array;

Figure 5 is a schematic structural diagram of the flexible PIN photodiode collection unit in the flexible PIN photodiode collection array;

Figure 6 is a side view of the flexible thin film transistor part in Figure 5;

FIG. 7 is a side view of the flexible photodiode portion of FIG. 5 .

In the picture

101: Row selection logic unit 102: Flexible PIN photodiode collection array

103: Analog signal processing unit array 104: AD conversion unit array

105: Processing host 106: Data bus

107: Control bus 108: Relay device

1021: Flexible PIN photodiode collection unit 1: Third single crystal silicon film N-type doped region

2: Undoped area of the second single crystal silicon film 3: P-type doped area of the single crystal silicon film

4: Undoped area of the third single crystal silicon film 5: N-type doped area of the fourth single crystal silicon film

6: Ground terminal 7: Signal output port

8: N-type doped area of the first single crystal silicon film 9: Undoped area of the first single crystal silicon film

10: Second monocrystalline silicon film N-type doped region 11: Switch control port

12: Interconnected metal 13: PET plastic substrate

14: SU8 material layer 15: First N-region electrode

16: P zone electrode 17: Second N zone electrode

18: Source electrode 19: Gate electrode

20: Gate oxide layer 21: Drain electrode

Detailed ways

A detector with a flexible thin film PIN photodiode array of the present invention will be described in detail below with reference to the embodiments and drawings.

As shown in Figure 1, a detector with a flexible thin film PIN photodiode array of the present invention includes a row selection logic unit 101, and an analog signal processing unit array 103 and an AD conversion unit array 104 connected in series through a data bus 106. And the processing host 105 is also provided with a flexible PIN photodiode collection array 102. The input end of the flexible PIN photodiode collection array 102 is connected to the output end of the selection logic unit 101 through the data bus 106. The flexible PIN photodiode collection array 102 The output end of the array 102 is connected to the input end of the analog signal processing unit array 103 through the data bus 106, and the control output end of the processing host 105 is connected to the control input end of the row selection logic unit 101 through the control bus 107.

As shown in Figure 2, when the processing host 105 is a remote device, the connection between the processing host 105 and the AD conversion unit array 104 and the row selection logic unit 101 is through a relay device 108. communication.

As shown in Figure 3, the flexible PIN photodiode collection array 102 includes 5 to 15 flexible PIN photodiode collection units 1021 with the same structure arranged side by side. The 5 to 15 flexible PIN photodiode collection units arranged side by side The input terminals of the unit 1021 are respectively connected to the row selection logic unit 101, and the analog signal processing unit array 103 includes one-to-one correspondence with the output terminals of the 5 to 15 flexible PIN photodiode acquisition units 1021 arranged side by side. There are 5 to 15 analog signal processing units. The AD conversion unit array 104 includes 5 to 15 AD conversion circuits arranged side by side and connected to the output terminals of the 5 to 15 analog signal processing units in one-to-one correspondence.

As shown in Figure 4, each of the flexible PIN photodiode collection units 1021 includes a first flexible thin film photodiode D1, a second flexible thin film photodiode D2 and a flexible thin film transistor T. The first flexible thin film photodiode The anode of the diode D1 and the second flexible thin film photodiode D2 is connected to the ground, the cathode is connected to the drain of the flexible thin film transistor T, the gate of the flexible thin film transistor T is connected to the row selection logic unit 101, and the source is connected to the analog signal processing unit array 103. The input terminal of the corresponding amplifier circuit.

Among them, the first flexible thin film photodiode D1 and the second flexible thin film photodiode D2 are used to detect the light leakage of the optical fiber, and the flexible thin film transistor T controls the opening and closing of the acquisition unit, and is used to control the opening and closing of a certain section of optical fiber. closure. And considering the overall coordination of the array, the flexible thin film transistor T, the first flexible thin film photodiode D1, and the second flexible thin film photodiode D2 all need to be connected to the main analysis circuit, and the analysis circuit coordinates the work and operation between each acquisition unit. Data is transferred back. The reverse current of the first flexible film photodiode D1 and the second flexible film photodiode D2 changes in proportion to the optical power and optical wavelength. Through experiments, a quantitative model of optical power, optical wavelength and photocurrent can be established, so the first flexible film photodiode can be The current signals generated by the flexible film photodiode D1 and the second flexible film photodiode D2 are transmitted back to obtain the power information of the optical fiber light leakage.

