Variable Fiber Optical Attenuators, Single Mode


  • Single Mode, In-Line Variable Fiber Optic Attenuators
  • Up to 50 dB Attenuation
  • Narrowband or Dual-Band VOA Models for 630 - 1550 nm
  • Available With No Connectors, FC/PC Connectors, or FC/APC Connectors

Adjustment Screw
Located on Backside

VOA50

Dual Band VOA

VOA850-APC

Narrowband VOA

Adjustment Screw
Located on Top

Related Items


Please Wait
Fiber Optic Attenuator Selection Guide
SM
 Electronic VOAs for System Integration
Digital VOAs
Tabletop EVOAs with Power Lock
Manually Variable Attenuators
Fixed-Value Attenuators
MM Fixed-Value Attenuators
Manually Variable Attenuators
PM
 Electronic VOAs for System Integration
Manually Variable Attenuators

Features

  • Bi-Directional, In-Line Variable Fiber Optical Attenuators (VOA)
  • Narrowband VOA Models for 630 nm, 780 nm, 850 nm, 980 nm, and 1064 nm Operating Wavelengths
  • Dual-Band VOA Models for 1310 / 1550 nm
  • Collimator-Based Manually Variable Attenuation
  • 1 m Long Single Mode Fiber Pigtail on Each Side

Thorlabs' Single Mode Variable Optical Attenuators allow the user to manually vary the attenuation of the signal in the fiber as it is transmitted through the device. These VOAs can be used to to precisely balance the signal strengths in fiber circuits or to balance an optical signal when evaluating the dynamic range of the measurement system. The maximum specified attenuation is achieved within 10 turns of the adjustment screw. Please see the Attenuation Data tab for more information.

All in-line VOAs have single mode fiber pigtails with a Ø3 mm jacket. The VOAs are offered unterminated or terminated with 2.0 mm narrow key FC/PC or FC/APC connectors. For other connector styles or custom requests, please contact Technical Support.

Each attenuator has a lens to collimate the light from the input fiber. A blocking device or window can be manually adjusted by a screw (see schematics below). Then, a second lens is used to couple light into the output fiber. Thus, the coupling efficiency is changed until the desired attenuation is obtained.

Narrowband VOAs

Schematic for Operation of a Variable Optical Attenuator
Click to Enlarge
For narrowband VOAs, turning the adjustment screw moves the blocking device up and down in order to achieve the desired attenuation.

Dual Band VOAs

Schematic for Operation of a Variable Optical Attenuator
Click to Enlarge
For dual band VOAs, turning the adjustment screw rotates the window, causing a beam path deviation that changes the coupling efficiency into the output fiber.

Attenuation Range

Shown below is a sample attenuation curve obtained by testing the VOA630-FC. The device was tested with the adjustment screw in the closed position (blocking the light). The screw was then turned counterclockwise in quarter turns until the attenuation spec was met. Please note: changes in turning direction may cause a small offset in attenuator position due to backlash.

Attenuation Range of VOA630-FC
Click to Enlarge
Click for Raw Data


Posted Comments:
Silas Eul  (posted 2024-02-20 14:42:01.07)
Why is there no narrow band SM-VOA for 1550nm? The PDL of the dual Band VOAs makes them unusable for my use case. The narrow band PM-VOA even exists for 1550nm but is not compatible with my setup due to the pm fibres.
jdelia  (posted 2024-02-22 08:57:20.0)
Thank you for contacting Thorlabs and for providing this valuable feedback. While this is not something we currently offer, I would be happy to forward your request to our design engineers via our internal suggestion forum for consideration as a future product.
Arthur van Wijk  (posted 2023-08-30 08:30:30.7)
Dear people at Thorlabs, The VOA's have holes in them, apparently to mount them. Do you have brackets for this purpose, to mount these onto breadboards?
cdolbashian  (posted 2023-09-11 01:42:54.0)
Thank you for reaching out to us with this inquiry! The 'thru-holes' on these components are designed for 4-40 or m3 cap screws. The easiest way to mount this to a optical table surface would be with a universal base plate, such as the UBP1. I have contacted you directly to discuss other options.
Yutong Feng  (posted 2020-10-08 07:41:41.077)
Hello, could Thorlabs provide a higher power model for this variable attenuator at 980 nm? Thank you.
YLohia  (posted 2020-10-08 03:02:49.0)
Thank you for contacting Thorlabs. Custom items can be requested by clicking on the Request Quote button above or by emailing your local Thorlabs Tech Support team (in your case techsupport.uk@thorlabs.com). We will contact you directly to discuss the feasibility of offering this.
Jana Morrison  (posted 2020-05-14 14:02:32.22)
Hello - do you take custom orders? I'm interested in a single mode, variable fiber optical attenuators with a 532nm wavelength.
YLohia  (posted 2020-05-20 01:56:53.0)
Hello Jana, custom items can be requested by emailing techsupport@thorlabs.com.
Joseph Baltan  (posted 2019-05-02 09:20:27.797)
Dear Sir Regarding the limitation of input power (300 mW), where does it come from? The fiber FC-PC connector or the device itself? So if I increasse a little bit the power (arround 500 mW) what do I risk more, burning the fiber connector facets or damaging the component itself? I thank you in advance, Joseph Baltan
YLohia  (posted 2019-05-02 09:37:36.0)
Hello Joseph, thank you for contacting Thorlabs. The max power rating is limited by the connector to 300mW (due to the epoxy). At higher powers, you would run the risk of damaging the connector. The fiber and the components can take more power.
boris.khoury  (posted 2015-10-29 16:00:09.047)
We purchase atm OZOPTICS attenuators for blue region. Are there any plans for blue VOA like 405nm, 460nm, 480nm? Insertion losses of 50% are for most application no problem in case of coupling problems.
besembeson  (posted 2015-10-29 06:08:11.0)
Response from Bweh at Thorlabs USA: Thanks for the feedback. We don't offer these yet but we are reviewing the idea.
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Narrowband, Single Mode Variable Optical Attenuators

This is our selection of narrowband single mode variable optical attenuators. For our dual-band single mode VOA models, please see below.

