CN211425818U - Polarizer straight waveguide tail fiber polarization crosstalk test system - Google Patents
Polarizer straight waveguide tail fiber polarization crosstalk test system Download PDFInfo
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- CN211425818U CN211425818U CN201922408642.6U CN201922408642U CN211425818U CN 211425818 U CN211425818 U CN 211425818U CN 201922408642 U CN201922408642 U CN 201922408642U CN 211425818 U CN211425818 U CN 211425818U
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Abstract
The utility model discloses a polarizer straight waveguide tail optical fiber polarization crosstalk test system, include: light source, branching unit, polarizer and collection system, the light source passes through the polarization maintaining fiber and is connected with the input of branching unit, the branching unit is equipped with a monitor port, one or more test port, the monitor port passes through the polarization maintaining fiber and is connected with collection system's monitor input, every the test port passes through the polarization maintaining fiber and is connected with a light path input of polarizer, each light path output of polarizer passes through the polarization maintaining fiber and is connected with the input of a device under test, each the output of device under test respectively with collection system's test input is connected. The utility model discloses a lithium niobate array straight waveguide of single polarization work has broken through the problem that the measuring accuracy is low, inefficiency and with high costs as the polarizer, adopts the multichannel collection appearance in addition, can realize the requirement that multichannel tail optical fiber polarization crosstalk and insertion loss gathered simultaneously.
Description
Technical Field
The utility model relates to an optical fiber correlation technique field, especially a polarizer straight waveguide tail optical fiber polarization crosstalk test system.
Background
In the optical fiber current transformer, the photoelectric performance of a lithium niobate straight waveguide phase modulator which is a key device has great influence on the performance of the whole sensor. The titanium-diffused lithium niobate straight waveguide phase modulator has a dual-polarization characteristic, can simultaneously transmit Transverse Electric (TE) and Transverse Magnetic (TM) modes, and can simultaneously modulate the phases of the two modes, which makes the titanium-diffused lithium niobate straight waveguide phase modulator popular in the field of optical fiber sensing, particularly in the development of optical fiber current sensors. As shown in fig. 1, a Super-luminescent Diode (SLD) light source 1 ', a light receiving component 2', a preamplifier 3 ', an a/D converter 4', a signal processor 5 ', a D/a converter 6', a circulator 7 ', a polarizer 8', a straight waveguide phase modulator 9 ', a polarization maintaining fiber delay 10', a λ/4 wave plate 11 ', a fiber ring 12', a reflector 13 ', and an intercepting conductor 14' form a fiber current transformer system. In the system, the optical fiber current sensor optical path formed by the straight waveguide phase modulator 8' has smaller temperature error and vibration error and better time reciprocity.
With the application of the current transformer, the temperature drift of the measurement accuracy is still a technical bottleneck restricting the high-performance current transformer, and the ti-diffused lithium niobate straight waveguide is one of the key components of the system, as shown in fig. 2, which is a schematic diagram of a straight waveguide structure, and includes a ti-diffused lithium niobate substrate 21 ', a waveguide 22 ', and an electrode 23 '. Research finds that under the full-temperature condition, the change of the polarization crosstalk of the tail fiber is the main cause of system polarization errors, and the low-temperature tail fiber polarization crosstalk degradation of the straight waveguide directly causes the low-temperature variation of the specific difference. In addition, system temperature noise is also an important factor influencing the high performance of the current transformer, and researches find that the insertion loss change of the straight waveguide has a direct relation with noise fluctuation, so that the polarization crosstalk and the insertion loss change of the all-temperature pigtail are two very critical indexes for evaluating the polarization error and the temperature noise of the system.
The existing testing method has the following defects:
because the titanium diffusion straight waveguide is in a dual-polarization working mode, the light input into the waveguide can be respectively tested after polarization, the polarization crosstalk of the tail fiber of the TE/TM can be respectively tested only by adopting an optical fiber type polarizer at the polarization part at present, the polarization crosstalk is about-20 dB, the polarization crosstalk of the tail fiber of the straight waveguide is better than-27 dB and is high even up to-34 dB, obviously, the optical fiber type polarizer cannot meet the requirement of testing accuracy, in addition, the polarization control component is adopted for polarization, the precision can meet the requirement, but the polarization control component has poor stability, the direction of the polarization piece needs to be frequently calibrated, the operation is complicated, the change condition of the polarization crosstalk of the tail fiber cannot be monitored in real time, in addition, the loss of the polarization control component is large, the cost is high, the testing efficiency is low, and the requirement of batch high-efficiency testing is.
