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Description

The high power PM fiber optical isolator (1064/1030/980 nm polarization-maintaining optical fiber isolator) is one of the most important passive components. The function of a PM optical isolator is to let a light beam pass through in one direction, that is, the forward direction only, like a one-way traffic. At the same time, the PM optical isolator is able to maintain a well-defined state of polarization (SOP) of the light. The high power PM Isolator (polarization maintaining isolator) is used to prevent reflected light that causes undesirable effects such as frequency instability in laser sources and parasitic oscillation in optical amplifiers. 

Notes:

  • The high power pm fiber optical isolator is customizable, and the above specifications are subject to change without notice.
  • For CW high-power optical interconnection, we recommend fusion splice without connectors.
  • For device with connectors, IL is 0.3dB higher, RL is 5.0dB lower, ER is 2.0dB lower.
  • Unless otherwise specified, the slow axis of the fiber is aligned with the key of the PM fiber connector.
  • Slow axis working and fast axis blocked as standard, while operating on both the slow and fast axis available on request.
  • Bare fiber should not support the weight of the connector. So that if any connectors needed, for the pigtail type it’s better to choose the 900μm loose tube jacket instead of the 250μm bare fiber.
  • For product customization or special requirements, please contact Lfiber’s sales department for availability.

High Power PM Fiber Optical Isolator

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Specifications

Type Of The Device: Isolator
Operating Wavelength: 980 nm
Max Power: 10 W
Min Isolation: 25 dB
Min. Extinction Ratio At 23℃: 20
Peak Power: 10kW, 20kW
Fiber Type: PM1550, PM1310, PM980, Others specified
Connector: None, FC/UPC, FC/APC, SC/UPC, SC/APC, LC/UPC, LC/APC, Others
Average Power: 500mW, 1W, 2W, … 5W, 10W, 20W

Got questions about specs? Use the inquiry form to ask.

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Features

  • High-Power Handling up to 20 W CW
    Engineered for demanding industrial and scientific applications, this high power PM isolator supports average optical power up to 20 W and peak power up to 10 kW for nanosecond pulses, minimizing damage risk in high-energy fiber laser systems.
  • Polarization Maintaining (PM) Design
    Utilizes high-quality PM fibers (PM980, PM1310, PM1550, etc.) and precise axis alignment to preserve polarization state, ensuring stable system performance in polarization-sensitive applications such as MOPA fiber lasers and PM fiber amplifiers.
  • High Isolation for Laser Protection
    Delivers typical isolation of 30 dB and minimum 25 dB at 23℃, effectively suppressing back-reflections and feedback. This protects laser sources and upstream components, improving output stability and extending system lifetime.
  • Low Insertion Loss
    Typical insertion loss of only 0.8 dB (max. 1.0 dB at 23℃) allows more of your source power to reach the target. Optimized optical design and coatings help maximize system efficiency in high-power fiber laser chains.
  • Excellent Polarization Extinction Ratio
    Minimum 20 dB extinction ratio at 23℃ ensures efficient rejection of the undesired polarization axis. This is critical for applications requiring stable linear polarization and high contrast, such as interferometry, sensing, and coherent combining.
  • High Return Loss for Low Back-Reflection
    Minimum input/output return loss of 45 dB reduces reflections into the laser cavity, enhancing spectral purity, power stability, and long-term reliability of the optical source.
  • Optimized for 1064 nm, 1030 nm, and 980 nm
    Available at key wavelengths: 1064 nm (Yb fiber lasers), 1030 nm (Yb-based ultrafast/MOPA), and 980 nm (pump diodes and EDFAs). Each version is precisely centered (±5 nm range) for optimal performance at the target wavelength.
  • Configurable Axis Alignment Modes
    Multiple operating configurations are supported:
    - Slow axis working and fast axis blocked
    - Fast axis working and slow axis blocked
    - Both axes working
    This flexibility allows precise matching to system polarization requirements.
  • Robust Mechanical Package
    Compact metal housing of 58 × 28 × 26 mm with maximum tensile load of 5 N on fibers. The rugged design is suitable for integration into industrial laser heads, optical benches, and OEM modules.
  • Stable Performance over Operating Temperature
    Operating temperature range of +10℃ to +50℃ and storage from 0℃ to +60℃ ensure stable isolation, insertion loss, and polarization extinction in typical lab and factory environments.
  • Connector & Pigtail Options
    Available with 250 μm bare fiber or 900 μm loose tube pigtails, and a wide selection of connectors, including FC/UPC, FC/APC, SC/UPC, SC/APC, LC/UPC, LC/APC, or customized options. For maximum power and lowest loss, fusion splicing without connectors is recommended.
  • Designed for CW and Pulsed Fiber Lasers
    Suitable for both continuous-wave and nanosecond pulsed operation. High peak power capacity and robust internal optics make it ideal for pulsed MOPA systems, marking, micromachining, and amplifier chains.
  • High Reliability and Long-Term Stability
    Built with high-quality materials, advanced assembly, and strict quality control to maintain isolation, insertion loss, and polarization extinction over time, even under elevated power and environmental stress.
  • Customizable to Application Needs
    Parameters such as center wavelength, power rating, package size, pigtail length, fiber type, connectors, and axis configuration can be customized. This allows optimization for specific OEM systems, research setups, and specialty fiber laser platforms.
  • Ideal for Advanced Photonics Systems
    Well-suited for fiber lasers, MOPA fiber lasers, PM fiber amplifiers, pump laser protection, precision measurement, and test instruments where high power, stable polarization, and strong isolation are critical.

