Method for testing integrated optical device for front optical path of fiber-optic gyroscope

Abstract

The invention relates to an integrated optical device testing method for a front optical path of a fiber-optic gyroscope, a testing system comprises a first optical fiber coupler, a second optical fiber coupler, an optical fiber reflector, a spectrum analyzer, an optical power meter, an extinction ratio tester and a voltmeter, and light to be tested enters the optical fiber reflector and the second optical fiber coupler after being split by the first optical fiber coupler; and the second optical fiber coupler is respectively connected with the spectrum analyzer, the optical power meter and the extinction ratio tester. After the integrated optical device is electrified, the optical wavelength, the spectral width and the extinction ratio of the integrated optical device can be directly obtained according to the readings of the spectrum analyzer and the extinction ratio tester. Besides, part of light is returned by the optical fiber reflector and then returns to the integrated optical device through the first optical fiber coupler, and the output optical power value and the optical responsivity value of the integrated optical device can be calculated according to the reading of the voltmeter, the reading of the optical power meter, the inherent insertion loss value of the optical fiber coupler and the inherent return loss value of the optical fiber reflector.

Description

Technical Field

[0001] The invention belongs to the field of optical fiber sensing testing, and in particular relates to a method for testing an integrated optical device for a front optical path of an optical fiber gyroscope. Background Art

[0002] The integrated optical device for the front optical path of the fiber optic gyroscope (hereinafter referred to as the integrated optical device) is mainly used for the integrated fiber optic gyroscope. The integrated optical device contains SLD light emitting diodes, optical lenses, Peltier coolers, PD photodiodes, amplifier circuits and optical fiber components. It has the functions of light emission, light coupling / splitting and light detection, and can replace the three devices of SLD light source, fiber coupler and photodetector assembly in the traditional fiber optic gyroscope.

[0003] Among them, the SLD light-emitting diode can output a DC optical signal under the drive of an external current. Part of the light is transmitted through the optical lens, coupled into the optical fiber component, and transmitted to the fiber optic gyroscope through the optical fiber. The signal light returned from the fiber optic gyroscope enters the same optical fiber of the integrated optical device, and part of the light is reflected at the optical lens, entering the PD photodiode, undergoing photoelectric conversion, generating a current signal, which is amplified by the amplifier circuit and converted into a voltage signal for output.

[0004] The optical wavelength, spectral width, extinction ratio, output optical power and photoresponsivity of integrated optical devices are key indicators that significantly affect the performance of fiber optic gyroscopes and the reliability of the device itself, and need to be screened and tested before installation. The existing technology requires the pigtails of integrated optical devices to be inserted into a spectrum analyzer, an optical power meter and an extinction ratio tester to test the corresponding parameter values. In addition, it is necessary to connect the optical fiber to an additional light source device to test the photoresponsivity value, which is cumbersome and inefficient. Summary of the invention

[0005] The purpose of the present invention is to provide a method for testing integrated optical devices for the front optical path of a fiber optic gyroscope. By designing a combined test system and a corresponding calculation method, it is achieved that only one fiber fusion test is performed to obtain multiple indicators such as the optical wavelength, spectral width, extinction ratio, output optical power value and optical response value of the integrated optical device, thereby improving the screening test efficiency in the actual production process.

[0006] Another object of the present invention is to provide an integrated optical device testing system for the front optical path of a fiber optic gyroscope.

[0007] The above-mentioned purpose of the present invention is mainly achieved through the following technical solutions:

[0008] A method for testing an integrated optical device for a front optical path of a fiber optic gyroscope is provided. The method adopts a combined test system for testing. The combined test system comprises a first fiber coupler, a second fiber coupler, a fiber reflector, a spectrum analyzer, an optical power meter, an extinction ratio tester and a voltmeter. One end of the first fiber coupler is connected to the integrated optical device to be tested, and the other end is respectively connected to the second fiber coupler and the fiber reflector; one end of the second fiber coupler is connected to the first fiber coupler, and the other end is respectively connected to the spectrum analyzer, the optical power meter and the extinction ratio tester. The electrical output pin of the integrated optical device to be tested is connected to the voltmeter. The specific test method comprises the following steps:

[0009] (1) After the integrated optical device is powered on, the output optical signal enters the first optical fiber coupler. Part of the optical signal reaches the spectrum analyzer, optical power meter and extinction ratio tester through the second optical fiber coupler, and the remaining optical signal enters the optical fiber reflector. The optical fiber reflector returns part of the light, and then returns to the integrated optical device through the first optical fiber coupler. The optical wavelength λ and spectrum width △λ measured by the spectrum analyzer, the reading P of the optical power meter, the reading PER of the extinction ratio tester and the reading U1 of the voltmeter are recorded. The optical wavelength λ output by the integrated optical device is DUT =λ, the spectral width △λ output by the integrated optical device DUT =△λ, extinction ratio PER of integrated optical devices DUT =PER;

[0010] (2) Calculate the output optical power value P of the integrated optical device according to the measurement result of step (1) DUT , the calculation formula is as follows:

[0011] P DUT =P+IL 12 +IL 46

[0012] Among them: IL 12 The intrinsic insertion loss value of the first fiber coupler connecting the integrated optical device port to the second fiber coupler port, IL 46 an intrinsic insertion loss value of the second optical fiber coupler connecting the first optical fiber coupler port to the port connected to the optical power meter;

[0013] (3) P obtained according to step (2) DUT Calculate the optical power value returned to the integrated optical device using the following formula:

[0014] P in =P DUT -2×IL 13 -RL

[0015] Among them: IL 13is the intrinsic insertion loss value of the first optical fiber coupler from the port connected to the integrated optical device to the port connected to the optical fiber reflector, and RL is the intrinsic return loss value of the optical fiber reflector;

[0016] (4) Disconnect the integrated optical device pigtail from the port 1 of the test device, and perform a reflection elimination process at the end of the integrated optical device pigtail. Record the voltage meter reading U0, and calculate the optical responsivity value R of the integrated optical device according to the optical power value in step (3). e , the calculation formula is as follows:

[0017]

[0018] The first optical fiber coupler, the second optical fiber coupler and the optical fiber reflector are connected by welding using a welding machine.

[0019] One end of the second optical fiber coupler includes three ports 5, 6, and 7, and the connection methods of ports 5, 6, and 7 with the spectrum analyzer, optical power meter, and extinction ratio tester are as follows: ports 5, 6, and 7 of the second optical fiber coupler are fusion-spliced ​​with FC / APC single-mode optical fiber jumpers, and the FC / APC connectors of ports 5, 6, and 7 are respectively inserted into the spectrum analyzer, optical power meter, and extinction ratio tester.

[0020] The integrated optical device is connected to the first optical fiber coupler as follows: the first optical fiber coupler is connected to the port of the integrated optical device to reserve about 1 meter of bare optical fiber, and the integrated optical device pigtail is fused with the bare optical fiber of port 1.

[0021] An integrated optical device test system for a front optical path of a fiber optic gyroscope comprises a first fiber optic coupler, a second fiber optic coupler, a fiber optic reflector, a spectrum analyzer, an optical power meter, an extinction ratio tester and a voltmeter, wherein:

[0022] The first fiber coupler receives the optical signal of the integrated optical device to be tested, and outputs the optical signal to the second fiber coupler and the fiber reflector respectively, and receives the optical signal returned by the fiber reflector, and outputs the optical signal to the integrated optical device to be tested;

[0023] The second optical fiber coupler receives the optical signal of the first optical fiber coupler and outputs the optical signal to the optical spectrum analyzer, the optical power meter and the extinction ratio tester respectively;

[0024] The optical fiber reflector receives the optical signal input by the first optical fiber coupler and returns part of the optical signal to the first optical fiber coupler;

[0025] A spectrum analyzer, used to measure the wavelength and spectrum width of the received optical signal;

[0026] An optical power meter is used to measure the optical power value of the received optical signal;

[0027] Extinction ratio tester, used to measure the extinction ratio of the received optical signal;

[0028] A voltmeter is used to measure the voltage value of the integrated optical device to be tested.

