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

Please Wait

Overview
Attenuation Data
Feedback

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

Click to Enlarge
Click for Raw Data

Posted Comments:

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.

Narrowband, Single Mode Variable Optical Attenuators

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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
Fiber^a	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 Customer Inspired! SM Variable Attenuator, 630 nm, 50 dB, In-Line, FC/PC Connectors

$450.16

Today

VOA630-APC Customer Inspired! SM Variable Attenuator, 630 nm, 50 dB, In-Line, FC/APC Connectors

$471.80

Today

VOA780-FC Customer Inspired! SM Variable Attenuator, 780 nm, 50 dB, In-Line, FC/PC Connectors

$374.42

Today

VOA780-APC Customer Inspired! SM Variable Attenuator, 780 nm, 50 dB, In-Line, FC/APC Connectors

$397.14

Today

VOA850-FC Customer Inspired! SM Variable Attenuator, 850 nm, 50 dB, In-Line, FC/PC Connectors

$374.42

Today

VOA850-APC Customer Inspired! SM Variable Attenuator, 850 nm, 50 dB, In-Line, FC/APC Connectors

$397.14

Today

VOA980-FC Customer Inspired! SM Variable Attenuator, 980 nm, 50 dB, In-Line, FC/PC Connectors

$312.73

Today

VOA980-APC Customer Inspired! SM Variable Attenuator, 980 nm, 50 dB, In-Line, FC/APC Connectors

$336.54

Today

VOA1064-FC Customer Inspired! SM Variable Attenuator, 1064 nm, 50 dB, In-Line, FC/PC Connectors

$312.73

Today

VOA1064-APC Customer Inspired! SM Variable Attenuator, 1064 nm, 50 dB, In-Line, FC/APC Connectors

$336.54

Today

Dual Band, Single Mode Variable Optical Attenuators

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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
Fiber^b	SMF-28e
Dimensions	38 mm x 30 mm x 19 mm

1 m Fiber Pigtail on Each Side

View All »Matching Part Numbers

Variable Fiber Optical Attenuators, Single Mode

Features

Attenuation Range

Narrowband, Single Mode Variable Optical Attenuators

Dual Band, Single Mode Variable Optical Attenuators