Applications

  • High‑Power Fiber Lasers at 1064 nm, 1030 nm, and 980 nm
    Ideal as a unidirectional component in industrial, medical, and scientific fiber laser systems operating around 1 µm and 980 nm, preventing destabilizing back‑reflections from downstream optics and workpieces.
  • MOPA Fiber Laser Systems
    Used in Master Oscillator Power Amplifier (MOPA) architectures to protect the seed oscillator and intermediate amplifier stages from back‑propagating ASE and reflections, helping maintain pulse shape, timing, and spectral purity at powers up to 20 W average and kW‑level peak.
  • Polarization‑Maintaining Fiber Amplifiers
    Integrated in PM ytterbium‑doped and other rare‑earth‑doped fiber amplifier chains to enforce forward‑only propagation, protect gain fibers from reflections, and preserve polarization with high extinction ratio.
  • Ultrafast and Picosecond/Nanosecond Laser Systems
    Suitable for pulsed laser systems with ns‑range peak powers up to 10 kW (or specified), ensuring isolation between oscillator, stretcher/compressor, and amplifier stages while maintaining pulse stability.
  • Seed Laser Protection and Isolation
    Installed directly after narrow‑linewidth or single‑frequency PM seed lasers (including 1030/1064 nm CW and pulsed sources) to protect them from back‑reflections coming from isolators, amplifiers, AOMs, EOMs, or free‑space optics.
  • High‑Power Pump‑Laser Isolation at 980 nm
    Deployed with high‑brightness 980 nm pump diodes used for erbium‑doped and ytterbium‑doped amplifiers, preventing back‑reflected light from damaging diodes and stabilizing pump power.
  • Coherent Beam Combining and Beam Steering Systems
    Used in polarization‑sensitive coherent combining setups and active beam steering modules to ensure one‑way light propagation, maintain defined polarization states, and avoid feedback that can disturb phase locking.
  • Precision Micromachining and Materials Processing
    Integrated in high‑power PM laser sources for cutting, drilling, scribing, welding, and surface texturing of metals, ceramics, semiconductors, and polymers, where strong reflections from the workpiece must not couple back into the laser.
  • Laser Marking, Engraving, and Additive Manufacturing
    Applied in 1 µm fiber laser engines for marking and engraving systems (including QR/2D code marking) and metal 3D printing modules to protect the laser from highly reflective metals and dynamically changing load conditions.
  • Medical and Biomedical Laser Platforms
    Used at 1030/1064 nm and 980 nm in therapeutic and surgical systems (e.g., dermatology, photocoagulation, endoscopy, and tissue interaction studies) to isolate the laser source from reflections at fiber couplers, scanners, and tissue interfaces.
  • Nonlinear Frequency Conversion Stages
    Placed before and after nonlinear crystals or waveguides (e.g., for frequency doubling, supercontinuum generation) to protect seed lasers and amplifiers from back‑propagating light and parasitic oscillations while preserving polarization for phase‑matching.
  • Optical Parametric Amplifier and OPO Pump Isolation
    Used in OPA/OPO pump chains at 1030/1064 nm to safeguard pump lasers from reflections originating in nonlinear cavities or tunable output stages, improving long‑term stability and spectral performance.
  • Fiber‑Based Interferometry and Coherent Detection
    Suitable for PM interferometers (Mach‑Zehnder, Michelson) and coherent detection schemes where feedback to the laser must be strictly limited; the PM design ensures stable polarization for high‑visibility interference fringes.
  • Optical Sensing and LIDAR Systems
    Employed in high‑power lidar, range‑finding, and distributed fiber sensing (DTS/DAS) at 1 µm to isolate transmitters from back‑scattered and reflected signal light, increasing system reliability and protecting sensitive sources.
  • Optical Test and Measurement Instruments
    Integrated into high‑power optical test setups and instrumentation—such as power meters, spectrum analyzers, OTDRs, and interferometric measurement benches—to avoid damaging feedback into test lasers and to preserve linear, repeatable measurements.
  • Quantum Optics and Cold‑Atom Experiments
    Used in PM‑fiber‑based quantum optics platforms at 980 nm and 1 µm for trapping, cooling, and manipulation beams, ensuring polarization stability and isolating lasers from reflections off vacuum windows, optics, and atom clouds.

