SOA (Semiconductor Optical Amplifiers)
An SOA (Semiconductor Optical Amplifier) is a semiconductor element that amplifies light. Antireflective processing is applied on both facets of a semiconductor laser to eliminate the resonator structure. When light enters from outside the semiconductor, the light is amplified by stimulated emission.
SOA is used for amplifying an optical signal. SOAs are included in the optical transceiver modules used for communication between data centers to amplify the optical signal in the 1.3 um band used for Ethernet communication in order to compensate for transmission loss.
Anritsu provides SOA modules that have high optical gain of 15 dB or higher and a low noise figure of 7 dB or less. The polarization dependent gain is also 1.5 dB or less, which enables signal amplification with practically no problem. The module is a 6-pin compact package with an isolator and TEC (Thermo-Electric Cooler), and can be mounted on CFP/CFP2.
It also complies with Telcordia GR-468-CORE for extremely high reliability, as well as the RoHS directive.
Amplification Wavelength Characteristics
Amplification Current Characteristics
- Optical gain: 15 dB or more (pin = -25 dBm, 120 mA)
- Polarization dependent gain: 1.5 dB or less
- Wavelength range: 1,294 to 1,311 nm
- Saturation power: 7 dBm (typical)
- Noise figure: 7 dB (typical)
- 6-pin compact package
Recent years have seen a dramatic increase in communication within and between data centers, and Ethernet standardized with IEEE802.3ba is used for this communication. 100GBASE-LR4/ER4 uses 4 wavelengths in the 1.3 μm band with little wavelength dispersion (λ0: 1,294.53 to 1,296.59 nm, λ1: 1,299.02 to 1,301.09 nm, λ2: 1,303.54 to 1,305.63 nm, and λ3: 1,308.09 to 1,310.19 nm) to perform wavelength multiplexing on laser light for transmission with one single mode optical fiber. Since the transmission distance of LR4 is 10 km, an amplifier is not required for the receiver. On the other hand, since ER4 has a transmission distance of 40 km for long-distance communication, an SOA is included in the optical receiver to compensate for transmission loss.
Schematic of Communication between Data Centers
Schematic of Compensating Transmission Loss in 100GBASE-ER4 Communication
Various Optical Amplifiers (EDFA, FRA, and SOA) >