Introduction to the Fiber Optic Delay Line

Fiber optic delay lines: the elements or devices used to delay electrical signals for a period of time are called fiber optic delay lines.

In recent years, with the rapid development of the electronic industry, these components are widely used in precise oscilloscopes, color TVs, electronic computers, industrial process control, modern radar systems and other fields.

Ⅰ. The characteristics of fiber optic delay lines

Fiber optic delay lines should have flat amplitude-frequency characteristics and certain phase-shift characteristics (or delay-frequency characteristics) in the passband, with appropriate matching impedance and small attenuation. For analog signals, it is generally composed of inductors and capacitors, or directly matched with coaxial cables and spirals. For digital signals, charge-coupled devices or surface acoustic wave devices are used.

Ⅱ. The extensive application of fiber optic delay lines

Fiber optic delay lines are widely used in radar, electronic computers, color TV systems, communication systems, and measuring instruments (such as oscilloscopes).

Fiber optic delay lines are widely used in precise oscilloscopes, color TVs, electronic computers, industrial process control, modern radar systems and other fields. Several common types of fiber optic delay lines are: coaxial cable delay line, ultrasonic delay line, optical waveguide delay line, etc.

Ⅲ. Classification of fiber optic delay lines

Fiber optic delay lines are mainly divided into two categories: electromagnetic delay lines and ultrasonic delay lines. The delay of electromagnetic delay line is from a few nanoseconds to tens of microseconds, and the amplitude-frequency characteristics are mostly low-pass type. When the delay is more than a few microseconds, the bandwidth of 3 dB is below several megahertz. The delay of the ultrasonic delay line is from several microseconds to several thousand microseconds, and the amplitude-frequency characteristic is band-pass type, and the center frequency can reach more than several hundred megahertz.

Ⅳ. Microwave fiber optic delay line

Microwave fiber optic delay lines are used for microwave signal delay simulation. Fiber optic delay lines are the preferred solution for radar verification systems, RF communication systems, microwave signal processing systems and other related applications. The input RF signal is converted to a modulated optical signal, which is then fed into a single-mode fiber with a fixed delay, and then converted back to an RF signal at the output.

1. Advantages of microwave fiber optic delay lines

(1) High bandwidth;

(2) Anti-electromagnetic interference;

(3) Optional different light wavelengths: 1310nm/1490nm/1550nm;

(4) Anti-surge power protection, reliable power supply, and environment adaptability;

(5) Self-adaptive temperature compensation capability, can control the stable output of the light source;

(6) Compact and small size;

(7) Applicable to military standards.

2. Applications of microwave fiber optic delay lines

(1) Radar calibration;

(2) Radio altimeter calibration;

(3) Wireless signal processing;

(4) Electronic countermeasures;

(5) Radar signal delay.