A lot of us maybe have some questions about optical laser, such as can we see the optical laser? or can we be blind by looking into active fiber? Hope this tutorial can answer about optical laser safety.
If you see on the transceiver label there is information about CLASS 1. CLASS 1 tell us about Laser Safety Level.
picture 1. Transceiver Label
Lasers are grouped into 4 main classes for safety :
- Class 1 - Completely harmless during normal use.
Class 1M - Also safe but we must be careful if we look using microscope or telescope.
- Class 2 - Only harmful if you intentionally stare into the laser, considered to be safe by blink reflex .
Example laser pointers and supermarket scanners.
- Class 3 - Should not be viewed directly.
Class 3R (new systems) or IIIA (old system), between 1 - 5mW, example high power purchased laser pointer.
Class 3B (new system) or IIIB (old system), limited to 500mW, requires a key and safety interlock system.
- Class 4 - Burns, melts, starts fires, etc.
Networking lasers operate in the infrared spectrum. Infrared can be further classifed as follows :
- IR-A (700nm - 1400nm), near infrared.
- IR-B (1400nm - 3000nm), shortwave infrared.
Laser safety levels are based on what can enter the eye and the human eye wasn't meant to see is IR.
Q : Can we be blind by looking into active fiber?
A : Since the transceiver or networking equipment such as Switch or Router are always use Class 1 safety, Its completely safe under all conditions.
Q : Can we see optical transceiver laser?
A : No, because the human eye only can see between 390 - 750nm. There is no telecom fiber signal directly visible to the human eye.
Q : Is there any trick to see the light in a fiber?
A : Most digital cameras actually can see in infrared. You can turn on your camera phone and hold it / focus in to the fiber (850nm wavelength), you can see the red light. You can try this on your TV remote control.
Q : Should we are wearing goggles in the data center?
A : The standard transceiver optics are always Class 1, its safe under all conditions. But don't hold a DWDM mux directly to your eye. We must be careful If we are using fiber microscope or telescope to see the fiber light.