The DVS/DAS Integrated Optical Module is internally designed with a coherent detection optical path for very high sensitivity and signal-to-noise ratio.
YB Photonics’s DVS/DAS integrated optical module highly integrates inside our own proprietary ultra-narrow linewidth laser, pulsed EDFA, Raman amplifier, AOM and other optical components in single compact package.
DAS/DVS integrated module integrates ultra-narrow linewidth light source, AOM acousto-optic modulator, AOM driver, pulsed EDFA, optical circulator, Raman amplifier, coherent receiver module, etc., which only needs to be paired with a high-speed data acquisition card to form a set of DAS Distributed Acoustic Wave (DVS Distributed Vibration) measurement system.
The module is highly integrated, small in size, and adopts independent intellectual property rights of coherent receiver module, which has the characteristics of high signal-to-noise ratio of coherent detection and increases the sensing distance of distributed fiber optic acoustic wave sensing system.
The module is specially designed for distributed fiber optic acoustic wave sensing, perimeter security equipment vendors to provide high-quality supporting products and solutions.
Key Parameters
We use this module with 250M sample rate DAQ card to realize the DAS system parameters (for reference)
Parameter Name | Parameter Value | Note |
---|---|---|
Maximum actual monitoring distance (without Raman) | 25km | Refers to the correct frequency at which a single-frequency sound wave can be demodulated at the furthest end |
Maximum actual monitoring distance (with Raman) | 50km | |
Laser Pulsewidth | 50ns-500ns | When using 80M AOM by default |
Maximum time sampling resolution | 4ns | Maximum sampling bandwidth of capture card with 250M sampling rate |
Highest spatial sampling resolution | 0.4m | |
Lower analog bandwidth limit for a single sensor at 40km | 5Hz | |
Analog bandwidth limit for a single sensor at 40km | 1000Hz | |
Range of spatial response to a single point of knock on the fiber at 40 km (i.e., the true spatial resolution of the system at the input of the shock function) | 10m | |
Spatial positioning accuracy for a single point knock on the fiber at 40km | 2m | Excitation at a point of the fiber, the monitoring system detects the positioning accuracy at the location of the excitation |
What is the frequency accuracy of the sinusoidal input at 40km for a single point on the fiber with a length of 10 meters of fiber? | 1Hz | Frequency range in which the excitation signal is received at the farthest end of the fiber and can be correctly demodulated at the longest monitoring distance |
Module parameters | Min. | Type. | Max. | Unit | Notes |
---|---|---|---|---|---|
Measuring Distance | 60 | km | |||
pulse width | 50 | 500 | ns | ||
preheating time | <5 | Min | |||
operating voltage | 23 | 25 | V | ||
Power | 12 | 13 | 18 | W | |
operating temperature | -20 | 60 | ℃ | ||
Storage temperature | -30 | 70 | ℃ | ||
communications interface | Serial TTL | ||||
communications protocol | Modbus-RTU | ||||
Ultra-narrow linewidth light source | Min. | Type. | Max. | Unit | Notes |
operating wavelength | 1530 | 1550 | 1570 | nm | |
output power | 10 | 13 | dBm | ||
line width | <3 | kHz | |||
relative intensity noise | <120 | dB/Hz | |||
wavelength drift | ±1 | pm | |||
power stability | ±2% | ||||
Side mode rejection ratio | 60 | dB | |||
Pulsed EDFA | Min. | Type. | Max. | Unit | Notes |
Operating wavelength range | 1550.12 | nm | |||
Input peak optical power | 10 | dBm | |||
Input average optical power | -35 | -30 | dBm | ||
Output peak optical power | 23 | dBm | |||
Output average optical power | 0 | dBm | |||
repetition rate | 100 | kHz | |||
coefficient of noise | 5.5 | dB | |||
Polarization Related Gain | 0.5 | dB | |||
polarization mode dispersion | 0.5 | ps | |||
AOM | Min. | Type. | Max. | Unit | Notes |
Operating wavelength range | 1520 | 1550 | 1580 | nm | |
Average optical power | 0.5 | W | |||
Maximum pulsed light power | 0.5 | kW | |||
insertion loss | 2.5 | 3 | dB | ||
extinction ratio | 50 | dB | |||
Rise/fall time | 30 | ns | |||
frequency | 80 | MHz | |||
standing wave ratio (physics) | 1.2:1 | ||||
Input Impedance | 50 | Ω | |||
RF power | 2.5 | W | |||
frequency shift | 80 | MHz | customizable | ||
Balance detector | Min. | Type. | Max. | Unit | Notes |
bandwidths | 200 | MHz | |||
gain (electronics) | 50 | kV/A | |||
NEP | 30 | pW/Sqrt(Hz) |
Product category | Detection distance | Number of channels | AOM frequency shift |
---|---|---|---|
GY-DAS-V3: DAS integrated module | 40:40km | 1:1 channel | Integrated 80M AOM(Default) |
GY-DVS-V3: DVS integrated module | 2:2 channel | A200:Integrated 200M AOM |
Q:1、DVS and DAS, what is the difference between them?
A: dvs is a qualitative measurement, detecting vibration by amplitude, but amplitude and vibration are not linear, das is phase demodulation, the demodulated phase is completely linear with vibration and can completely recover the vibration or sound signal. In YB Photonics modules, you need to specify DVS or DAS module when placing an order because there is a difference in the internal implementation of these two modules; the DVS module does the de-enveloping process after the BPD, while the DAS module outputs the signal from the BPD directly.
Open the product box and check against the table below to make sure the following accessories are included, if any are missing, please contact us promptly.
Name | Quantities |
---|---|
DAS/DVS integrated module | 1pcs |
24V Power Module | 1pcs |
USB to TTL Module | 1pcs |
SMA RF Cable | 3pcs |
Product Test Report | 1pcs |
Certificate of Conformity | 1pcs |
User's Manual | 1pcs |
The DAS/DVS integration module interfaces are defined in the following table:
Interface Type | Silkscreen | Clarification |
---|---|---|
Plug-in terminals | 24V | DC power supply +24V supply |
GND | DC power supply GND | |
Plug-in terminals | TTL | Serial, TTL Level |
SMA | AOM | AOM modulated signal input |
Optical interface | Sensor1 | Sensing fiber 1, default FC/APC connector, single-channel products use this interface |
Optical interface | Sensor2 | Connect to sensing fiber 2, default FC/APC connector |
SMA | OUT1 | Module channel 1 output voltage signal, single-channel products use this interface |
SMA | OUT2 | Module channel 2 output voltage signal |
Before starting to install the equipment, please be sure to read the "User Manual" carefully and follow the operating procedures specified in the "User Manual" to carry out installation and commissioning
The test platform is shown in the figure below. Due to the high output optical power of the Sensor port (about 500mW), make sure that the Sensor port is connected to a sensing fiber or flange for attenuation before powering on the test platform, and do not look directly at the port with your eyes.
The whole module is connected to the sensing system, and the EDFA power, Raman amplifier power, and VOA value are adjusted through the serial port.
Control software for DAS modules