CN208174686U - OTDR system for airborne optical fiber avionics network - Google Patents
OTDR system for airborne optical fiber avionics network Download PDFInfo
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- CN208174686U CN208174686U CN201820724858.6U CN201820724858U CN208174686U CN 208174686 U CN208174686 U CN 208174686U CN 201820724858 U CN201820724858 U CN 201820724858U CN 208174686 U CN208174686 U CN 208174686U
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- signal generator
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- optical fiber
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Abstract
The utility model discloses a kind of OTDR systems for airborne optical fiber avionics network, it includes signal generator, coupler, photoswitch, Single Photon Counting device and detector；Signal generator is connect with coupler, and coupler is connected with photoswitch；Coupler connecting detection device, detector are connected with signal generator；Signal generator is connect with Single Photon Counting device；Single Photon Counting device and photoswitch are connected to PC.This system uses Single Photon Counting device, and detection accuracy is higher and can be integrated in a portable unit, is convenient for carrying；And the reliability of this system is higher, guarantees the lasting safety of aircraft.
Description
Technical field
The utility model relates to a kind of OTDR systems for airborne optical fiber avionics network.
Background technique
Fiber optic communication is widely used on latest generation aircraft.Compared to Networks of Fiber Communications, the light of avionics network
Fine length is shorter, connects more complicated.Therefore need dedicated detecting instrument equipment, and fault locator device have it is higher away from
High Resolution guarantees the reliability of system work so as to on-call maintenance replacement.
Utility model content
The purpose of the utility model is to overcome the deficiencies in the prior art, provide that a kind of precision is higher and the use of reliable operation
In the OTDR system of airborne optical fiber avionics network.
The purpose of this utility model is achieved through the following technical solutions：OTDR for airborne optical fiber avionics network
System, it includes signal generator, coupler, photoswitch, Single Photon Counting device and detector；
Signal generator is connect with coupler, and coupler is connected with photoswitch；
Coupler connecting detection device, detector are connected with signal generator；
Signal generator is connect with Single Photon Counting device；
Single Photon Counting device and photoswitch are connected to PC.
It is preferred that signal generator includes pulse laser generation module, synchronised clock module and level conversion mould
Block；
Pulse laser generation module is connect with coupler；Synchronised clock module and level switch module and time correlation monochromatic light
Sub-count device is connected；Detector is connect with level switch module.
It is preferred that detector is single-photon detector.
It is preferred that being provided with adjustable optical attenuator between signal generator and coupler.
It is preferred that signal generator includes FPGA, radio frequency triode and vertical cavity surface emitting laser.
The utility model has the beneficial effects that：This system use Single Photon Counting device, detection accuracy it is higher and
It can be integrated in a portable unit, be convenient for carrying；And the reliability of this system is higher, guarantees the lasting peace of aircraft
Entirely.
Detailed description of the invention
Fig. 1 is the structural schematic diagram of the utility model；
Fig. 2 is the partial structural diagram of the utility model signal generator.
Specific embodiment
The technical solution of the utility model, but the protection scope of the utility model are described in further detail with reference to the accompanying drawing
It is not limited to as described below.
According to OTDR (optical time domain reflectometer, Rayleigh scattering and Fresnel reflection institute when being transmitted in a fiber using light
The optoelectronic integration instrument of the backscattering of generation and manufactured precision, it is widely used in the maintenance of lightguide cable link, construction
Among, the measurement of fiber lengths, the transmission attenuation of optical fiber, connector decaying and fault location etc. can be carried out.) principle, detection point
Resolution and positioning accuracy are inversely proportional with the width of direct impulse, and pulse is narrower, and detection accuracy is higher；On the other hand, OTDR
In system for optical fibre fault monitoring reversed Rayleigh scattering and Fresnel reflection signal power be again with the width of pulse at
Direct ratio, pulse is narrower, and the power of scattered signal is smaller, and the difficulty of detection is bigger (dynamic range is lower).So, it just makes
At the contradiction of positioning accuracy and detectivity in OTDR system.More specifically, it is carried out using traditional optical detector
OTDR fault location, in order to improve the bandwidth that positioning accuracy needs to increase detector, meanwhile, in the certain situation of noise factor
Under, its sensitivity can be reduced again while increasing detector bandwidth.Also, the temperature drift of detector, change in gain and its
The influence of its environmental factor also will affect detection result.Therefore, under above-mentioned limitation, using the OTDR of traditional analog optical detector
The incident optical fiber spot placement accuracy that equipment carries out avionics network is extremely difficult to rice or less.