[0029] It also includes a casing, in which the first optical fiber coupler, the second optical fiber coupler, the optical fiber reflector and the optical fiber connecting the above devices are arranged.

[0030] Compared with the prior art, the present invention has at least the following beneficial effects:

[0031] The present invention tests the structure of the testing system and only requires one fusion test to obtain the optical wavelength, spectral width, extinction ratio, output optical power, photoresponsivity and other parameter values ​​of the integrated optical device, thereby avoiding multiple access tests and being easy to operate, efficient and fast. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram for integrated optical device testing. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0034] like Figure 1 The figure shows the test principle diagram of integrated optical devices. The first fiber coupler has one input port and two output ports. Light is input from port 1 and output from ports 2 and 3 after being split. The corresponding intrinsic insertion loss values ​​are IL 12 and IL 13 , its spectral bandwidth is greater than the spectral width output by the integrated optical device, and the absolute value of polarization crosstalk is greater than the extinction ratio of the integrated optical device.

[0035] The second fiber coupler has one input port and three output ports. The light output from port 2 of the first fiber coupler enters port 4 of the second fiber coupler and is output from ports 5, 6, and 7 after being split. The corresponding inherent insertion loss values ​​are IL 45 , I.L. 46 , I.L. 47 , its spectral bandwidth is greater than the spectral width output by the integrated optical device, and the absolute value of polarization crosstalk is greater than the extinction ratio of the integrated optical device.

[0036] The fiber reflector can reflect light back, and its inherent return loss value is RL. The light output from the first fiber coupler port 3 enters the fiber reflector, returns to the first fiber coupler port 3 after reflection, and then outputs from port 1, and finally returns to the integrated optical device as the input light of the integrated optical device.

[0037] The specific test method includes the following steps:

[0038] (1) After the integrated optical device is powered on, the output optical signal enters the first fiber coupler, enters the second fiber coupler through port 2, and then reaches the spectrum analyzer, optical power meter and extinction ratio tester, and enters the fiber reflector through port 3. The fiber reflector returns part of the light, and then returns to the integrated optical device through the first fiber coupler. The measurement results of the spectrum analyzer, optical power meter, extinction ratio tester and voltmeter are recorded;

[0039] (2) Calculate the output optical power value P of the integrated optical device according to the measurement result of step (1) DUT , in dBm, is calculated as follows:

[0040] P DUT =P+IL 12 +IL 46

[0041] Where: P is the reading of the optical power meter in dBm; IL 12 The intrinsic insertion loss value from port 1 to port 2 of the first optical fiber coupler, in dB, IL 46 is the intrinsic insertion loss value from port 4 to port 6 of the second optical fiber coupler, in dB;

[0042] (3) Calculate the optical power value P returned to the integrated optical device in , in dBm, is calculated as follows:

[0043] P in =P DUT -2×IL 13 -RL

[0044] Where: P DUT is the output optical power value of the integrated optical device, in dBm, calculated in step (2); IL 13 is the intrinsic insertion loss value of the first fiber coupler from port 1 to port 3, in dB; RL is the intrinsic return loss value of the fiber reflector, in dB.

[0045] (4) Disconnect the integrated optical device pigtail from port 1 of the test device, perform a reflection elimination process at the end of the integrated optical device pigtail, record the voltage value of the voltmeter, and calculate the optical responsivity value R of the integrated optical device based on the measurement results. e , the unit is V / μW, and the calculation formula is as follows:

[0046]

[0047] Where: U1 is the voltage meter reading measured in step (1), in V; U0 is the voltage meter reading measured in step (4), in V; Pin To return the optical power value entering the integrated optical device, in μW, calculated in step (3) and converted into absolute optical power.

[0048] (5) In step (1), the spectrum analyzer measures the wavelength λ of the 5-port output light and the spectrum width

[0049] △λ, since the spectral bandwidth of the fiber coupler is greater than the spectral width of the output light of the integrated optical device, the wavelength of the light output by the integrated optical device is λ DUT =λ, the spectral width △λ output by the integrated optical device DUT =△λ; the extinction ratio tester measures the extinction ratio PER of the output light of the 7 ports. Since the absolute value of the polarization crosstalk of the fiber coupler is greater than the extinction ratio of the output light of the integrated optical device, the extinction ratio PER of the integrated optical device DUT =PER.

