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Controlled optical signal conditioning for automated optical workflows
Keysight optical attenuators provide precise control of optical signal power for accurate and repeatable optical component testing. Attenuators emulate signal loss, balance power levels, and protect sensitive devices during testing. Keysight attenuators offer low insertion loss, low polarization-dependent loss (PDL), and high resolution across a wide attenuation range. These features ensure accurate and stable signal control in both single-mode and multimode applications. Select the optical attenuator you need to simulate real-world optical link conditions, calibrate power levels, or automate signal conditioning in your optical test setup based on maximum attenuation and number of channels. Choose one of our popular configurations or configure one specific to your application.
Wide attenuation range
Offers fine control across a broad range up to 60 dB, enabling accurate signal loss emulation for diverse optical power levels and test scenarios.
Fast switching speed
Rapid attenuation adjustment improves test throughput and responsiveness for automated applications with quick signal level changes.
High repeatability
Delivers highly repeatable attenuation settings over thousands of cycles, supporting stable, automated test setups and long-term use in manufacturing environments.
Ultra-low PDL
Minimizes polarization-dependent loss to ensure consistent and accurate attenuation across varying signal polarizations, ideal for precision testing of sensitive optical components.
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Maximum attenuation
35 dB to 60 dB
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Number of channels
1 to 4
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Insertion loss
< 1.7 dB to <2.2 dB
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Power range
+20 dB to -50 dB, +20 dB to -35 dB
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Fiber mode
Single-mode, Multimode
Most popular configurations
2-Channel Optical Attenuator and Power Meter
4-Channel Optical Attenuator
Four-Channel Multimode Optical Attenuator
- Explore Our Photonic and Optical Test Catalog
- Guide to the Optical Attenuator Family
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Frequently asked questions
An optical attenuator is a device used to reduce the power of an optical signal in a controlled, repeatable way. In test setups, it's essential for emulating signal loss, balancing power levels across channels or paths, and protecting sensitive receivers or components. By mimicking real-world link conditions, optical attenuators help ensure components perform reliably in actual deployments.
Use an optical attenuator whenever you need to:
- Simulate fiber loss in optical links.
- Calibrate and equalize signal levels between devices.
- Prevent overload damage to optical receivers.
- Perform BER or margin testing under degraded conditions.
- Enable automation where dynamic power control is required.
Attenuators are widely used in R&D labs, system validation, and production environments for both passive and active optical components.
When selecting an optical attenuator for your test setup, consider the following key specifications to ensure it meets your application requirements:
- Attenuation Range: Determines how much optical power the attenuator can reduce, typically up to 60 dB. A wide range gives you flexibility to emulate a variety of signal loss conditions.
- Power Range: Refers to the input power levels the attenuator can safely handle. Choose an attenuator that accommodates your maximum signal levels without distortion or damage.
- Insertion Loss: The amount of optical loss introduced when the attenuator is set to minimum or zero attenuation. Low insertion loss ensures minimal signal degradation when attenuation is not needed.
- Wavelength Range: Ensure the attenuator operates accurately over the wavelengths used in your system (e.g., 1260–1650 nm for telecom applications). Performance may vary with wavelength, so this is critical for broadband or wavelength-selective testing.
- Fiber Mode Compatibility: Select an attenuator that matches your fiber type—single-mode for long-haul and high-precision applications, or multi-mode for short-reach and industrial systems. Mode mismatch can lead to measurement errors.
Additional important specs may include polarization-dependent loss (PDL) for sensitive testing, repeatability for automation, and switching speed for dynamic test scenarios. Matching these parameters to your testing environment helps ensure reliable, accurate results.
Polarization-Dependent Loss (PDL) refers to variations in attenuation based on the polarization state of the signal. In precision testing, especially for coherent or polarization-sensitive components, low PDL ensures consistent results regardless of signal polarization. This is especially important when characterizing modulators, transceivers, and photonic integrated circuits.