FC/PC Connectors VOA630-FC VOA780-FC VOA850-FC VOA980-FC VOA1064-FC
FC/APC Connectors VOA630-APC VOA780-APC VOA850-APC VOA980-APC VOA1064-APC
Operating Wavelength 630 nm 780 nm 850 nm 980 nm 1064 nm
Wavelength Range 620 - 650 nm 760 - 800 nm 830 - 870 nm 960 - 1000 nm 1044 - 1084 nm
Attenuation Range 3.0 - 50 dB 2.1 - 50 dB 1.8 - 50 dB 1.5 - 50 dB 1.3 - 50 dB
Attenuation Resolution 0.15 dB (Typical)
% Transmission Range 0.001 - 50.1% 0.001 - 61.7% 0.001 - 66.1% 0.001 - 70.8% 0.001 - 74.1%
Insertion Loss ≤3.0 dB ≤2.1 dB ≤1.8 dB ≤1.5 dB ≤1.3 dB
Return Loss ≥40 dB
Max Power 300 mW
Operating Temperature 0 to 70°C
Storage Temperature -40 to 85°C
Fibera SM600 HI780 SM800 HI1060 HI1060
Dimensions 26 mm x 18 mm x 8 mm
  • 1 m Fiber Pigtail on Each Side
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
VOA630-FC Support Documentation
VOA630-FCCustomer Inspired! SM Variable Attenuator, 630 nm, 50 dB, In-Line, FC/PC Connectors
$494.17
3 Weeks
VOA630-APC Support Documentation
VOA630-APCCustomer Inspired! SM Variable Attenuator, 630 nm, 50 dB, In-Line, FC/APC Connectors
$517.94
3-5 Days
VOA780-FC Support Documentation
VOA780-FCCustomer Inspired! SM Variable Attenuator, 780 nm, 50 dB, In-Line, FC/PC Connectors
$411.03
3-5 Days
VOA780-APC Support Documentation
VOA780-APCCustomer Inspired! SM Variable Attenuator, 780 nm, 50 dB, In-Line, FC/APC Connectors
$435.97
3-5 Days
VOA850-FC Support Documentation
VOA850-FCCustomer Inspired! SM Variable Attenuator, 850 nm, 50 dB, In-Line, FC/PC Connectors
$411.03
3-5 Days
VOA850-APC Support Documentation
VOA850-APCCustomer Inspired! SM Variable Attenuator, 850 nm, 50 dB, In-Line, FC/APC Connectors
$435.97
3-5 Days
VOA980-FC Support Documentation
VOA980-FCCustomer Inspired! SM Variable Attenuator, 980 nm, 50 dB, In-Line, FC/PC Connectors
$343.31
3-5 Days
VOA980-APC Support Documentation
VOA980-APCCustomer Inspired! SM Variable Attenuator, 980 nm, 50 dB, In-Line, FC/APC Connectors
$369.44
3-5 Days
VOA1064-FC Support Documentation
VOA1064-FCCustomer Inspired! SM Variable Attenuator, 1064 nm, 50 dB, In-Line, FC/PC Connectors
$343.31
3-5 Days
VOA1064-APC Support Documentation
VOA1064-APCCustomer Inspired! SM Variable Attenuator, 1064 nm, 50 dB, In-Line, FC/APC Connectors
$369.44
3-5 Days
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Dual Band, Single Mode Variable Optical Attenuators

Item # VOA50 VOA50-FC VOA50-APC
Termination None FC/PC FC/APC
Operating Wavelengths 1310 ± 20 nm / 1550 ± 20 nm
Attenuation Range 1.5 - 50 dB
Attenuation Resolution 0.1 dB (Typical)
% Transmission Range 0.001 - 70.8%
Insertion Loss ≤1.5 dB
Return Loss >55 dB
PDL <0.2 dB
Max Power 300 mW
Operating Temperature 0 to 60 °C
Storage Temperature -40 to 85 °C
Fiberb SMF-28e
Dimensions 38 mm x 30 mm x 19 mm
  • 1 m Fiber Pigtail on Each Side
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
VOA50 Support Documentation
VOA50SM Variable Attenuator, 1310/1550 nm, 50 dB, In-Line, No Connectors
$287.49
3-5 Days
VOA50-FC Support Documentation
VOA50-FCSM Variable Attenuator, 1310/1550 nm, 50 dB, In-Line, FC/PC Connectors
$313.61
3-5 Days
VOA50-APC Support Documentation
VOA50-APCSM Variable Attenuator, 1310/1550 nm, 50 dB, In-Line, FC/APC Connectors
$338.56
3-5 Days
Additional Fiber Optic Attenuators
  • SM Electronic VOAs with Power Lock

  • SM Digital VOAs

  • SM Electronic VOAs for System Integration

  • SM Variable Optical Attenuators

  • SM Fixed Optical Attenuators

  • MM Fixed Optical Attenuators

  • MM Variable Optical Attenuators

  • In-Line MM Fiber Optic Attenuators

  • PM Electronic VOA for System Integration

  • PM Variable Optical Attenuators