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Variable Fiber Optical Attenuators, Single Mode
Dual Band VOA
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.
Dual Band VOAs
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.
This is our selection of narrowband single mode variable optical attenuators. For our dual-band single mode VOA models, please see below.