Nd:YAG Fiber Isolators (SM Fiber)


Nd:YAG Fiber Optic Isolators with SM Fiber (1064 nm)

  • Center Wavelength at 1064 nm
  • Isolation up to 38 dB
  • FC/APC Connectorized Unconnectorized SM Fiber
  • OEM and Build-to-Order Fiber Isolators Available


  • Minimize Feedback into Optical Systems
  • Operating Ranges of 1054 - 1074 nm or 1059 - 1069 nm
  • At Least 0.8 m of SM Fiber on Both Sides
  • Available with 2.0 mm Narrow Key FC/APC Connectors or Bare Ends
  • Designed for CW Applications
  • Each Unit is Individually Tested
  • Fiber to Free-Space Option Available
  • Custom Isolators Available 

Fiber isolators protect light sources from back reflections and signals that can cause intensity noise and optical damage. Optical isolators, also known as Faraday isolators, are magneto-optic devices that preferentially transmit light in the forward direction while absorbing or displacing light propagating in the reverse direction (see the schematic below). Please see the Isolator Tutorial tab for an explanation of the operating principles of a Faraday isolator.

Isolator Schematic A polarization independent isolator. Light is deflected away from the input path and stopped by the housing.

Thorlabs' polarization-independent Nd:YAG isolators, sold on this page, are compatible with single mode (SM) fibers. In contrast, our polarization-dependent Nd:YAG isolators are designed to connect to polarization-maintaining (PM) fibers. Our high-power units are built using a specialized fiber end face process that increases the maximum power. A length of 0.8 m of fiber is built in to each side of the isolator, and an arrow on the body indicates the transmission direction. In addition, each unit is tested before shipment to ensure compliance with our specifications and a complete test report comes with every serialized part.


30 W Polarization-Independent Fiber to Free-Space Isolator with Red Aiming Laser Pass Through

Item # IOK-1064-LMA25-CRED
Polarization Independent
Fiber Type SM
Center Wavelength 1064 nm
Operating Range 1054 - 1074 nm
Max Powera 30 W (CW)
10 kW (Peak)
25 W (Avg.)
Isolation >30 dB
Performance Graph
(Click for Details)
Insertion Loss <0.45 dB
Polarization Dependent Loss (PDL) <0.2 dB
Return Loss >50 dB
Fiber LMA-25
  • For CW or pulsed light sources.

The IOK-1064-LMA25 is a fiber-to-free-space isolator for high-power applications in the 1064 nm range. Using our experience in high-power fiber manufacturing, this isolator has been fabricated to withstand CW laser powers up to 30 W. This isolator has the added benefit that a red alignment laser with transmission in the 633 to 690 nm range can be coupled into the LMA25 fiber prior to entering the isolator. This aiming feature is extremely useful when working with a free-space IR beam.

Mounting holes on the output port allow components such as beam expanders to be attached. Without a beam expander, a Ø0.5 mm collimated beam will exit the isolator centered on the body with a divergence of 3 to 4 mrad.


1064 nm Polarization-Independent Fiber Optic Isolators

Item # IO-H-1064B
Polarization Independent Independent Independent
Fiber Type SM SM SM
Center Wavelength 1064 nm 1064 nm 1064 nm
Operating Range 1059 - 1069 nm 1054 - 1074 nm 1054 - 1074 nm
Max Power 300 mW (CW)a 3 W (CW)a 10 W (CW)b
Isolation ≥30 dB 33 - 38 dB 30 - 36 dB
Performance Graph
(Click for Details)
Insertion Loss ≤1.8 dB (IO-H-1064B)
≤2.1 dB (IO-H-1064B-APC)
0.7 - 1.3 dBc 0.8 - 1.5 dB
Polarization Dependent Loss (PDL) ≤0.15 dB ≤0.15 dB ≤0.25 dB
Return Loss (Input/Output) ≥55/50 dB (IO-H-1064B)
≥50/45 dB (IO-H-1064B-APC)
>50 dB >50 dB
Fiber HI1060 HI1060 HI1060


  • Not recommended for high-power pulsed applications.
  • Ideal for high-power CW or pulsed applications.
  • Insertion Loss for IO-F-1064



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