To send information from one satellite to another, which can be hundreds of kilometers away, these lasers must be amplified to a high enough level to ensure there is enough power once the beam reaches the receiver.
Optical amplifiers have the advantage of being able to amplify a wide range of wavelengths simultaneously. Several other characteristics are also to be considered when thinking about optical amplifiers for satellites:
- Erbium-doped or erbium/ytterbium-doped active optical fibers allow for amplification in the 1.5 µm wavelength bands, a standard for optical communication.
- Optical amplifiers are compact and lightweight, which is significant for space applications where weight is a critical element.
- Optical fiber amplifiers can also reach extremely high powers, enabling the transmission of information even between two very distant satellites.
Optical amplifiers are also known for their high reliability and long lifespan, which are crucial elements in space communications where repairs are almost impossible to make. One could almost say that the optical amplifier is a highly crucial technology for space communications both now and in the years to come.