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C-Band Optical Amplifiers (BOAs and SOAs), 1550 nm
Actual Size Compared to
The center wavelength of a BOA can be readily tailored for specific applications. It is quite common to adjust the BOA wavelength spectrum to match the specific laser source. Please contact us if you have custom wavelength requirements for pilot-projects or OEM applications.
BOAs and SOAs are single-pass, traveling-wave amplifiers that perform well with both monochromatic and multi-wavelength signals. Since BOAs only amplify one state of polarization, they are best suited for applications where the input polarization of the light is known. For applications where the input polarization is unknown or fluctuates, a Semiconductor Optical Amplifier (SOA) is required. However, the gain, noise, bandwidth, and saturation power specifications of a BOA are superior to that of a SOA because of the design features that make the SOA polarization insensitive.
Thorlabs offers both free space and fiber-coupled versions of its BOAs and SOAs. Free space versions are offered either as a chip on submount (C) or chip on heatsink (H). Fiber-coupled optical amplifiers are offered and exhibit low coupling losses. Losses typically range from 1.5 to 2.5 dB for the fiber-to-chip and chip-to-fiber coupling (each). This affects the total gain, noise figure (NF), and saturation power (Psat). While the gain produced by the amplifier exceeds that of the losses, these losses remain an important factor in determining the device's performance. For instance a 1 dB drop in input coupling efficiency increases the noise figure by 1 dB. Alternatively, a 1 dB drop in output coupling decreases the saturation power by 1 dB.
Center Wavelength Note
Booster Optical Amplifiers
The BOA consists of a highly efficient InP/InGaAsP Multiple Quantum Well (MQW) layer structure. As seen in the schematic to the right, the input and output of the amplifier is coupled to the reliable ridge waveguide on the optical amplifier chip. C-Band BOAs are available in a standard 14-pin butterfly package with either SMF or PMF pigtails that are terminated with FC/APC connectors. The connector key is aligned to the slow axis on all PMF pigtailed models. Optional polarization-maintaining isolators at the input, output, or both input/output are also available (specifications may vary with different configurations). Please contact Tech Support to order such a device. Alternatively, an unpackaged C-Band BOA chip is available on a submount or heatsink.
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Our SOA1117S and BOA1004P optical amplifiers are also available in the S7FC1013S and S9FC1004P benchtop optical amplifiers, respectively.
Semiconductor Optical Amplifiers
The Semiconductor Optical Amplifier (SOA) is a polarization insensitive optical amplifier; therefore, all polarization states are amplified. These devices are an ideal in-line amplifier. Advanced epitaxial wafer growth and opto-electronic packaging techniques enable a high output saturation power, low noise figure, and large gain across a broad spectral bandwidth. These devices come in an industry-standard 14-pin butterfly package with either SMF or PMF pigtails that are terminated with FC/APC connectors. The connector key is aligned to the slow axis on all PMF pigtailed models. These come without isolators, but we are able to provide units with polarization-insensitive isolators at the input, output, or both. Please contact Tech Support for help in ordering such a device.
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Figure 1: Diagram of the BOA1007C (top down view). The anode and cathode sections of the chip are highlighted here. Please note that the BOA1007H has the same chip structure, and thus, its anode and cathode sections can be similarly determined.
Note: All plots illustrate typical performance, and individual units may have slightly different performance, within the parameters outlined on the Specs tab.
Semiconductor Optical Amplifiers (SOAs and BOAs) are similar in design to Fabry-Perot Laser Diodes. The difference being that Fabry-Perot laser diodes have reflective coatings on both end faces of the semiconductor chip. The optical feedback from the end faces establishes a cavity in which lasing can occur. SOAs and BOAs have an anti-reflection (AR) coating on both end faces of the semiconductor chip. The AR coatings limit the optical feedback into the chip so that lasing does not occur.
As is typical for all amplifiers, SOA/BOAs operate in two regimes: a linear, flat, constant gain regime and a non-linear, saturated output regime. When used to amplify a modulated signal, the linear regime is typically used to eliminate pattern-dependent distortion, multi-channel cross-talk and transient response issues common to EDFAs. The non-linear regime is used to take advantage of the highly non-linear attributes of the semiconductor gain medium (cross-gain modulation, cross phase modulation) to perform wavelength conversion, optical 3R regeneration, header recognition, and other high-speed optical signal processing functions.
For a CW input signal, the maximum amount of power that can be produced by the amplifier while remaining in the linear regime is given by Ppeak. The amount of power produced by the amplifier is determined by the saturation output power, Psat. Note that in the graph below, Ppeak is the maximum output power in the linear regime, and Psat is the saturation output power in the non-linear regime. Psat is defined as the output power at which the small-signal gain has been compressed by 3 dB. The maximum amount of CW power that can be extracted is approximately 3 dB higher than the saturation power.