At this time, a high-speed and precise optical signal adjustment solution came into being - the electrical fiber delay line. It uses electric control to achieve precise adjustment of the transmission time of optical signals. It has significant advantages such as high speed, low loss, and continuous adjustment. It is widely used in radar, communication, medical imaging, optical measurement and other fields.
This article will combine the picture content to deeply analyze the core structure, working principle, performance characteristics and application advantages of the electrical fiber delay line, and reveal how it can achieve high-speed and precise optical signal adjustment.
1. What is an electrical fiber delay line?
The electrical fiber delay line is a device for accurately adjusting the transmission time of optical signals. It changes the propagation path length of the optical signal in the optical fiber through electric control, thereby achieving precise control of the delay time of the optical signal.
Compared with traditional manual fiber delay lines, electric fiber delay lines have the advantages of fast adjustment speed, high precision, and remote control, and are particularly suitable for systems that require fast response or automated control.
2. The core structure of electric fiber delay lines
According to the picture content, electric fiber delay lines are mainly composed of the following parts:
- Fiber transmission path
Optical fiber is the core medium of the delay line. When the optical signal propagates in the optical fiber, its propagation time is determined by the following formula:
t= cn⋅L/c
Where t is the delay time, n is the refractive index of the optical fiber, L is the optical fiber length, and c is the speed of light.
By changing the optical fiber length L, the delay time can be precisely controlled.
- Electric adjustment mechanism
The electric fiber delay line uses an electric drive mechanism (such as a stepper motor or servo motor) to automatically adjust the optical fiber path length through a precision slide or rotation mechanism to achieve fast and precise delay control.
- Control interface and drive circuit
Electric delay lines are usually equipped with standard control interfaces (such as RS-232, USB or Ethernet), which can be connected to computers or control systems for remote control and automated operation.
- Optical interface and coupling system
In order to ensure efficient transmission of optical signals, high-precision fiber connectors (such as FC/APC) are usually installed at both ends of the delay line, and optical coupling structures with low insertion loss are used to minimize signal attenuation.
3. Working principle of electric fiber delay line
The working process of electric fiber delay line can be divided into the following steps:
- Optical signal input
The optical signal enters the delay line system through the optical fiber connector and couples into the delayed optical fiber path.
- Electric adjustment of path length
According to system requirements, the electric drive mechanism automatically adjusts the physical length of the optical fiber. For example, increasing the length of the optical fiber by 1 meter can introduce a delay of about 5 nanoseconds (depending on the refractive index of the optical fiber).
- Optical signal output
The delayed optical signal is transmitted to the downstream system through the output optical fiber connector to achieve time synchronization or signal processing.
4. Performance characteristics: high speed, precision, stability
The electric fiber delay line has the following significant performance characteristics:
- High-speed adjustment
The electric drive mechanism can achieve millisecond or even faster delay adjustment, which is suitable for dynamic systems and real-time control.
- High precision
Using precision motors and feedback control systems, the delay adjustment accuracy can reach picoseconds, meeting the needs of high-precision synchronization.
- Low insertion loss
High-quality optical fiber and efficient coupling structure ensure that the insertion loss is less than 1dB, and the signal strength is retained to the maximum extent.
- Wide adjustment range
The electric delay line can achieve delay adjustment from nanoseconds to microseconds, which is suitable for a variety of application scenarios.
- Remote control and automation
Supports a variety of control interfaces and can be integrated into the automation system to achieve remote control and programming operations.
5. Application field: "behind-the-scenes hero" of precise time control
Electric fiber delay lines are widely used in the following fields:
- Radar system
In phased array radars, the signals between different antenna units must be precisely synchronized. Electric fiber delay lines are used to adjust the transmission time of each signal to ensure accurate beam pointing.
- Medical imaging
In medical imaging systems such as OCT (optical coherence tomography), electric delay lines are used to adjust the optical path difference between the reference optical path and the signal optical path to achieve high-resolution imaging.
- Optical communication
In high-speed optical communication systems, electric delay lines are used to synchronize signals of different channels to avoid data misalignment and improve transmission reliability.
- Optical measurement and sensing
In systems such as interferometers and fiber optic sensors, electric delay lines are used to adjust the optical path to achieve high-precision measurement and sensing.
6. Future development trends: intelligence and integration
With the continuous advancement of science and technology, electric fiber delay lines are also evolving:
Higher precision: using nanometer-level adjustment mechanisms to achieve sub-picosecond delay control;
Lower loss: using low-loss optical fibers and efficient coupling technology to improve signal quality;
Intelligent control: combined with a closed-loop feedback system to achieve automatic calibration and real-time adjustment;
Integrated design: integrating delay lines with optical switches and modulators to build multifunctional photonic modules.
7. Conclusion: Mastering time, mastering light
Although inconspicuous, the electric fiber delay line plays the role of "time guardian" in countless high-precision systems. It provides solid technical support for radar, communication, medical treatment, measurement and other fields by precisely controlling the transmission time of optical signals.