SUMMERY OF THE UTILITY MODEL
Therefore, it is necessary to provide a polarizer straight waveguide pigtail polarization crosstalk test system aiming at the technical problems of poor stability, complex operation, large loss of a polarization control assembly, high cost, low test efficiency and being not favorable for realizing the requirement of batch high-efficiency test in the existing waveguide test mode.
The utility model provides a polarizer straight waveguide tail optical fiber polarization crosstalk test system, include: light source, branching unit, polarizer and collection system, the light source passes through the polarization maintaining fiber and is connected with the input of branching unit, the branching unit is equipped with a monitor port, one or more test port, the monitor port passes through the polarization maintaining fiber and is connected with collection system's monitor input, every the test port passes through the polarization maintaining fiber and is connected with a light path input of polarizer, each light path output of polarizer passes through the polarization maintaining fiber and is connected with the input of a device under test, each the output of device under test respectively with collection system's test input is connected.
Further, the polarizer is an array waveguide chip.
Still further, the polarizer includes: the X-cut y-transmission lithium niobate material chip substrate is characterized in that one or more groups of polarizer straight waveguides are arranged on the chip substrate, an isolation groove is cut between every two groups of polarizer straight waveguides, the input end of each group of polarizer straight waveguides is the light path input end, and the output end of each group of polarizer straight waveguides is the light path output end.
Still further, the isolation groove is coated with a light-absorbing substance.
And furthermore, the input end and the output end of the polarizer straight waveguide are coupled by adopting polarization maintaining optical fibers, and the polarizer straight waveguide is an annealed proton exchange polarizer straight waveguide.
The device to be tested is characterized by further comprising a temperature change box for accommodating the device to be tested, each light path output end of the polarizer is inserted into the temperature change box through a polarization maintaining optical fiber and is connected with the input end of one device to be tested, and the output end of each device to be tested penetrates out of the temperature change box and is connected with the test input end of the acquisition device.
Furthermore, the temperature sensor is used for measuring the temperature in the temperature change box, and the output end of the temperature sensor is in communication connection with the temperature input end of the acquisition device.
Furthermore, the collecting device is also provided with a power monitoring port for monitoring the optical power of the test input end and the monitoring input end.
And each test port of the splitter is connected with a light path input end of the polarizer through the polarization maintaining fiber via the flange.
Furthermore, each light path output end of the polarizer and the input end of a device to be tested are subjected to polarization maintaining fusion welding, and the fusion welding angle is 0 degree or 90 degrees.
The utility model discloses a lithium niobate array straight waveguide of single polarization work has broken through the problem that the measuring accuracy is low, inefficiency and with high costs as the polarizer, adopts the multichannel collection appearance in addition, can realize the requirement that multichannel tail optical fiber polarization crosstalk and insertion loss gathered simultaneously.
Drawings
FIG. 1 is a system block diagram of a fiber optic current transformer;
FIG. 2 is a schematic diagram of a straight waveguide structure;
FIG. 3 is a schematic diagram of a system for testing polarization crosstalk of a polarizer straight waveguide pigtail according to the present invention;
FIG. 4 is a schematic diagram of a polarizer structure.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
Fig. 3 shows a schematic diagram of a system for testing polarization crosstalk of a polarizer straight waveguide pigtail of the present invention, which includes: light source 1, branching unit 2, polarizer 3 and collection system 4, light source 1 is connected with the input of branching unit 2 through polarization maintaining fiber, branching unit 2 is equipped with a monitor port, one or more test port, the monitor port passes through polarization maintaining fiber and is connected with collection system 4's monitor input, every the test port passes through polarization maintaining fiber and is connected with a light path input of polarizer 3, each light path output of polarizer 3 passes through polarization maintaining fiber and is connected with the input of a device under test, each the output of device under test respectively with collection system's test input is connected.