[0050] Example 1

[0051] A 1310nm band 1×2 fiber coupler, a 1×3 fiber coupler and a fiber reflector are selected. The inherent insertion loss value IL between port 1 to ports 2 and 3 of the 1×2 fiber coupler is 12 IL 13 They are 3.20dB and 3.37dB respectively, the spectral bandwidth is 80nm, and the absolute value of polarization crosstalk is 14dB; the inherent insertion loss value IL between the 4th port and the 5th, 6th, and 7th ports of the 1×3 fiber coupler 45 IL 46 IL 47 They are 5.25dB, 4.87dB, and 5.36dB respectively, the spectral bandwidth is 80nm, and the absolute value of polarization crosstalk is 12dB; the inherent return loss value RL of the fiber optic reflector is 13.01dB, that is, the reflectivity is 5.0%.

[0052] Two fiber couplers and a fiber reflector are spliced ​​with a splicer, and ports 5, 6, and 7 are spliced ​​with FC / APC single-mode fiber jumpers. The loss value of each splicing point is less than 0.01dB, and the loss value of the splicing point can be ignored in subsequent calculations.

[0053] The first fiber coupler, the second fiber coupler, the fiber reflector and the optical fiber connecting the above devices are fixed in a housing to form a test device. Port 1 reserves about 1 meter of bare optical fiber, and the FC / APC connectors of ports 5, 6, and 7 are respectively inserted into the spectrum analyzer, optical power meter and extinction ratio tester to build a fixed test system.

[0054] The integrated optical device pigtail is fused with port 1 of the test device, and the fusion loss is less than 0.01dB. The output pin of the integrated optical device is connected to a voltmeter.

[0055] A set of test software was developed to control each instrument to perform test operations. The software collected the readings of the spectrum analyzer, λ, which was 1305.6nm, △λ, which was 35.6nm, the optical power meter reading, P, which was -12.01dBm, the extinction ratio tester reading, PER, which was 0.8dB, and the voltmeter reading, U1, which was -0.817V.

[0056] Disconnect the integrated optical device pigtail from the port 1 of the test device (point C in the figure), and perform a reflection elimination process at the end of the integrated optical device pigtail so that no light enters the integrated optical device. At this time, the software collects the voltage meter reading U0 as -1.657V. Finally, the software automatically calculates the wavelength λ of the output light of the integrated optical device according to the formula DUT 1305.6nm, spectral width △λ DUT 35.6nm, extinction ratio PER DUT is 0.8dB, output optical power value P DUT The light response value is -3.94dBm and R e It is 0.196V / μW.

[0057] The above description is only the best specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

[0058] The contents not described in detail in the specification of the present invention belong to the common knowledge of professionals in the field.

