Variable Fiber Optical Attenuators, Polarization Maintaining
![](https://www.thorlabs.us/Images/GuideImages/6162_VOA50PM_3.jpg)
- Polarization-Maintaining, Inline, Variable Fiber Optic Attenuators
- Up to 50 dB Attenuation
- 630, 780, 1064, or 1310/1550 nm Center Wavelength
Adjustment Screw
Located on Top
VOA780PM-FC
VOA50PM-APC
FC/APC
FC/PC
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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, Inline, Variable Fiber Optical Attenuators
- Collimator-Based Manually Variable Attenuation
- 1 m Long PM Fiber Pigtail on Each Side
Thorlabs' Polarization-Maintaining Variable Optical Attenuators (PM VOAs) allow the user to manually vary the attenuation of a signal for precise power balancing in fiber circuits or evaluation of the dynamic range of measurement systems. Adjustment of the attenuation is achieved using the thumbscrew on the top of the housing.
The attenuator is comprised of an input fiber, collimating lens, blocking device, focusing lens, and output fiber. By turning the thumbscrew, the blocking device is shifted into the beam path, blocking part of the free-space beam (refer to the schematic to the right). Then, a second lens is used to couple light into the output fiber. Therefore, by turning the screw, one can manually alter the coupling efficiency until the desired attenuation is obtained.
All in-line PM VOAs have fiber pigtails with a Ø900 µm jacket and are available with 2.0 mm narrow key FC/PC- or FC/APC-connectorized fiber pigtails with the key aligned to the slow axis. For other connector styles or custom requests, please contact technical support.
Attenuation Range
Shown below is a sample attenuation curve obtained by testing the VOA780PM-APC. 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 specification was met. PM VOAs with other center wavelengths exhibit similar performance. Please note: changes in turning direction may cause a small offset in attenuator position due to backlash.
Posted Comments: | |
user
 (posted 2024-01-22 10:31:41.587) Hi
I would like to use this at high power (1 W). Where does the input power limitation comme from, the input connectors or the optical assembly in the middle?
If necessary, I can fuse the input/output fiber to my setup to avoid this limitation.
Best regards
François ksosnowski
 (posted 2024-01-22 12:43:33.0) Hello François, thanks for reaching out to Thorlabs. Both the connectors and the internal fiber terminations are using similar epoxies and will see similar thermal related limits due to the total power. At some point the epoxy will soften which can lead to drift of alignment, which increases the loss, and results in damage to the device. Unfortunately splicing won't get around this limit. user
 (posted 2018-01-30 10:26:40.157) Please make 980nm version. Thanks! tcampbell
 (posted 2018-01-31 08:43:19.0) Hello, thank you for contacting Thorlabs. I have posted this suggestion in our internal engineering forum. Feel free to email techsupport@thorlabs.com for help in finding a suitable solution for your application. |
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Item # | Operating Wavelength |
Attenuation Range |
Attenuation Resolution |
% Transmission Range |
Return Loss |
Max Power |
Insertion Loss |
---|---|---|---|---|---|---|---|
VOA630PM-FC | 630 ± 20 nm | 3.0 - 50 dB | 0.15 dB (Typical) | 0.001 - 50.1% | >40 dB | 300 mW | <3.0 dB |
VOA630PM-APC |
Item # | Extinction Ratio |
Operating Temperature |
Storage Temperature |
Fiber | Fiber Length |
Housing Dimensions |
---|---|---|---|---|---|---|
VOA630PM-FC | >16 dB | 0 to 70 °C | -40 to 85 °C | SM63-PS-U25D | 1 m Per Side | 26 mm x 18 mm x 8 mm |
VOA630PM-APC |
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Item # | Operating Wavelength |
Attenuation Range |
Attenuation Resolution |
% Transmission Range |
Return Loss |
Max Power |
Insertion Loss |
---|---|---|---|---|---|---|---|
VOA780PM-FC | 780 ± 20 nm | 2.1 - 50 dB | 0.15 dB (Typical) | 0.001 - 61.7% | >40 dB | 300 mW | <2.1 dB |
VOA780PM-APC |
Item # | Extinction Ratio |
Operating Temperature |
Storage Temperature |
Fiber | Fiber Length |
Housing Dimensions |
---|---|---|---|---|---|---|
VOA780PM-FC | >16 dB | 0 to 70 °C | -40 to 85 °C | SM85-PS-U25A | 1 m Per Side | 26 mm x 18 mm x 8 mm |
VOA780PM-APC |
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Item # | Operating Wavelength |
Attenuation Range |
Attenuation Resolution |
% Transmission Range |
Return Loss |
Max Power |
Insertion Loss |
---|---|---|---|---|---|---|---|
VOA1064PM-FC | 1064 ± 20 nm | 1.3 - 50 dB | 0.15 dB (Typical) | 0.001 - 74.1% | >45 dB | 300 mW | <1.3 dB |
VOA1064PM-APC |
Item # | Extinction Ratio |
Operating Temperature |
Storage Temperature |
Fiber | Fiber Length |
Housing Dimensions |
---|---|---|---|---|---|---|
VOA1064PM-FC | >18 dB | 0 to 70 °C | -40 to 85 °C | SM980PS-U25A | 1 m Per Side | 26 mm x 18 mm x 8 mm |
VOA1064PM-APC |
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Item # | Operating Wavelength |
Attenuation Range |
Attenuation Resolution |
% Transmission Range |
Return Loss |
Max Power |
Insertion Loss |
---|---|---|---|---|---|---|---|
VOA50PM-FC | 1310 ± 40 nm and 1550 ± 40 nm |
0.9 - 50 dB | 0.15 dB (Typical) | 0.001 - 81.3% | 50 dB | 300 mW | <0.9 dB |
VOA50PM-APC |
Item # | Extinction Ratio |
Operating Temperature |
Storage Temperature |
Fiber | Fiber Length |
Housing Dimensions |
---|---|---|---|---|---|---|
VOA50PM-FC | >18 dB | -5 to 70 °C | -40 to 85 °C | SM13-PS-U25D | 1 m Per Side | 26 mm x 18 mm x 8 mm |
VOA50PM-APC |