Fiber Optic Delay Line: High-Precision Control

About Fiber Optic Delay Line

A fiber optic delay line is a device or component that introduces time delay by using the transmission characteristics of optical fibers. It is widely used in various fields such as communications, radar, medical imaging diagnostics, and optical measurements.

Working Principle of Fiber Optic Delay Line

The working principle of a fiber optic delay line is primarily based on the slower transmission speed of light in the optical fiber, as well as the phenomena of light interference and diffraction. When a radio frequency (RF) electrical signal is input into a laser diode (LD), the LD converts it into a modulated optical signal, which is transmitted through the optical fiber. Due to the slower transmission speed of light in the fiber (about two-thirds the speed of light), precise time delay can be introduced by controlling the length of the fiber. Eventually, a photodetector (PD) converts the RF modulated optical signal back into the original RF electrical signal.

What Are the Characteristics of a Fiber Optic Delay Line?

Unique Delay Mechanism

Fiber optic delay lines can operate continuously and reliably.

Wide Delay Range

The delay range of fiber optic delay lines is extensive and can be customized according to user requirements.

High Precision

The delay precision can reach the picosecond (ps) level.

High Stability

Optical fibers are not affected by external electromagnetic interference, providing reliable and consistent time delay performance.

Low Loss

Fiber optic delay lines have low polarization-related loss and insertion variation.

Broadband Characteristics

They have a broad frequency response to optical signals, supporting broadband signal transmission.

Classification of MEISU's Fiber Optic Delay Lines

Fiber optic delay lines are mainly classified into electromagnetic delay lines and ultrasonic delay lines. The delay time of electromagnetic delay lines ranges from a few nanoseconds to several tens of microseconds, with a low-pass amplitude-frequency characteristic. When the delay time exceeds a few microseconds, the 3dB bandwidth is below a few megahertz. Ultrasonic delay lines have a delay time ranging from a few microseconds to several thousand microseconds, with a band-pass amplitude-frequency characteristic and a center frequency that can reach several hundred megahertz.