The photodiode part uses flexible PIN photodiodes, which have the characteristics of small area, simple structure and low price. More importantly, due to its good bendable mechanical properties, this detector can be directly covered around the optical fiber to achieve real-time fault detection of the entire optical fiber line or key optical fiber segments. Therefore, using this flexible PIN photodiode array detection method can greatly improve detection accuracy, response speed, and reduce the cost of fiber fault detectors.

As shown in Figures 5, 6, and 7, the specific structure of each flexible PIN photodiode collection unit 1021 includes: a PET plastic substrate 13 and an SU8 material disposed on the upper end surface of the PET plastic substrate 13 Layer 14, the SU8 material layer 14 is provided with the structure of the flexible thin film transistor T and the structure of the first flexible thin film photodiode D1 and the second flexible thin film photodiode D2 respectively. The flexible thin film transistor T is respectively arranged through the interconnection metal 12 The first flexible film photodiode D1 and the second flexible film photodiode D2 are connected, and the row selection logic unit 101 and the amplification circuit are connected.

As shown in Figures 5 and 6, the structure of the flexible thin film transistor T includes a first single crystal silicon film N-type doped region 8 arranged side by side on the upper end surface of the SU8 material layer 14, a first single crystal The undoped area 9 of the silicon film and the N-type doped area 10 of the second single-crystal silicon film. An active electrode 18 is provided on the N-type doped area 8 of the first single-crystal silicon film. The first single-crystal silicon film A gate electrode 19 is provided on the undoped region 9 through a gate oxide layer 20, and a drain electrode 21 is provided on the N-type doped region 10 of the second single crystal silicon film, wherein the source electrode 18 is connected through the interconnection metal 12 Signal output port 7. The signal output port 7 is connected to the input end of the corresponding amplification circuit in the analog signal processing unit array 103. The gate electrode 19 is connected to the switch control port 11. The switch control port 11 is connected to the row selection logic unit 101. At the output end, the drain electrode 21 is connected to the negative electrodes of the first flexible film photodiode D1 and the second flexible film photodiode D2 through the interconnection metal 12 .

As shown in Figures 5 and 7, the structures of the first flexible film photodiode D1 and the second flexible film photodiode D2 include a third single crystal silicon film arranged side by side on the upper end surface of the SU8 material layer 14 N-type doped region 1, second single-crystal silicon film undoped region 2, single-crystal silicon film P-type doped region 3, third single-crystal silicon film undoped region 4 and fourth single-crystal silicon film N-type Doped region 5, the first N-region electrode 15 is provided on the N-type doped region 1 of the third single-crystal silicon film, and the P-region electrode 16 is provided on the P-type doped region 3 of the single-crystal silicon film, so A second N-region electrode 17 is provided on the N-type doped region 5 of the fourth monocrystalline silicon film. The P-region electrode 16 forms a positive electrode and is grounded through the interconnection metal 12 and the ground terminal 6. The first N-region electrode 15 and The second N-region electrode 17 forms a negative electrode and is connected to the drain electrode 21 of the flexible thin film transistor T1 through the interconnection metal 12 .