Specifically, the depolarized light emitted by the light source 1 is divided into multiple paths by the splitter, wherein preferably, the total path is divided into 16 paths, 01-15 paths are used as test input light, 16 paths are used as monitoring light source stability and calculation reference, 01-15 paths of light output from the splitter 2 enter the polarizer 3, the depolarized light enters the polarizer 3 and becomes single polarization linear polarization, and the single polarization linear polarization is output through the polarization maintaining fiber of the polarizer 3, preferably, the polarization maintaining tail fiber is adopted for output, and is connected with the device 801 and 815 to be tested. The period 801-815 to be tested is preferably a straight waveguide to be tested, and more preferably a titanium diffusion straight waveguide. The straight waveguide output tail fiber to be tested is connected with an automatic acquisition system through an adapter, and polarization crosstalk and insertion loss variation of the tail fiber are acquired in real time.
The utility model discloses a lithium niobate array straight waveguide of single polarization work has broken through the problem that the measuring accuracy is low, inefficiency and with high costs as the polarizer, adopts the multichannel collection appearance in addition, can realize the requirement that multichannel tail optical fiber polarization crosstalk and insertion loss gathered simultaneously.
In one embodiment, the polarizer 3 is an array waveguide chip.
As shown in fig. 4, in one embodiment, the polarizer 3 includes: the X-cut y-transmission lithium niobate material chip substrate 31 is characterized in that one or more groups of polarizer straight waveguides 32 are arranged on the chip substrate 31, an isolation groove 33 is cut between each group of polarizer straight waveguides 32, the input end of each group of polarizer straight waveguides 32 is the light path input end, and the output end of each group of polarizer straight waveguides 32 is the light path output end.
The embodiment realizes the adjustment of the depolarized light of the light source 1 into single polarization linear polarization through the polarizer 3.
In one embodiment, the isolation grooves 33 are coated with a light absorbing material.
This embodiment prevents crosstalk between waveguides by coating a light absorbing substance.
In one embodiment, the input end and the output end of the polarizer straight waveguide 32 are coupled by polarization-maintaining optical fiber, and the polarizer straight waveguide 32 is an annealed proton-exchange polarizer straight waveguide.
The chip of the embodiment adopts the annealing proton exchange straight waveguide, only supports TE mode transmission, adopts polarization maintaining fiber coupling for input and output, and finally can adopt a tube shell to package into a polarizer module, the polarization crosstalk of the tail fiber of the module can reach 38dB and is far higher than the crosstalk value of the test straight waveguide, the test requirement is met, the single loss is only about 1.2dB, and the batch test is convenient to realize.
In one embodiment, the device under test further comprises a temperature change box 5 for accommodating the device under test, each optical path output end of the polarizer 3 is inserted into the temperature change box 5 through a polarization maintaining fiber to be connected with an input end of a device under test, and an output end of each device under test respectively penetrates out of the temperature change box 5 to be connected with a test input end of the acquisition device.
The temperature change box is added in the embodiment, has a high-low temperature circulation function, and can realize constant-speed temperature change.
In one embodiment, the temperature acquisition device further comprises a temperature sensor 6 for measuring the temperature in the temperature change box 5, and the output end of the temperature sensor 6 is in communication connection with the temperature input end of the acquisition device 4.
The temperature sensor is used in the embodiment to record the temperature change condition of the temperature change box in real time.
In one embodiment, the collecting device 4 is further provided with a power monitoring port 41 for monitoring the optical power of the test input and the monitoring input.
In this embodiment, the optical power output by the demultiplexer is monitored through the power monitoring port for reference.
In one embodiment, the optical fiber polarization maintaining device further comprises a flange 7, and each test port of the splitter 2 is connected with an optical path input end of the polarizer 3 through the flange 7 through the polarization maintaining optical fiber.
The embodiment is provided with a flange plate, and light output by the test port of the shunt enters the polarizer through the connecting point of the flange plate.
In one embodiment, each optical path output end of the polarizer 3 is welded to an input end of a device to be tested in an off-axis polarization maintaining manner, and the welding angle is 0 ° or 90 °.
After light output by the test port of the splitter enters the polarizer, the light is output by the polarizer polarization-maintaining tail fiber and is subjected to polarization-maintaining fusion with a device to be tested, and the polarizer and the straight waveguide tail fiber are both fast-axis and fixed-axis, so that when the fusion angle is selected to be 0 degree (90 degrees), a TE (TM) mode is transmitted in the straight waveguide.
