What Is an Optical Amplifier?

Optical amplifier is a subsystem product that can amplify optical signals in optical fiber communication systems. The principle of the optical amplifier is basically based on the stimulated radiation of the laser, and the amplification effect is achieved by converting the energy of the pump light into the energy of the signal light. Since the commercialization of optical amplifiers in the 1990s, the status quo of the optical fiber communication industry has been profoundly changed.

Chinese name: Optical amplifier
Belong to: Optical fiber communication system

Nature: Subsystem products
based on: Laser stimulated radiation

Introduction to Optical Amplifier

Optical amplifier is to amplify optical signals. Prior to this, the amplification of transmission signals was to achieve photoelectric conversion and electro-optical conversion, that is, O / E / O conversion. With the optical amplifier, the optical signal can be directly amplified. The development and industrialization of optical amplifiers is a very important achievement in optical fiber communication technology, which has greatly promoted the development of optical multiplexing technology, optical soliton communication and all-optical networks. ^[1]

Optical amplifier type

There are two main types of optical amplifiers, semiconductor amplifiers and fiber amplifiers. Semiconductor amplifiers are divided into resonant and traveling wave types; fiber amplifiers are divided into rare-earth-doped fiber amplifiers and nonlinear optical amplifiers. Non-linear optical amplifiers are divided into Raman (SRA) and Brillouin (SBA) fiber amplifiers.

Optical amplifier fiber amplifier

It is doped with rare earth ions (such as europium, europium, europium, etc.) in the optical fiber as a laser active material. The gain bandwidth of each dopant is different. The gain band of erbium-doped fiber amplifiers is wide, covering the S, C, and L bands; the gain band of erbium-doped fiber amplifiers is the S-band; the gain of erbium-doped fiber amplifiers

Optical amplifier The band is around 1310nm.

Raman optical amplifier

It is an optical amplifier made by using the Raman scattering effect, that is, after a high-power laser is injected into an optical fiber, a nonlinear effect Raman scattering occurs. In the process of continuous scattering, the energy is transferred to the signal light, so that the signal light is amplified. It is not difficult to understand that Raman amplification is a

Optical amplifier Distributed amplification process, that is, gradually enlarge along the entire line. Its working bandwidth can be said to be very wide and almost unlimited. This optical amplifier has begun commercialization, but it is quite expensive.

Optical amplifier semiconductor optical amplifier

Generally refers to a traveling wave optical amplifier, which works similarly to a semiconductor laser. Its working bandwidth is very wide. However, the gain is slightly smaller, making it more difficult to manufacture. Although this kind of optical amplifier has been put into practical use, the yield is very small.

In a WDM optical transmission system using an optical amplifier in its transmission path, a monitoring signal channel for monitoring and controlling the operation of the amplifier and spectrally separating it from data transmission can be multiplexed with data. A structure of an amplifier is disclosed, which can be upgraded as the transmission system upgrades to increase the data processing capacity, such as increasing data transmission in the band and / or in the opposite direction, but it is not necessary to interrupt the data transmission through the amplifier to be upgraded path. This structure is implemented using channel dropout and insertion filters. The configuration of these filters is such that the amplified data is transmitted.

Optical amplifier The output path is extended and the drop / inserted channels are passed through these filters.

Application Date: June 06, 2000

Release Date: April 25, 2001

Authorization announcement date: December 31, 2003

Applicant / Patentee: Nottel Networks

Applicant Address: Quebec, Canada

Inventor and designer: Kevin P. Jones; Roger M. Gibb; Robert A. Baker; Martin P. Pietec; Mark E. Bree; Barry Bringt; Toby J. Red; Allen A. Soheim; Robert W. Keith; Mark R. Heinz; Joseph Mun; Nigel E. Jolly; Alan Rubin Johnson; Jonathan P. King; Simon P. Parry

Patent Agency: China International Trade Promotion Commission Patent and Trademark Office

Agent: Jiang Shixun

Patent Type: Invention Patent

Classification: G02F1 / 39

Optical amplifier principle

The composition of Erbium-doped Optical Fiber Amplifier (EDFA) basically includes erbium-doped fiber, pump laser, and optical combiner. Based on different uses, erbium-doped fiber amplifiers have developed a variety of different structures.

The amplification principle of EDFA is similar to the principle of laser generation. The energy difference between the meta-stable state and the ground state of the rare earth element Er (3+) in the fiber is equivalent to the energy of 1550nm photons,

When the pump light energy (980nm or 1480nm) of the appropriate wavelength is absorbed, the electrons will transition from the ground state to an excited state with a higher energy level, and then release a small amount of energy to transfer to a more stable metastable state. When the light source is sufficient, the electrons of the hafnium ions will undergo population reverse, that is, the metastable state at a high energy level will have more electrons than the ground state electrons with a lower energy level. When an appropriate optical signal passes, the metastable electrons will be affected. Stimulation radiation effect, which emits a large number of photons of the same wavelength, but because of the existence of vibrational energy levels, the wavelength is not a single but a range. Typical values are 1530 ~ 1570nm,

Optical amplifier history

The earliest research on erbium-doped fiber amplifier was University of Southampton, UK. ^[1]

The development direction of optical amplifier fiber amplifier

Due to the development of ultra-high-speed, large-capacity, and long-distance fiber-optic communication systems, new requirements have been placed on fiber amplifiers as key components in the field of fiber-optic communication in terms of power, bandwidth, and flatness. In China, the development direction of fiber amplifiers mainly includes the following aspects:

(1) Development of EDFA from C-Band to L-Band;

(2) Wide-spectrum, high-power fiber Raman amplifier;

(3) Use a partially flat EDFA with a fiber Raman amplifier in series to obtain a flat gain amplifier with ultra-wideband;

(4) Development of strain-compensated, non-polarized, monolithically integrated, optically connected semiconductor optical amplifier optical switches;

(5) Develop fiber amplifiers with dynamic gain flattening technology;

(6) Miniaturized and integrated fiber amplifier.

With the continuous breakthrough of new materials and new technologies, it will not be a dream to obtain 300nm ultra-wideband with a bandwidth of 1292 ~ 1660nm in the fiber amplifier. Tbit / s DWDM optical network transmission system will definitely be realized. ^[1]