The present invention is a detector with a flexible thin film PIN photodiode array. During detection, the flexible PIN photodiode collection array is closely attached to the surface of the optical fiber to be tested, and the row selection logic unit selects the flexible PIN of the corresponding detection section as needed. Photodiode collection unit. When the optical fiber leaks light due to bending, leakage or breakage, the reverse photocurrent generated by light excitation will cause corresponding changes in the DC characteristics of the first flexible film photodiode D1 and the second flexible film photodiode D2. This change will be sent to the comparator in the corresponding analog signal processing unit for comparison with the detection threshold current. If the result is greater than the detection threshold, the corresponding current signal will be transmitted to the corresponding AD conversion unit, converted into a digital signal and sent back to the processing host, and then the processing host will output the corresponding detection results, such as: light leakage position, light leakage power, etc., and Carry out next step of early warning control. The main function of the analog signal processing unit is to amplify and compare signals and improve the signal-to-noise ratio. At the same time, in order to make the detection results more accurate, the detector needs to add other control signals and noise processing mechanisms.

The present invention has been explained above by taking an optical fiber light leakage fault detector as an example. However, the present invention is not limited to this. The invention can also be applied in biomedical, military and other fields that require light detection, especially real-time light detection of curved objects.

At the same time, the present invention takes silicon film and PET flexible substrate as an example. Under other needs, the film material in this example can be replaced with other semiconductor materials such as germanium, and the substrate material can be replaced with other flexible materials such as fiber, degradable resin, etc. . In the present invention, two flexible PIN photodiodes are connected in parallel as an example. However, in order to improve detection accuracy and sensitivity in actual use, the number of parallel flexible PIN photodiodes can also be increased accordingly.

Claims (5)

