Variable Optical Attenuators
DiCon Fiberoptics, a recognized leader in designing and manufacturing optical components, offers an advanced lineup of fiber optic attenuators for use in numerous applications.
Variable Optical Attenuator (VOA) Applications
Power equalization between multiple channels
Power stabilization of sources
Signal to noise optimization
Shuttering of sources
To meet the fiber optic attenuator needs of different applications across multiple markets, DiCon carries products in four separate technology platforms, each with a range of configurations.
MEMS Variable Optical Attenuator (VOA)
DiCon’s MEMS variable optical attenuator is a high quality VOA based on DiCon’s industry proven MEMS mirror technology. These operate by collecting and collimating light from an input fiber and then reflecting this light off of an ultra-stable and reliable, single-axis DiCon MEMS mirror. The reflected light is directed to the output fiber and a precise level of attenuation is achieved by partially misaligning the light being coupled to the output fiber. DiCon’s MEMS VOAs are GR-1221 qualified, and their high quality, long life, and high reliability, as well as their ability to be customized to the application, make them ideal for either OEM or test & measurement applications.
Precision Variable Attenuator
DiCon’s Precision Variable Attenuator operates by using a neutral density filter placed in the light path. This neutral density filter varies in attenuation along its length and a high precision stepper motor is used to move the filter to the requested attenuation level. This type of fiber optic attenuator is ideal for multimode fiber applications because the neutral density filter attenuates all modes equally, and results in stable attenuation and linear response.
VOA Technology Comparison Matrix ¹
| MEMS | Precision Variable | |
| Max Attenuation | 40 dB | 30 or 60 dB |
| Excess Loss | 0.8 dB max. | 1.3 dB max. |
| Resolution | Analog (2) or 0.01 dB (3) | 0.01 dB max. |
| Durability | 1 billion cycles min. | (4) |
| Recommended Fiber Type | Single mode (Multimode Available) | Multimode |
| Standard Size |  |
 |
| Qualification | GR-1221 | (4) |
| Control Method | Analog Voltage RS-232 or I²C (5) | I²C |
| Response Time | 2 ms max. | 50 ms min. 1400 ms max. |
1. Single mode fiber specifications shown for comparison.
2. MEMS VOA components have no minimum resolution, as they are analog controlled devices.
3. MEMS VOA modules have a 0.01 dB resolution.
4. Intended for test and measurement applications.
5. MEMS VOA components use direct analog voltage, while MEMS VOA modules use RS-232 or I2C.