Semiconductor Optical Amplifiers (SOAs)

What is a Semiconductor Optical Amplifier?

Semiconductor Optical Amplifiers (SOAs) are optical amplifiers that utilize a semiconductor gain medium. They function similarly to laser diodes, but the end mirrors are replaced with anti-reflection coatings to prevent feedback. A signal light is sent through a semiconductor single-mode waveguide, significantly overlapping the active (amplifying) region. This region is pumped with an electric current, creating a carrier density in the conduction band and allowing for optical transitions from the conduction band to the valence band, resulting in the amplification of the signal.

Learn More About Semiconductor Optical Amplifiers

The gain in SOAs is produced through current injection, which amplifies the optical intensity of the signal without the need to convert to electrical signals and back to optical. This makes SOAs a key component in many optical communication systems. They can be used in telecom systems as fiber-pigtailed components, operating at signal wavelengths near 1.3 μm or 1.5 μm, and offering a gain of up to ≈ 30 dB.

SOAs have a wide range of applications. They are used in LIDAR (Light Detection & Ranging), which is useful in autonomous vehicles. The FMCW (Frequency Modulation Continuous Wave) LiDAR with high-powered SOA can detect the faintest object at 1310 or 1550nm in all-weather and direct sunlight conditions. They are also used in communication systems, such as 10 to 40kM mobile phone base stations and data centers at the 1310nm wavelength. In addition, they are necessary for amplifying output power for tunable solid-state lasers used in laser radar, remote sensing, and medical applications. High-resolution infrared spectroscopy also uses high-power Gain Chip in an external cavity laser system with narrow linewidth.

The new SemiNex Semiconductor Optical Amplifier (SOA) provides a cost-effective, high-performance solution to amplifying single-mode lasers for high-power applications. SemiNex’s unique epitaxial and waveguide design allows higher gain and saturation output power than its competition. This makes SOAs versatile and multifunctional devices that are key building blocks for optical networks. They emit light using a semiconductor substance, such as gallium arsenide or indium phosphide. Their ability to amplify optical signals makes them a crucial component in many optical communication systems.

Benefits of Semiconductor Optical Amplifiers

1. Optical Signal Amplification: SOAs can amplify the optical intensity of the signal without the need to convert to electrical signals and back to optical. This makes them highly efficient and reduces signal loss.
2. Broad Bandwidth: SOAs can operate over a wide range of wavelengths, making them versatile for different applications.
3. Fast Response Time: SOAs have a fast response time on the order of nanoseconds, which is beneficial for high-speed communication systems.
4. Compact Size: Due to their semiconductor construction, SOAs are compact and can be easily integrated into existing systems.
5. Cost-Effective: SOAs are generally less expensive than other types of optical amplifiers, such as Erbium-Doped Fiber Amplifiers (EDFAs).
6. Polarization Independence: Designs have been developed which provide nearly polarization-independent characteristics, which are often desirable e.g. in optical fiber communications.
7. Nonlinear Signal Processing: The strong gain saturation in SOAs can be exploited for nonlinear signal processing in telecom systems.
8. Versatility in Applications: SOAs are used in a wide range of applications, including LIDAR, communication systems, tunable lasers, and high-resolution infrared spectroscopy.
9. High Gain: SOAs can offer a gain of up to ≈ 30 dB, limited essentially by amplified spontaneous emission (ASE).
10. Current Injection: The gain in SOAs is produced through current injection, which allows for control over the amplification process.

Best-in-Class Semiconductor Optical Amplifiers from SemiNex

SemiNex received the Innovator’s Award from Laser Focus World for its semiconductor optical amplifier (SOA) platform, designed for optimal performance at 1550 nm and 1310 nm wavelength ranges. This SOA structure is based on a proprietary AlInGaAs material system, featuring an advanced waveguide design with multiple quantum wells on an InP substrate, ensuring excellent optical and thermal performances. At a drive current of 1 A, the SOA channel output power exceeds 350 mW at 1550 nm and 450 mW at 1310 nm, setting an industry standard.

SemiNex’s SOA platform offers the flexibility of a single channel or an array of up to 20 channels. A high channel count and customizable pitch empower system designers to integrate the SOA array with a silicon photonic integrated circuit (PIC), minimizing the final system footprint and reducing overall costs. Addressing the escalating demand for optical power in applications such as optical communications and automotive LiDAR, the SemiNex SOA Array platform is shipping in pre-production volumes to key telecom and automotive customers.

SOAs provide a cost-effective solution for signal amplification compared to alternative technologies. In LiDAR systems, where laser pulses are utilized for distance measurement and 3D mapping, SOAs are crucial in amplifying optical signals. This amplification ensures that transmitted signals maintain sufficient power for accurate and long-range measurements.

SOAs enhance the sensitivity of LiDAR receivers by amplifying weak incoming signals, which is particularly vital for detecting low-reflectivity objects or those positioned at a distance.

SOAs, characterized by fast response times, are well-suited for LiDAR applications requiring rapid signal amplification for real-time mapping and obstacle detection. The quick response time contributes to the overall efficiency of LiDAR systems in dynamic driving scenarios.

SemiNex’s distinctive epitaxial and waveguide designs enable higher gain and saturation output power than competing offerings. For tailored solutions to meet specific project requirements, please get in touch with us today!