Tool · Laser characterization

Junction Temperature Calculator

Extract junction temperature rise and thermal resistance from a measured DFB wavelength shift ΔT_j = Δλ / (dλ/dT), or predict T_j from a known R_th.

Drive current (mA)

Forward voltage V_f (V)

Optical power out (mW)

Dissipated power P_diss = I·V_f − P_opt = 178 mW

Wavelength tuning dλ/dT (nm/°C)

From the pulsed calibration; ~0.09–0.10 for 1550 nm DFBs.

Measured shift Δλ, CW − pulsed (nm)

Result

Junction temperature rise ΔT_j: 6.5 °C
Thermal resistance R_th: 36.4 K/W

Method, calibration procedure, and the systematic errors to avoid are covered in the companion article Measuring laser diode junction temperature.

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