As the best embodiment of the present invention, a polarizer straight waveguide pigtail polarization crosstalk testing system, as shown in fig. 3, includes: the device comprises a light source 1, a branching unit 2, a polarizer 3, a collecting device 4, a temperature change box 5 for accommodating a device to be tested, a temperature sensor 6 and a flange 7, wherein the light source 1 is connected with the input end of the branching unit 2 through a polarization maintaining fiber, the branching unit 2 is provided with a monitoring port and one or more testing ports, the monitoring port is connected with the monitoring input end of the collecting device 4 through the polarization maintaining fiber, each testing port is connected with a light path input end of the polarizer 3 through the polarization maintaining fiber via the flange 7, each light path output end of the polarizer 3 is inserted into the temperature change box 5 through the polarization maintaining fiber to be connected with the input end of the device to be tested, each light path output end of the polarizer 3 is in polarization maintaining fusion joint with the input end of the device to be tested, the fusion joint angle is 0 degree or 90 degrees, and the output end of each device to be tested penetrates out of the temperature change box 5 to be, the output end of the temperature sensor 6 is in communication connection with the temperature input end of the acquisition device 4, and the acquisition device 4 is further provided with a power monitoring port 41 for monitoring the optical power of the test input end and the monitoring input end;
the polarizer 3 is an array waveguide chip, and the polarizer 3 comprises: x cuts y and passes lithium niobate material chip substrate 31 be provided with a set of or multiunit polarizer straight waveguide 32 on the chip substrate 31, cut an isolation groove 33 between every group polarizer straight waveguide 32, coating light absorbing material on the isolation groove 33, every group the input of polarizer straight waveguide 32 does the light path input end, every group the output of polarizer straight waveguide 32 does the light path output end, the input and the output of polarizer straight waveguide 32 adopt polarization maintaining fiber 34 coupling, polarizer straight waveguide 32 is annealing proton exchange polarizer straight waveguide, outside encapsulation tube shell 35.
The principle of the light path is as follows: the method comprises the steps that depolarized light emitted by a light source is divided into 16 paths through a splitter, 01-15 paths are used as test input light, 16 paths are used for monitoring the stability of the light source and calculating reference, light output by the 1-15 paths of splitter enters a polarizer through a flange connection point, the depolarized light is changed into single polarization line polarized light after entering the polarizer, the single polarization line polarized light is output through a polarizer polarization maintaining tail fiber and is subjected to polarization maintaining fusion with a device to be tested, the polarizer and a straight waveguide tail fiber are fast-axis and fixed-axis, therefore, when the fusion angle is selected to be 0 degree (90 degrees), a TE (TM) mode is transmitted in a straight waveguide, the straight waveguide output tail fiber is connected with an automatic acquisition system through an adapter, and tail fiber polarization crosstalk and insertion loss variation in a TE (.
Introduction of all the components:
light source 1: SLD high-power depolarization light source, power 10 + -1 mW.
A shunt 2: 1X 16 optical fiber type beam splitter for splitting light.
Polarizer 3: as shown in fig. 4, in the array waveguide chip, 17 straight waveguides are designed on an X-cut y-transmission lithium niobate material, 15 groups of waveguides are used for testing, 2 groups of waveguides are used for standby, an isolation groove is cut between each group of waveguides, and a light absorbing substance is coated on the isolation groove to isolate the waveguides, so that crosstalk between the waveguides is prevented. The chip adopts an annealing proton exchange straight waveguide, only supports TE mode transmission, adopts polarization maintaining fiber coupling for input and output, and finally adopts a tube shell to package into a polarizer module.
The polarizer is made of annealed proton exchange waveguide, and the waveguide made by the process has the function of polarizing (single polarization working state), so that the polarization crosstalk of the tail fiber is high. The insertion loss of the single straight waveguide is 1.2dB, the coupling loss is 0.3 dB/end, the transmission loss is 0.3dB/cm, and the total length is 2cm, so that the total loss is 1.2dB which is 0.3dB multiplied by 2 end plus 0.3dB multiplied by 2 cm. Because the polarization crosstalk of the tail fiber of the module can reach 38dB and is far higher than the crosstalk value of a test straight waveguide, the test requirement is met, the single loss is only about 1.2dB, and the mass test is convenient to realize.
A device to be tested: the titanium diffusion straight waveguide can simultaneously transmit two modes of TE/TM.
Temperature change box 5: has high and low temperature circulation function and can realize constant speed and variable temperature.
Temperature sensor 6: the temperature change condition recording device is used for recording the temperature change condition of the temperature change box in real time.
