GAOTek Optical Light Source with Two Wavelengths

This Optical Light Source with Two Wavelengths

provides modulated output in two wavelengths (1310 nm/1550 nm)

for measuring the optical loss in a fiber cables.



The GAOTek Optical Light Source with Two Wavelengths is a portable optical fiber light source providing user modulated output in two wavelengths which deals with the transmission of light through transparent fiber. The device is equipped with an optical detector with a diameter of 0.03 in (1.0 mm) which ensures the stability and reliability of the device. This portable tester is used for the installation, debugging, and maintenance of fiber networks. It is widely used in the fields of cable construction and maintenance, optical fiber transmission, optical fiber communication, fiber optical sensors, and CATV.

Key Features

  • Compact size and easy to carry
  • Works with optical power meter
  • Provides 2 output wavelengths which can be set according to customer needs (1310 nm/1550 nm)
  • CW, CW, 270 Hz, 1 KHz, 2 KHz modulation output
  • High stability of the output power
  • Stable output wavelength
  • Large LCD, easy operation
  • 5 V battery with a service life of 200 hours
  • Standard FC/SC/ST interfaces that do not require an adapter
  • Automatic shut-off and backlight functions
  • Low battery indicator
  • User-defined self-calibration function
  • Dust cover to protect the connectors from dust

Technical Specifications

Wavelength 1310 nm, 1550 nm
Emitter Type FP-LD
Output Power -7 dBm
Modulation Frequencies CW/270 Hz, 1 kHz, 2 kHz
Fiber Type SM/MM
Optical Connector FC/SC/FC
Automatic Shut-down Time 15 min
Power Supply 1.5 V x 3 pcs
Overall Dimensions 6.29 in x 2.95 in x 1.25 in (160 mm x 75 mm x 32 mm)

Additional Information


  • Detect and locate fiber fault
  • Measuring power output
  • Delete repeated word loss in fiber cable or device
  • Fiber installation and maintenance
  • Fiber transmission and telecommunication field

 Panel Description

  1. Power button: If the device is not used for 1 hour, the system will automatically shut-down. To disable the shutdown function, short press the power button. To turn off the device, hold down the power button for a few seconds.
  2. Mode: Press the button to select desired frequency.
  3. Wavelength: Press the desired wavelength button, the device will emit light source of either 1310 nm or 1550 nm.
  • “Wavelength 1310” button

When this button is pressed, the light source will turn on the wavelength of 310 nm.

  • “Wavelength 1550” button

When this button is pressed, the light source will turn on the wavelength of 1550 nm.

  1. Calibrate: Long press the calibration button to keep current value as reference power value, and short press to be changed into relative power loss. The values will be shown on the top right. The unit is dB.
  2. “Auto-off”: Press the button with “Auto-off” icon indicating it is working and will be shown at the lower left of screen. Pressing the button again will disable the function.
  3. Backlight: When the device is turned on, the backlight will be on. If for a long time no action is performed, it will shut down.


Cleaning connector (probe)

  1. Open the dust cap.
  2. Slowly remove (unscrew) the connector adapter.
  3. Wipe the surface with cotton swabs 2.5 mm m soaked with alcohol.

Important: When cleaning the connector (probe), to avoid damage to it and to maintain the accuracy of measurements, do not apply much effort. After cleaning, immediately close the dust cover.

Installing and Replacing Batteries

  1. Use only 1.5 V DC batteries (3 pcs).
  2. To prevent damage to the appliance, remove the batteries if the device is not being used for a long time.

Attention: The device has a charging port; the user can charge the device only when using batteries. Do not charge while using disposable batteries.


To ensure the accuracy of the measurements, calibrate the instrument every year, as well as when you notice a deviation in its operation.


  • Do not expose the device to direct sunlight rays.
  • Do not look at the laser while it is running.
  • Do not operate the appliance at high temperature.
  • Clean the connector before use.
  • When the fiber cable is connected, do not press or pull the connector.
  • After turning off the appliance, wear a dustproof cover.
  • If the appliance is not to be used for a long time, remove the batteries from it.

Common Faults and Troubleshooting

Malfunction Possible Cause Remedy
Inaccurate measurement capacity Wavelength disparity Change work wavelength
Device or screen display does not turn on Battery defect Replace the battery
Faint glow of the display screen Battery defect Use adaptor or replace the battery
Instability of power Lack of prior laser heating


Turn on the device, establish a working wavelength, repeat the test in 30 minutes


Low output power source Source connector light is not cleaned Clean the connect light source

Standard Accessories

GAO-VLS-103 Optical Light Source 1 pc
Instruction Manual 1 pc
Battery (1.5 V AA) 3 pcs
Cotton swabs for cleaning 1 packet
Toolbox 1 pc
Box 1 pc