As shown in Figure 1, be used for the OTDR system of airborne optical fiber avionics network, it includes that signal generator, coupler, light are opened
Pass, Single Photon Counting device and detector；
Signal generator is connect with coupler, and coupler is connected with photoswitch；
Coupler connecting detection device, detector are connected with signal generator；
Signal generator is connect with Single Photon Counting device；
Single Photon Counting device and photoswitch are connected to the mainboard of PC, and PC includes display or display screen.
In a preferred embodiment, signal generator includes pulse laser generation module, synchronised clock module and level
Conversion module；
Pulse laser generation module is connect with coupler；Synchronised clock module and level switch module and time correlation monochromatic light
Sub-count device is connected；Detector is connect with level switch module.
In a preferred embodiment, detector is single-photon detector.
In a preferred embodiment, adjustable optical attenuator is provided between signal generator and coupler.
In a preferred embodiment, as shown in Fig. 2, signal generator includes FPGA, radio frequency triode and vertical cavity surface
Emitting laser.
In a preferred embodiment, to signal generator, single-photon detector and Single Photon Counting device
Parameter is defined.
Signal generator or impulse generator：
According to performance requirement, index that the signal generator or impulse generator used in this system need to meet for：
1) central wavelength：850nm(700-900nm)；
2) pulse width：<1ns；
3) pulse peak power：>=100mW；
4) repetition rate：0.5MHz --- 10MHz is adjustable；
5) operating temperature range：-20℃——+40℃
Single-photon detector：
According to performance requirement, index that the single-photon detector used in this system need to meet for：
1) sensitivity：850nm wavelength attachment photon efficiency is greater than 50%；
2) dark counting：<1000cps；
3) operating temperature range：-20℃——40℃；
4) time jitter：<500ps；
Single Photon Counting device：
According to performance requirement, index that the time correlation photon counter used in this system need to meet for：
1) temporal resolution：<100ps；
2) storage depth is counted：>32bits；
3) synchronization signal rate：0.5MHz --- 10MHz (consistent with impulse generator)
Time correlation photon counting principle is a kind of method of atomic weak light detection.SPDA detector for photon counting
It is high to the responsiveness of incident photon under Geiger mode, it might even be possible to influence single incident photon, be very suitable to reversed
The reception and detection of Rayleigh scattering and Fresnel reflection signal.On the other hand, time correlation photon counting principle utilizes low-light
The naturally discrete feature of lower photon detector output electric signal is penetrated, using pulse screening techniques sum number word counting techniques, and tradition
Analog detection technology compare the analog bandwidth of detector required to substantially reduce.Therefore, former using time correlation photon counting
Reason construction TCS PC-OTDR equipment, can solve the contradiction of positioning accuracy and detectivity that traditional OTDR faces, reaches li
The detection resolution and positioning accuracy of rice magnitude, to meet the application demand of avionics optical-fiber network.
The principle of this system is described below：
OTDR mainly realize when being transmitted in a fiber using laser pulse by caused Rayleigh scattering and Fresnel reflection
's.By the intensity and the time difference that detect the optical signal returned from tested optical fiber, so that it may be calculated according to flight time telemetry
The position of outgoing event point, formula are：
In formula, c is the light velocity in vacuum, and Δ t is that the two-way time of the round-trip case point of light pulse is poor, and n is testing fiber
Refractive index.
