Optical Amplifiers are devices that amplify the optical light directly without conversion into electrical signals. There are many types of Optical amplifier, but I am going to introduce to you the Semiconductor Optical Amplifier (SOA).

1. By:. Eng. Paulo Vangui
OPTICAL AMPLIFIER
SEMICONDUCTOR OPTICAL AMPLIFIER

2. INTRODUCTION
WITH THE RAPID DEVELOPMENT OF THE OPTIC COMMUNICATION NETWORK, LONGER
TRANSMISSION LENGTHS ARE REQUIRED. OPTICAL AMPLIFIER CAN SATISFY THE
REQUIREMENTS OF OPTICAL COMMUNICATION NETWORKS AT LONGER DISTANCE.
OPTICAL AMPLIFIER
AN OPTICAL FIBRE AMPLIFIER IS A FIBRE OPTIC DEVICE USED TO AMPLIFY OPTICAL
SIGNALS DIRECTLY WITHOUT CONVERSION INTO ELECTRICAL SIGNALS.
AMPLIFIERS ARE INSERTED AT SPECIFIC PLACES TO BOOST OPTICAL SIGNALS IN A
SYSTEM WHERE THE SIGNALS ARE WEAK. THIS BOOST ALLOWS THE SIGNALS TO BE
SUCCESSFULLY TRANSMITTED THROUGH THE REMAINING CABLE LENGTH. IN LARGE
NETWORKS, A LONG SERIES OF OPTICAL FIBRE AMPLIFIERS ARE PLACED IN A
SEQUENCE ALONG THE ENTIRE NETWORK LINK.
THERE ARE MANY TYPES OF OPTICAL AMPLIFIER.
IN THIS PRESENTATION WE ARE GOING TO DISCUSS ABOUT:
SEMICONDUCTOR OPTICAL AMPLIFIER (SOA).

3. THE BASICS OF SEMICONDUCTOR
OPTICAL AMPLIFIER (SOA)
Semiconductor optical amplifiers: Use semiconductors to produce the
gain medium in the laser.
SOA optical amplifiers use the semiconductor as the gain medium, which
are designed to be used in general applications to increase optical launch
power to compensate for loss of other optical devices. Semiconductor
optical amplifiers operate at signal wavelengths between 0.85 µm and
1.6 µm and generating gains of up to 30 dB. Semiconductor optical
amplifier, available in 1310nm, 1400nm, 1500nm, 1600nm wavelength,
can be used with singlemode.

4. WORKING PRINCIPLE OF SOA
AMPLIFIER
SOAs amplify incident light through stimulated emission.
Stimulated emission
If the electron is in the excited state E2 and a photon is incident on it, then the
incident photon interacts with the electron in the excited state and then it
stimulates or induces the electron to come down to the ground state E1. A fresh
photon is emitted in this process.

5. Those stimulated photons have the same wavelength as the optical signal, thus
amplifying the optical signal.

6. Types of soa
There are two types of SOAs:
• Fabry- Perot amplifiers (FPA) Lots of reflection so higher probability of
spontaneous emission (more noise).
• Traveling-wave amplifiers (TWA) Single path through the amplifier. Less
spontaneous emission (Less noise).

7. Advantages:
• Small size.
• Less expensive than EDFA, etc.
Limitations (Disadvantages):
• Lower gain (20-30 dB) than EDFA
• Higher noise(7-12 dB) than EDFA, etc.

8. CONCLUSION
Based on our research we conclude that:
Optical Amplifiers are devices that amplify the optical light directly without
conversion into electrical signals.
Optical amplifier can satisfy the requirements of optical communication
networks at longer distances.
There are many types of Optical amplifier.
And we discussed about the Semiconductor Optical Amplifier, which amplify the
incident light through stimulated emission.
There are two types of SOAs:
• Fabry- Perot amplifiers (FPA) Lots of reflection so higher probability of
spontaneous emission (more noise).
• Traveling-wave amplifiers (TWA) Single path through the amplifier. Less
spontaneous emission (Less noise).

9. REFERENCES
Slidesharenet. (2018). Slidesharenet. Retrieved 16 April, 2018, from
https://www.slideshare.net/SaimunurRahman/comparison-among-fiber-
amplifiers
Fiber-optic-solutionscom. (2017). Fiber Optic Solutions. Retrieved 16
April, 2018, from http://www.fiber-optic-solutions.com/introduction-
semiconductor-optical-amplifier-soa.html