Claims

1. A method for testing integrated optical devices for the front optical path of a fiber optic gyroscope, characterized in that: A combined test system is used for detection, the combined test system includes a first fiber coupler, a second fiber coupler, a fiber reflector, a spectrum analyzer, an optical power meter, an extinction ratio tester and a voltmeter, one end of the first fiber coupler is connected to the integrated optical device to be tested, and the other end is respectively connected to the second fiber coupler and the fiber reflector; one end of the second fiber coupler is connected to the first fiber coupler, and the other end is respectively connected to the spectrum analyzer, the optical power meter and the extinction ratio tester, and the electrical output pin of the integrated optical device to be tested is connected to the voltmeter. The specific test method includes the following steps: (1) After the integrated optical device is powered on, the output optical signal enters the first optical fiber coupler. Part of the optical signal reaches the spectrum analyzer, optical power meter and extinction ratio tester through the second optical fiber coupler, and the remaining optical signal enters the optical fiber reflector. The optical fiber reflector returns part of the light, and then returns to the integrated optical device through the first optical fiber coupler. The optical wavelength λ and spectrum width △λ measured by the spectrum analyzer, the reading P of the optical power meter, the reading PER of the extinction ratio tester and the reading U1 of the voltmeter are recorded. The optical wavelength λ output by the integrated optical device is DUT =λ, the spectral width △λ output by the integrated optical device DUT =△λ, extinction ratio PER of integrated optical devices DUT =PER; (2) Calculate the output optical power value P of the integrated optical device according to the measurement result of step (1) DUT , the calculation formula is as follows: P DUT =P+IL 12 +IL 46 Among them: IL 12 The intrinsic insertion loss value of the first fiber coupler connecting the integrated optical device port to the second fiber coupler port, IL 46 an intrinsic insertion loss value of the second optical fiber coupler connecting the first optical fiber coupler port to the port connected to the optical power meter; (3) P obtained according to step (2) DUT Calculate the optical power value P returned to the integrated optical device in , the calculation formula is as follows: P in =P DUT -2×IL 13 -RL Among them: IL 13 is the intrinsic insertion loss value of the first optical fiber coupler from the port connected to the integrated optical device to the port connected to the optical fiber reflector, and RL is the intrinsic return loss value of the optical fiber reflector; (4) Disconnect the integrated optical device pigtail from the port 1 of the test device, and perform a reflection elimination process on the end of the integrated optical device pigtail. Record the voltage meter reading U0. According to step (3), the optical power value P in Calculating the photoresponsivity value R of integrated optical devices e , the calculation formula is as follows:

2. A method for testing integrated optical devices for the front optical path of a fiber optic gyroscope according to claim 1, characterized in that: The first optical fiber coupler, the second optical fiber coupler and the optical fiber reflector are connected by welding using a welding machine.

3. The method for testing an integrated optical device for the front optical path of a fiber optic gyroscope according to claim 1, characterized in that: One end of the second optical fiber coupler includes three ports 5, 6, and 7, and the connection methods of ports 5, 6, and 7 with the spectrum analyzer, optical power meter, and extinction ratio tester are as follows: ports 5, 6, and 7 of the second optical fiber coupler are fusion-spliced ​​with FC / APC single-mode optical fiber jumpers, and the FC / APC connectors of ports 5, 6, and 7 are respectively inserted into the spectrum analyzer, optical power meter, and extinction ratio tester.

4. The method for testing an integrated optical device for a front optical path of a fiber optic gyroscope according to claim 1, characterized in that: The integrated optical device is connected to the first optical fiber coupler as follows: the first optical fiber coupler is connected to the port of the integrated optical device to reserve about 1 meter of bare optical fiber, and the integrated optical device pigtail is fused with the bare optical fiber of port 1.

5. An integrated optical device test system for the front optical path of a fiber optic gyroscope, characterized in that: The device comprises a first optical fiber coupler, a second optical fiber coupler, an optical fiber reflector, an optical spectrum analyzer, an optical power meter, an extinction ratio tester and a voltmeter, wherein: The first fiber coupler receives the optical signal of the integrated optical device to be tested, and outputs the optical signal to the second fiber coupler and the fiber reflector respectively, and receives the optical signal returned by the fiber reflector, and outputs the optical signal to the integrated optical device to be tested; The second optical fiber coupler receives the optical signal of the first optical fiber coupler and outputs the optical signal to the optical spectrum analyzer, the optical power meter and the extinction ratio tester respectively; The optical fiber reflector receives the optical signal input by the first optical fiber coupler and returns part of the optical signal to the first optical fiber coupler; A spectrum analyzer, used to measure the wavelength and spectrum width of the received optical signal; An optical power meter is used to measure the optical power value of the received optical signal; Extinction ratio tester, used to measure the extinction ratio of the received optical signal; A voltmeter is used to measure the voltage value of the integrated optical device to be tested.

6. The integrated optical device test system for the front optical path of a fiber optic gyroscope according to claim 5, characterized in that: It also includes a casing, in which the first optical fiber coupler, the second optical fiber coupler, the optical fiber reflector and the optical fiber connecting the above devices are arranged.

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