GAOTek Handheld Variable Optical Attenuator

$460.00 USD

This variable optical attenuator is designed with single-mode fiber to continuously attenuate the optical signal and can be used in the digital systems of communication devices and CATV systems.


Key Features

  • Built-in neutral density filter
  • Attenuation range is from 2.5 dB to 60 dB
  • Stepwise attenuation; 0.05 dB steps
  • Portable, rugged, lightweight and easy to use
  • Low battery power indication
  • Memorizes the attenuating value and step on shut down and restores the values on next power up
  • Combines the functions of both an attenuator and an optical power meter
  • Optical auto-off function deactivates after 10 minutes of idle time
  • Displays absolute and relative attenuation value
  • Wavelength, input power, output power, current attenuation and selected step size can be displayed simultaneously on LCD



Technical Specifications

Wavelength Range 1260 nm  ~ 1650 nm
Fiber Model 9/125 µm SM
Connector FC/PC
Calibrated Wavelength 1310 nm/1490 nm/1550 nm/1625 nm
Attenuation Range 2.5 dB to 60 dB
Resolution 0.05 dB
Minimum Insertion Loss < 2.5 dB
Linearity ± 0.5 dB
Repeatability ± 0.2 dB
Overall Attenuation Accuracy ± 0.8 dB
Return Loss at Input/output >35 dB (typical value: 40 dB)
Maximum Acceptable Input +20 dBm
Rechargeable Battery 7.4 V
Power Supply Adapter 7 V ~ 8.5 V
Weight 7.05 oz. (200 g)
Dimensions 8.27 in x 6.10 in x 2.17 in (210 mm x 155 mm x 55 mm)
Humidity 0 %  to  85 %
Operating Temperature 32 ˚F to 104 ˚F (0 ˚C to 40 ˚C)
Storage Temperature 14 ˚F to 140 ˚F (-10 ˚C to +60 ˚C)



Additional Information


  • Key: To turn on/off the unit press the key for 2 seconds. This key is also used to activate or deactivate the auto-off function.
  • MENU/ENTER” Key: Menu/confirm.
  • “▲Key: This key is used to select the function or to increase the value.
  • “▼Key: This key is used to select the function or to decrease the value.
  • CANCEL” Key: This key is used to Exit/cancel the operation.
  • “λ” Key: Switch the wavelength from one value to another value.
  • “Rotating Dial” Key: Rotating dial is used to rotate in clockwise to increase the attenuation value, or to decrease the attenuation value. The attenuation step is in the range of 0.5 dB.


  • To turn on the unit press “” this key which then displays the absolute or relative attenuation value. This key is also used to activate or deactivate auto-off function.
  • The unit shut down automatically if the unit is idle for 10 minutes.

                              Picture: 1

                       Picture: 2

Edit the wavelength

To edit the wavelength click the option “edit the wavelength” and press “MENU/ENTER” key to display the status of wavelength: 1300 nm/1310 nm/1490 nm/1550 nm/1625 nm.

               Picture: 3

               Picture: 3.1

To change the status of the wavelength press “MENU/ENTER” key again. It doesn’t show the hidden wavelength when switching the wavelength.

            Picture: 4

Set “REF”

Under the option, press “MENU/ENTER” key to set reference value.

  • Select option 1, to set the current attenuation value as the reference value. Press “MENU/ENTER” key back to picture: 2
  • Select option 2, to edit the value as the reference value.

              Picture: 5

  • To increase or decrease the value press “▲“▼
  • To choose the value to be revised press “MENU/ENTER” key.

               Picture: 6

Display the relative/absolute value

                 Picture: 7

  • Choose the absolute value, it is back to Picture: 1 interface.
  • Choose the relative value, it is back to Picture: 2 interface.

LCD backlight adjustment

                Picture: 8

Press “▲“▼key to adjust the lightness of LCD screen as of Picture: 8


Insert the battery in unit. Press “” the key to turn on the unit. It will show the absolute or relative attenuation value.

               Picture: 9

When the battery is low or empty “”, take out the battery and charge it on time and when it’s not working, insert the power supply to power the whole unit. “” this icon denotes the external power is under use. The auto-shut down function is invalid if using the external power.

  • Take out the dust-proof cap and connect it to the light source. Press “λ” key to select the wavelength.
  • Set 2.5 dB as shown in Picture: 9 as the reference value.

To enter the menu press “MENU/ENTER” key.

To set or edit the “REF” level press “▼key and choose the option.

  • Select option 1 “Set REF Level” and set the REF value as 2.50 dB.
  • To confirm the value press “MENU/ENTER” key and return to interface Picture: 11.
  • To cancel the operation press “CANCEL” key.

             Picture: 10

               Picture: 11

Press “” key to select option 2 “Edit REF value”. User could define the REF value. Press “MENU/ENTER” key to edit the value as shown in Picture: 12. Press “▲“▼to change the value and press “MENU/ENTER” key to choose the digits to be revised and press it again to save. Press “CANCEL” key to exit or cancel.

            Picture: 12

After setting the REF value as 2.5 dB in the Picture: 11 rotate clockwise using the “Rotating Dial”, the attenuation step is 0.5 dB. If continuously rotated to attenuation value -19.15 dBr as shown in Picture: 13, it means this optical link relatively attenuates -19.15 dBr.

             Picture: 13

After the test, press “” this key to turn off the unit and cover back the dust-proof cap.


  1. It is important to keep all the connectors and surfaces free from oil, dirt or other contamination for proper operation.
  2. Keep using one type of adapter to avoid excess loss from different connectors.
  3. Turn off the unit and cover dust proof cap after the test.
  4. Use the power adapter within regulated voltage when using external power
  5. Take the battery out when it is not in use for a period of time.


Description Possible Reason Method
No display after turning on the unit Battery is weak/Fail to turn on the unit Turn on the unit once again/ Charge battery
Wrong test result Dirty connection or bad connection Clean the connector and

Re-connect the fiber.


  • Ensure the connector is clean before the test.
  • Cover the dust-proof cap when the connector is not in use
  • Use the original charger to charge the battery. Otherwise, it leads to serious damages.


Additional information

Weight 0.99 kg

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