1. A detector with a flexible thin film PIN photodiode array, including a row selection logic unit (101), and an analog signal processing unit array (103) and an AD conversion unit array (104) connected in series through a data bus (106) ) and a processing host (105), characterized in that a flexible PIN photodiode collection array (102) is also provided, and the input end of the flexible PIN photodiode collection array (102) is connected to the selection logic through a data bus (106) The output end of the unit (101) and the output end of the flexible PIN photodiode acquisition array (102) are connected to the input end of the analog signal processing unit array (103) through the data bus (106), and the processing host (105) The control output terminal is connected to the control input terminal of the row selection logic unit (101) through the control bus (107); The flexible PIN photodiode collection array (102) includes 5 to 15 flexible PIN photodiode collection units (1021) with the same structure arranged side by side. The 5 to 15 flexible PIN photodiode collection units (1021) arranged side by side. The input terminals of 1021) are respectively connected to the row selection logic unit (101), and the analog signal processing unit array (103) includes the outputs of the 5 to 15 flexible PIN photodiode acquisition units (1021) arranged side by side. The AD conversion unit array (104) includes 5 to 15 analog signal processing units connected to the output terminals of the 5 to 15 analog signal processing units in a one-to-one correspondence. 15 AD conversion circuits; Each of the flexible PIN photodiode collection units (1021) includes a first flexible thin film photodiode (D1), a second flexible thin film photodiode (D2) and a flexible thin film transistor (T). The anodes of the thin film photodiode (D1) and the second flexible thin film photodiode (D2) are connected to ground, the cathode is connected to the drain of the flexible thin film transistor (T), and the gate of the flexible thin film transistor (T) is connected to the row selection logic unit (101 ), the source is connected to the input end of the corresponding amplification circuit in the analog signal processing unit array (103); Among them, the first flexible thin film photodiode (D1) and the second flexible thin film photodiode (D2) are used to detect the light leakage of the optical fiber, while the flexible thin film transistor (T) controls the opening and closing of the acquisition unit, and is used to control a certain The opening and closing of a section of optical fiber detection; and taking into account the overall coordination of the array, the flexible thin film transistor (T), the first flexible thin film photodiode (D1), and the second flexible thin film photodiode (D2) are all connected to the main analysis circuit, The main analysis circuit coordinates the work and data transmission between each acquisition unit; the reverse current of the first flexible thin film photodiode (D1) and the second flexible thin film photodiode (D2) changes in proportion to the optical power and optical wavelength. , establish a quantitative model of optical power, optical wavelength and photocurrent through experiments, so the current signals generated by the first flexible thin film photodiode (D1) and the second flexible thin film photodiode (D2) are transmitted back to obtain the power of optical fiber light leakage information; During detection, the flexible PIN photodiode collection array is closely attached to the surface of the optical fiber to be tested, and the row selection logic unit selects the flexible PIN photodiode collection unit of the corresponding detection section as needed. When the optical fiber leaks due to bending or breakage, light leakage occurs. , the reverse photocurrent generated by light excitation will cause corresponding changes in the DC characteristics of the first flexible thin film photodiode (D1) and the second flexible thin film photodiode (D2), and this change is sent to the corresponding analog signal The comparator in the processing unit compares the detection threshold current. If the result is greater than the detection threshold, the corresponding current signal is transmitted to the corresponding AD conversion unit, converted into a digital signal and sent back to the processing host, and then the processing host outputs the corresponding detection result. Including: light leakage location, light leakage power, etc., and carry out the next step of early warning control. 2. A detector with a flexible thin film PIN photodiode array according to claim 1, characterized in that when the processing host (105) is a remote device, the processing host (105) respectively Communication with the AD conversion unit array (104) and the row selection logic unit (101) is through a relay device (108). 3. A detector with a flexible thin film PIN photodiode array according to claim 1, characterized in that the specific structure of each flexible PIN photodiode collection unit (1021) includes: a PET plastic substrate ( 13) and the SU8 material layer (14) provided on the upper end surface of the PET plastic substrate (13). The SU8 material layer (14) is respectively provided with a structure of a flexible thin film transistor (T) and a first flexible Structure of a thin film photodiode (D1) and a second flexible thin film photodiode (D2), the flexible thin film transistor (T) is respectively connected to the first flexible thin film photodiode (D1) and the second flexible thin film photodiode through an interconnect metal (12) diode (D2), and connects the row selection logic unit (101) and the amplifier circuit. 4. A detector with a flexible thin film PIN photodiode array according to claim 3, characterized in that the structure of the flexible thin film transistor (T) includes the SU8 material layer (14) arranged side by side. The first single crystal silicon film N-type doped region (8), the first single crystal silicon film undoped region (9) and the second single crystal silicon film N-type doped region (10) on the upper end surface, as described An active electrode (18) is provided on the N-type doped region (8) of the first single crystal silicon film, and a gate electrode is provided on the undoped region (9) of the first single crystal silicon film through a gate oxide layer (20). (19), a drain electrode (21) is provided on the N-type doped region (10) of the second single crystal silicon film, wherein the source electrode (18) is connected to the signal output port (7) through the interconnection metal (12) ), the signal output port (7) is connected to the input end of the corresponding amplification circuit in the analog signal processing unit array (103), the gate electrode (19) is connected to the switch control port (11), and the switch control port (11 ) is connected to the output end of the row selection logic unit (101), and the drain electrode (21) is connected to the negative electrodes of the first flexible film photodiode (D1) and the second flexible film photodiode (D2) through the interconnection metal (12). 5. A detector with a flexible film PIN photodiode array according to claim 3, characterized in that the structures of the first flexible film photodiode (D1) and the second flexible film photodiode (D2) It includes an N-type doped region (1) of the third single crystal silicon film, an undoped region (2) of the second single crystal silicon film, and a single crystal silicon film arranged side by side on the upper end surface of the SU8 material layer (14). P-type doped region (3), third single-crystal silicon film undoped region (4) and fourth single-crystal silicon film N-type doped region (5), the third single-crystal silicon film is N-type doped A first N-region electrode (15) is provided on the region (1), a P-region electrode (16) is provided on the P-type doped region (3) of the single crystal silicon film, and the fourth single-crystal silicon film is N-type. A second N-region electrode (17) is provided on the doped region (5). The P-region electrode (16) forms a positive electrode and is grounded through the interconnecting metal (12) and the ground terminal (6). The first N-region electrode (17) 15) and the second N-region electrode (17) form the negative electrode and are connected to the drain electrode (21) of the flexible thin film transistor (T1) through the interconnection metal (12).