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Optical multiplexers and amplifiers
Published in Matthew N. O. Sadiku, Optical and Wireless Communications, 2018
An optical amplifier is a device that amplifies the optical signal directly without photon-to-electron conversion; it amplifies the light itself. The ideal amplifier would have the following properties:5Provide high gain and uniform gain over its spectral widthHave broad bandwidthAllow bidirectional operationHave low insertion when inserted into a fiber linkHave good conversion efficiency
Laser Transmitters: Coherent and Direct Detections
Published in Hamid Hemmati, Near-Earth Laser Communications, 2018
Rare-earth-doped fiber lasers and amplifiers are a key subsystem in today’s telecommunication systems. They are well suited for free-space laser communications links [14]. Depending on the desired characteristics, a large number of different rare-earth ion dopants (Nd, Yb, Er, Pr, etc.) are available. The host fiber is glass based (SiO3–GeO2), with other glass forming oxides (Al2O3). Popular fiber optical amplifiers include ytterbium-doped fiber amplifiers (YDFA) or EDFA, semiconductor optical amplifiers (SOA), and Raman fiber amplifiers. In an EDFA, erbium ions (Er3+) are added to the fiber core material as a dopant (impurity). Typical dopant levels are a few hundred parts per million. The fiber remains highly transparent to the Er emission (amplification) wavelength, even when light from the pump laser diodes excites it. The resulting gain medium in the fiber functions as an amplifier. Popular pump laser wavelengths for EDFAs are 980 and 1480 nm. As Figure 4.26 illustrates, multiple stages of amplification are commonly utilized for boosting the output power to the desired levels.
Optical Amplifiers
Published in Abdul Al-Azzawi, Photonics, 2017
The development of the optical amplifier (OA) in the late 1980s revolutionized communication systems. Optical amplifiers had an important impact similar to the invention of the laser in early 1960s. Both devices contributed to the development of communication systems and other applications, such as lower pump optical power, single pixel multicolour displays, and light emitting devices. An optical amplifier is a device that amplifies the optical signal directly, without converting it to an electrical signal and then to an optical signal again. OAs are used for amplifying a weak optical signal in order to increase the distance the signal can be transmitted down the transmission lines. In comparison, repeaters and generators convert the signal to electrical form, regenerate or amplify the signal, and then convert it to optical form again. The conversion of the signal from one form to another is a complex process, subject to high losses, slow speed, and more costly than simpler optical amplifiers.
Bidirectional coherent optical communication system combining unidirectional optical signal amplification
Published in Journal of Modern Optics, 2020
Shiwen Jin, Shuqiang Chen, Miao Yan, Yuanyuan Jiang
The usage of optical amplifiers is essential due to power losses in couplers and optical fibers. If the distributed Raman amplifier is employed, not only the modulated and carrier wave will be amplified, the RB of the carrier and the DRB of the modulated wave will also be amplified. We have investigated two types of DRA on the basis of the DCF, as shown in Figure 3. Two optical circulators are used to separate the carrier and the modulated signal. The white and black arrows indicate the flow of the carrier and modulated signal, respectively. The configurations avoid the amplification of the RB of the carrier while amplify the modulated signal. Compared with Figure 3(a), A Fiber Bragg grating is added to the DRA shown in Figure 3(b) that enables reflection of pump light and transmission of modulated signal. After the pump light and the modulated signal are coupled into the DCF, the modulated signal is amplified, then the pump light is reflected back to the DCF by the Fiber Bragg grating so as to re-amplify the modulated signal.
Highly ultra-broadband QD-SOA exploiting superimposition of quantum dots
Published in Journal of Modern Optics, 2022
Samiye Matloub, Arezou Eftekhari, Ali Rostami
There has been a tremendous growing demand for ultra-high broadband amplification devices due to numerous applications in optical communication networks based on dense wavelength division multiplexing (DWDM) technology, high-speed computing systems, online medical services, and online learning systems [1–10]. Hence, various optical amplifiers including the doped fibre amplifiers [11], fibre Raman amplifiers [12,13], parametric amplifiers [14–16], and semiconductor optical amplifiers (SOA) [17–25] have been developed to fulfil the wide range of optical spectra with the simplest and cost-effectiveness methods.
Computer Model for EDFA Dynamics Over 1525–1560 nm Band Using a Novel Multi-Wavelength MATLAB Simulink Test Bed for 8-Channels
Published in IETE Journal of Research, 2018
Reena Sharma, Sanjeev Kumar Raghuwanshi
One of the most important optical amplifier is the erbium- doped fibre amplifier (EDFA). Wavelength-division multiplexing (WDM) technology employing erbium-doped fibre amplifiers (EDFAs) provides a platform for significant improvement in network bandwidth capacity and WDM will play a dominant role in backbone infrastructure supporting the next-generation high-speed networks. The EDFA was first reported in 1987 and the progress in this technology has been so rapid that American Telephone and Telegraph has already put into different services since 1993 [2].