Frequently Asked Questions

What is a high power polarization maintaining (PM) fiber optic isolator and what is it used for?
A high power PM fiber optic isolator is a passive optical device that allows light to pass in one direction while blocking it in the reverse direction, and at the same time preserves the polarization state of the transmitted light. The Lfiber high power PM isolator is optimized for 1064 nm, 1030 nm, or 980 nm operation with up to 20 W average power handling. It is typically used in fiber lasers, MOPA fiber lasers, polarization maintaining fiber amplifiers, and precision test instruments to protect laser sources from back‑reflections that can destabilize or damage them, while maintaining a defined state of polarization for high‑coherence and polarization‑sensitive applications.
What are the key specifications and performance parameters of the Lfiber high power PM isolator?
At 23 °C, the typical peak isolation is 30 dB with a guaranteed minimum isolation of 25 dB over a ±5 nm operating wavelength range around the center wavelength (1064, 1030, or 980 nm). Typical insertion loss is 0.8 dB with a maximum of 1.0 dB. The minimum extinction ratio is 20 dB, and minimum return loss at input and output is 45 dB. Standard average optical power handling is up to 20 W (with lower‑power variants such as 500 mW, 1 W, 2 W, 5 W, 10 W available depending on configuration), and the maximum peak power for nanosecond pulses can be up to 10 kW or specified. The device operates from +10 °C to +50 °C and can be stored from 0 °C to +60 °C. The standard package dimension is 58 × 28 × 26 mm, and the maximum tensile load on the fiber pigtail is 5 N.
How should I choose the correct wavelength, axis alignment, and fiber type for my application?
Choose the center wavelength (1064, 1030, or 980 nm) to match your laser source’s operating wavelength; the device is specified over ±5 nm around that center. For axis alignment, there are three main options: (1) "Slow axis working and fast axis blocked" – only light aligned to the slow axis is transmitted; this is the most common configuration for PM fiber lasers and amplifiers. (2) "Fast axis working and slow axis blocked" – only the fast axis is transmitted; this is used when the system is designed around the fast axis as the principal polarization. (3) "Both axis working" – both slow and fast axes are transmitted, suitable for applications that need to carry both polarization states. Fiber types are typically PM1550, PM1310, or PM980 depending on wavelength and system requirements. Match the PM fiber type to that used in your laser or amplifier to ensure good splicing performance and polarization maintenance.
What is the difference between bare fiber and 900 µm loose tube pigtails, and when should I use connectors?
Bare fiber pigtails (~250 µm coating) are compact and ideal for permanent fusion‑spliced integration in high‑power CW systems because they minimize connector‑related loss and heating. However, bare fiber should not support the mechanical weight of connectors. For configurations requiring connectors (FC/UPC, FC/APC, SC/UPC, SC/APC, LC/UPC, LC/APC, or others), Lfiber recommends using 900 µm loose‑tube pigtails, which provide additional mechanical protection. Note that adding connectors typically increases insertion loss by about 0.3 dB, reduces return loss by about 5 dB, and reduces extinction ratio by about 2 dB compared with a bare‑fiber, connector‑less configuration. For maximum power handling and reliability, fusion splicing without connectors is generally preferred.
How much optical power can the high power PM isolator handle for CW and pulsed operation?
The standard high‑power configurations of this PM isolator can handle up to 20 W average CW optical power, with lower‑power options (e.g., 500 mW, 1 W, 2 W, 5 W, 10 W) depending on the specific ordering code. For pulsed nanosecond applications, the device supports up to 10 kW peak power as a standard value, with higher peak powers available on request. The actual safe operating power also depends on factors such as duty cycle, pulse width, and thermal management of the package. For CW high‑power applications, Lfiber recommends using fusion splicing and avoiding connectors wherever possible to minimize localized heating and long‑term reliability issues. If your system requires power levels beyond the listed ratings, you should consult Lfiber sales for a customized design and power rating.
How does axis alignment and polarization work in this PM fiber optic isolator?
In a PM isolator, the internal optics and the PM fiber are aligned so that one principal axis (slow or fast) is designated for transmission. When specified as "slow axis working and fast axis blocked," the isolator is optimized so that light launched on the slow axis passes with low loss and high isolation, while light on the fast axis is strongly attenuated. The inverse is true for "fast axis working and slow axis blocked." In "both axis working" versions, both axes are transmitted. Unless otherwise specified, Lfiber aligns the slow axis of the PM fiber with the key of the PM fiber connector, which is standard practice in the industry. Correctly aligning the input polarization to the designated working axis is essential to achieve the specified extinction ratio, isolation, and low insertion loss.
What are the recommended installation and handling practices for the Lfiber high power PM isolator?
For reliable operation, mount the 58 × 28 × 26 mm package on a thermally conductive surface within the specified operating temperature range (+10 °C to +50 °C), and avoid rapid temperature cycling. Do not exceed the maximum tensile load of 5 N on the fiber pigtails; secure fibers so that no strain is transferred to the device. For high‑power CW systems, use fusion splicing rather than connectors wherever possible to reduce insertion loss and thermal load. If connectors are used, ensure they are clean and properly mated and select 900 µm loose‑tube pigtails instead of bare fiber so that the fiber does not have to support the connector weight. Always respect the specified average and peak power ratings, and if your application involves atypical pulse formats or environmental conditions, contact Lfiber for customized specifications or additional guidance.

Got more questions? Use the inquiry form to ask the supplier directly.

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