Patent ID: 6921195

Claim:
A method for determining a characteristic of a device, the method comprising: obtaining a first temperature measurement (T surf ) in a first location of the device; obtaining a second temperature measurement (T hs ); computing the difference (ΔT) between said first temperature measurement and said second temperature measurement; and determining a characteristic of said device using at least one of the group including the temperature measurements and the temperature difference by determining one of optical power (P rad ), thermal impedance (Z T ), heat transfer coefficient (k), spontaneous emission efficiency (η spon ), stimulated emission efficiency (η stim ), and threshold current (I th ) in accordance with the formula: IV = ⁢ P cond + P conv + P rad = ⁢ ( Δ ⁢ ⁢ T Z T ) + ( Ak ⁡ ( T surf - T amb ) + ⁢ ( η spon ⁡ ( hv q ) ⁢ I th + η stim ⁡ ( hv q ) ⁢ ( I - I th ) + A ⁢ ⁢ σ ⁢ ⁢ T surf 4 ) wherein IV is the bias power; P cond is the thermal conduction power, and P conv is the thermal convection power, ΔT=T surf −T hs and is measured between the surface of the device and a nearby point on a heat sink, T amb is the ambient temperature, A is the device area, k is the convection heat-transfer coefficient, σ is the Stefan-Boltzmann coefficient, h is Planck's constant, v is the optical frequency, q is the elementary charge, and I is the applied current.