What's inside:
How an InP DFB laser works: multiple quantum wells, the L-I curve, spontaneous vs stimulated emission
DFB grating design: mode-hopping, grating spacing, refractive index shifts, and why κL is the key knob
Laser linewidth and cavity length: the Schawlow-Townes-Henry equation and the efficiency vs linewidth tradeoff
Why low power DFB lasers for telecom (DML, EML) are designed differently
The four walls of UHP lasers: heat, linewidth widening, getting the light out, and catastrophic optical damage
Who it's for: investors and engineers who want to cut through the noise on CPO lasers and think for themselves.