As shown in Figure 1, signal generator (signal generator) is integrated with three functional modules：Pulse laser
The setting and generation of (pulsed lasers), the output of synchronised clock (synchronizing clock) and Transistor-Transistor Logic level arrive
The conversion (level transfer) of NIM level.Signal generator generates narrow laser pulse according to setting, is input to coupler
(coupler) then 1 port is output to 1 × 32 photoswitch (switch) by 2 ports, photoswitch then can be according to being switched
Access will be in impulses injection to corresponding tested optical fiber (Fiber Under Test, FUT).When pulsed light transmits in a fiber
The backward return light generated passes through 3 ports of coupler, is detected by single-photon detector.Test show the performance of laser by
The influence of reflected light is unobvious, therefore optoisolator is not added after coupler.The pulse of single-photon detector output is TTL letter
Number, it being mismatched with the NIM incoming level of TCSPC circuit requirement, needing level conversion just to can access after NIM level signal.Together
When TCSPC circuit clock sync signal generated by signal generator, guarantee accurate measurement initial time.In order to realize dim light
Detection, we are added adjustable optical attenuator (Variable Optical Attenuator, VOA) in laser output, prevent
Laser pulse power causes greatly very much the counting of detector to be saturated.By from TCSPC circuit extraction data, and using the shape of histogram
Formula is handled, then can set up the time and correspond to the accumulative experimental result of number of photons, then be converted time coordinate by formula (1)
For length coordinate, to draw out the single photon OTDR curve of tested optical fiber.Different case points different abscissas in curve
Place reflects, and the minimum range between adjacent distinguishable case point is the spatial resolution of single photon OTDR system；By dividing
Analyse the features such as decaying, the reflection peak in curve, so that it may diagnose to tested optical fiber and connector.
Fig. 2 is gain switch light pulse production principle scheme.FPGA reads clock information, generates synchronizing clock signals and use
In the narrow spaces digital signal level of control radio frequency triode (RF transistor).Radio frequency triode generates hundred picoseconds
Pulse current, drive 850nm wave band vertical cavity surface emitting laser (Vertical Cavity Surface Emitting
Laser, V CSEL), and then pass through the laser pulse of gain switch process generation 850nm.
It will be all integrated into reinforced notebook docking station in process of production, be internally integrated functional module, external interface
Including 32 core fibre air plugs and power interface.Laptop rated power is fixed, and realizes the TCSPC-OTDR function of superhigh precision
Energy power consumption is very big, and single laptop is unable to satisfy overall power.Notebook mainboard and docking station internal module can be used at present
The scheme powered respectively.The operating temperature of laser is 10 DEG C~30 DEG C, and the operating temperature of system requirements is -20 DEG C~40
DEG C, temperature control modules can be added inside docking station allows laser and detector to work under the conditions of wide temperature.At present may be used
The function is realized using according to the TEC module of current direction and the change control temperature change of size.
The above is only the preferred embodiment of the utility model only, is not intended to limit the utility model, and should refer to
Out, any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention etc. should all include
It is within the protection scope of the utility model.
Claims (5)
1. being used for the OTDR system of airborne optical fiber avionics network, it is characterised in that：It includes that signal generator, coupler, light are opened
Pass, Single Photon Counting device and detector；
Signal generator is connect with coupler, and coupler is connected with photoswitch；
Coupler connecting detection device, detector are connected with signal generator；
Signal generator is connect with Single Photon Counting device；
Single Photon Counting device and photoswitch are connected to PC.
2. the OTDR system according to claim 1 for airborne optical fiber avionics network, it is characterised in that：Signal generator
Including pulse laser generation module, synchronised clock module and level switch module；
Pulse laser generation module is connect with coupler；Synchronised clock module and level switch module and time correlation single photon meter
Number device is connected；Detector is connect with level switch module.
3. the OTDR system according to claim 1 for airborne optical fiber avionics network, it is characterised in that：Detector is single
Photon detector.
4. the OTDR system according to claim 1 or 2 or 3 for airborne optical fiber avionics network, it is characterised in that：Signal
Adjustable optical attenuator is provided between generator and coupler.
5. the OTDR system according to claim 1 for airborne optical fiber avionics network, it is characterised in that：Signal generator
Including FPGA, radio frequency triode and vertical cavity surface emitting laser.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820724858.6U CN208174686U (en) | 2018-05-16 | 2018-05-16 | OTDR system for airborne optical fiber avionics network |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820724858.6U CN208174686U (en) | 2018-05-16 | 2018-05-16 | OTDR system for airborne optical fiber avionics network |
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| Publication Number | Publication Date |
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| CN208174686U true CN208174686U (en) | 2018-11-30 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109831248A (en) * | 2019-03-01 | 2019-05-31 | 成都成电光信科技股份有限公司 | The synthesis optical fiber inspection device and method of integrated FC optical fiber link and Network Check |
-
2018
- 2018-05-16 CN CN201820724858.6U patent/CN208174686U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109831248A (en) * | 2019-03-01 | 2019-05-31 | 成都成电光信科技股份有限公司 | The synthesis optical fiber inspection device and method of integrated FC optical fiber link and Network Check |
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