ALS (Automatic Laser Shutdown) is a safety mechanism used in DWDM (Dense Wavelength Division Multiplexing) and other optical communication systems to automatically disable the laser under specific conditions to prevent eye damage or equipment harm.
Why ALS is Important
• DWDM systems use high-power lasers, which can be hazardous to human eyes and optical components if exposed directly.
• Fiber disconnection or open connectors can leak laser light.
• ALS helps automate shutdown of the laser in such events.
How ALS Works
Fiber break or unplugged - Laser turns off immediately
Loss of signal (LOS) - Laser shutdown
Link fault detected - Laser disabled
Remote end signal loss - Both ends shut lasers (mutual ALS)
• Once the fault is resolved and fiber is reconnected, ALS must be reset (manually or automatically depending on configuration).
ALS in Practice
• Commonly implemented in optical transponders, amplifiers, and DWDM terminals.
• Helps ensure network safety and protects maintenance personnel.
• May be disabled during commissioning or testing, but it’s required in production for safety compliance.
LinkedIn: 