CW
CW turns up in 2 fields: photonics, telecom & it. Here is what it means to the people in each one.
CW in photonics
Continuous Wave: laser operation with a steady output beam rather than pulses.
Continuous Wave, a laser whose output power is constant over time, as opposed to pulsed, Q-switched or mode-locked operation. Average and peak power are the same, so CW lasers are rated in watts and their damage specs in power per unit length or area. Many lasers can run either CW or modulated; quasi-CW means pulses long enough for the laser to reach the same steady state as CW, run at a low duty cycle to cut the heat load.
"Run it CW at 2 watts for the alignment, then switch the AOM on and go to 50 kHz pulsed."
CW in telecom & it
Continuous Wave, an unmodulated radio signal used primarily for Morse code transmission.
CW stands for continuous wave, an electromagnetic wave of constant amplitude and frequency. In radio operations, it refers to the transmission method where this carrier wave is simply switched on and off to form Morse code characters. Because it concentrates all transmitter power into a single narrow frequency, it can cut through heavy interference and propagate globally on minimal wattage.
"The band is too noisy for voice, so switch to CW and see if you can raise the maritime net."