Products Home / Fiber Components / Fiber Optic Attenuators / Variable Fiber Optical Attenuators, Single ModeVariable 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
| 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.
Click to Enlarge
For narrowband VOAs, turning the adjustment screw moves the blocking device up and down in order to achieve the desired attenuation.
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.
| 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. |
ZoomThis 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 | ||||
Zoom| 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 | ||
SM Variable Optical Attenuators