Power monitor port 41: the optical power at the output of the 16-way splitter is monitored for reference.
The automatic acquisition system 4: and collecting the polarization crosstalk and insertion loss variation of the tail fiber of the device to be tested.
The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.
Claims (10)
1. A polarizer straight waveguide tail fiber polarization crosstalk test system is characterized by comprising: light source (1), branching unit (2), polarizer (3) and collection system (4), light source (1) is connected with the input of branching unit (2) through polarization maintaining fiber, branching unit (2) are equipped with a control port, one or more test port, the control port is connected with the control input of collection system (4) through polarization maintaining fiber, every test port is connected with a light path input of polarizer (3) through polarization maintaining fiber, each light path output of polarizer (3) is connected with the input of a device under test through polarization maintaining fiber, each the output of device under test respectively with collection system's test input is connected.
2. The polarizer straight waveguide pigtail polarization crosstalk test system of claim 1, wherein the polarizer (3) is an array waveguide chip.
3. The polarizer straight waveguide pigtail polarization crosstalk testing system according to claim 2, wherein said polarizer (3) comprises: x cuts lithium niobate material chip base (31) of passing y be provided with a set of or multiunit polarizer straight waveguide (32) on chip base (31), cut an isolation groove (33) between every group polarizer straight waveguide (32), every group the input of polarizer straight waveguide (32) does the light path input, every group the output of polarizer straight waveguide (32) does the light path output.
4. The polarizer straight waveguide pigtail polarization crosstalk testing system of claim 3, wherein said isolation slot (33) is coated with a light absorbing substance.
5. The polarizer straight waveguide pigtail polarization crosstalk test system according to claim 3, wherein the input end and the output end of the polarizer straight waveguide (32) are coupled by polarization-maintaining optical fibers, and the polarizer straight waveguide (32) is an annealed proton-exchange polarizer straight waveguide.
6. The polarizer straight waveguide pigtail polarization crosstalk testing system according to claim 1, further comprising a temperature-variable box (5) for accommodating the device under test, wherein each optical path output end of the polarizer (3) is inserted into the temperature-variable box (5) through a polarization-maintaining optical fiber to be connected with an input end of a device under test, and the output end of each device under test respectively penetrates out of the temperature-variable box (5) to be connected with a test input end of the collecting device.
7. The polarizer straight waveguide pigtail polarization crosstalk testing system according to claim 6, further comprising a temperature sensor (6) for measuring the temperature in the temperature change box (5), wherein the output end of the temperature sensor (6) is in communication connection with the temperature input end of the collecting device (4).
8. Polarizer straight waveguide pigtail polarization crosstalk test system according to claim 1, wherein said harvesting device (4) is further provided with a power monitoring port (41) monitoring the optical power of said test input and said monitoring input.
9. The polarizer straight waveguide pigtail polarization crosstalk testing system according to claim 1, further comprising a flange (7), wherein each of the test ports of the splitter (2) is connected with a light path input end of the polarizer (3) through the flange (7) by a polarization-maintaining fiber.
10. The polarizer straight waveguide tail fiber polarization crosstalk test system according to claim 1, wherein each optical path output end of the polarizer (3) is welded with an input end of a device to be tested in an axis-polarization-maintaining mode, and the welding angle is 0 ° or 90 °.
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| CN201922408642.6U CN211425818U (en) | 2019-12-27 | 2019-12-27 | Polarizer straight waveguide tail fiber polarization crosstalk test system |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112525486A (en) * | 2019-12-27 | 2021-03-19 | 北京世维通科技股份有限公司 | Polarizer straight waveguide tail fiber polarization crosstalk test system |
| RU211908U1 (en) * | 2021-12-09 | 2022-06-28 | Акционерное общество "Российская корпорация ракетно-космического приборостроения и информационных систем" (АО "Российские космические системы") | Airborne X-band irradiator |
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2019
- 2019-12-27 CN CN201922408642.6U patent/CN211425818U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112525486A (en) * | 2019-12-27 | 2021-03-19 | 北京世维通科技股份有限公司 | Polarizer straight waveguide tail fiber polarization crosstalk test system |
| RU211908U1 (en) * | 2021-12-09 | 2022-06-28 | Акционерное общество "Российская корпорация ракетно-космического приборостроения и информационных систем" (АО "Российские космические системы") | Airborne X-band irradiator |
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