Booster Optical Amplifiers (BOAs), 1685 nm

  • Polarization-Dependent Booster Optical Amplifiers (BOAs)
  • SM or PM Fiber-Pigtailed Butterfly Package
  • 1685 nm ASE Center Wavelength

FC/APC Connectors


BOA with PM Fiber and FC/APC Connectors; Close-up of Butterfly Package Shown


BOA with SM Fiber and
FC/APC Connectors

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  • Amplifying Polarized Laser Signals Around 1685 nm
  • Amplifying Widely Tunable Lasers Around 1685 nm
  • Preamplifier for Telecom Applications Beyond U-Band
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.
Internal Diagram
Click to Enlarge
When current is applied across the ridge waveguide, excited state electrons are stimulated by input light, leading to photon replication and signal gain.


  • Polarization Dependent: Amplifies One Polarization State
  • 1.5 m Long, SM or PM Fiber Pigtails with FC/APC Connectors
  • Small Signal Gain: 20 dB (Typical)
  • Saturation Output Power: 17 dBm (Typical)
  • 3 dB Bandwidth: 110 nm (Typical)
  • Each End Face of the Semiconductor is AR Coated (R < 0.1%) to Prevent Lasing

Booster Optical Amplifiers (BOAs) 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. Each BOA consists of a highly efficient InP Quantum Well (QW) layer structure, which is designed for amplifying polarized optical signals in the 1685 nm band and is also an ideal gain medium for implementing wide-bandwidth tunable lasers.

As seen in the schematic to the right, the input and output of the amplifier are coupled to the active layer of the ridge waveguide on the optical amplifier chip. The device is contained in a standard 14-pin butterfly package, with either single mode or polarization-maintaining fiber pigtails that are terminated with FC/APC connectors. The BOA1084S uses single-mode, non-polarization-maintaining SMF-28e fiber, while the BOA1084P uses polarization-maintaining PM15-U40A fiber with the connector key aligned to the slow axis. An integrated thermoelectric cooler (TEC) and thermistor allow these BOAs to be temperature controlled, thus stabilizing the gain and the spectrum.

For additional details concerning the construction and operating parameters of our BOAs, please see the Optical Amplifiers tab.

Recommended Driver
The CLD1015 butterfly LD/TEC controller is recommended to control these amplifiers. This LD/TEC controller and mount combination offers full control via a touch screen. When operating these optical amplifiers with the CLD1015, the orientation for type 1 pin configurations should be used.

ASE Center Wavelength
The center wavelength (CWL) of the amplified spontaneous emission (ASE) spectrum in broadband semiconductor devices, such as optical amplifiers, may show variation between lots. Please refer to the blue icons (info) below for the CWL tolerances of each particular model. For applications in which a specific ASE center wavelength is a critical concern, please contact Tech Support for information on the CWL of currently available lots.

Item #a Info Center
Operating Current
3 dB
Saturation Output
Power (@ -3 dB)c,d
Small Signal Gain
(@ Pin = -20 dBm)c,d
Noise Figure
Fiber Type
BOA1084S info 1685 nm 700 mA 110 nm 17 dBm 20 dB 10.6 dB SMF-28e
BOA1084P info PM15-U40A
  • All specifications are typical unless otherwise noted.
  • This is the center wavelength of the amplified spontaneous emission (ASE), and is not necessarily the operating wavelength. An operating wavelength of 1679 nm was selected for testing to yield the specified saturation output power.
  • Measured at 1679 nm
  • Measured at the Operating Current
Comparison of a SOA to a standard Fabry-Perot Laser Diode

Booster optical amplifiers (BOAs) and semiconductor optical amplifiers (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.

BOAs and SOAs 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 reflective 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, BOAs/SOAs 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 continuous wave input signal, the amount of power that can be produced by the amplifier is determined by the saturation output power (Psat) parameter. 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.

SOA Linear vs Non-linear Regimes

Posted Comments:
user  (posted 2024-01-04 08:31:01.037)
Hello, Will this amp be damaged by a pulsed laser with a few hundred fs pulse length but average power input to the amp of ~ 100-300 microWatts?
jdelia  (posted 2024-01-04 03:20:28.0)
Thank you for contacting Thorlabs. While we have not tested these with fs pulses, we unfortunately would expect peak powers higher than 300-500 mW to damage these amplifiers, so we would not suggest this product for your beam. I have reached out to you directly to discuss your application further.
GYEONG HUN KIM  (posted 2023-02-08 19:11:37.307)
I am really want to know that your company (previous COVEGA as far as I know) still have produced extended SOA for 1.7micron center wavelength.
ksosnowski  (posted 2023-02-10 02:35:21.0)
Thanks for reaching out to Thorlabs. Currently we do not make any SOAs with CWL in the 1.7um range. Our BOA1084S/P is fairly broadband (110 nm), which would more than cover 1700 nm. I have reached out directly to discuss your application in more detail.
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BOA1084S Support Documentation
BOA1084S1685 nm Booster Optical Amplifier, 17 dBm, Butterfly Package, SM, FC/APC
BOA1084P Support Documentation
BOA1084P1685 nm Booster Optical Amplifier, 17 dBm, Butterfly Package, PM, FC/APC
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