C-band erbium-doped fiber small signal amplifier

Working principle

Erbium doped fiber is the core component of PA amplifiers, which amplifies optical signals by doping the rare earth element erbium (Er) into the fiber core. Erbium ions have a special energy level structure, and when excited by pump light, they transition from low energy levels to high energy levels. When the signal light passes through an erbium-doped fiber, high-energy erbium ions are stimulated to emit photons with the same phase, frequency, and polarization state as the signal light, thereby enhancing the intensity of the signal light and achieving amplification.

Pump light is a light source that provides energy for erbium ions, typically using semiconductor lasers (such as 980nm or 1480nm wavelength lasers). After the pump light enters the erbium-doped fiber, it interacts with erbium ions, causing them to transition to high energy levels. These high-energy erbium ions generate photons identical to the signal light through stimulated emission, achieving amplification of the signal light. This pumping mechanism enables PA amplifiers to emit large optical signals without directly converting the signal light into electrical signals.

In order to ensure the quality of the amplified signal, PA amplifiers reduce noise by optimizing the structure of erbium-doped fibers, selecting appropriate pump light wavelengths and powers, and other measures. The noise figure is controlled at ≤ 4.5dB to ensure that the amplifier maintains a good signal-to-noise ratio while amplifying the signal, thereby improving signal quality.

Application scenarios

In fiber optic communication systems, C-band erbium-doped fiber small signal amplifiers are used to compensate for the loss of optical signals in fiber optic links, improving the transmission distance and capacity of the communication system. For example, in submarine fiber optic cable communication systems, this amplifier can effectively restore the attenuated optical signal strength, ensuring the quality and reliability of communication.

In fiber optic sensor networks, this amplifier can amplify the weak optical signal output by the sensor, improving the measurement accuracy of the sensor. For example, in fiber optic temperature sensors, it can amplify the intensity changes of optical signals caused by temperature changes, ensuring the accuracy of temperature measurement.

In fiber laser systems, C-band erbium-doped fiber small signal amplifiers can be used to increase the power of laser seed sources, thereby obtaining higher power laser outputs, which can be used for applications such as material processing and medical laser treatment.