Patent ID: 11942763
Assignee: OSRAM OLED GMBH
Field: Optics (Instruments)
Classification: CPC H  B | IPC B  H

Claim 11:
12. A method for determining an optimum filling factor in a semiconductor laser with a range between 0.07 and 0.18 inclusive, comprising:
A) determining geometric dimensions of a still unstructured semiconductor layer sequence;
B) determining a threshold current density (Js), a specific surface conductivity (ρ), a steepness (Sh) of a laser characteristic curve and a maximum temperature (Tj) of an active zone of the semiconductor layer sequence;
C) determining and parameterizing a thermal connection of the semiconductor layer sequence to at least one heat sink;
D) inserting determined values into an equation or an equation system for an optical output power (P) and/or for a target operating current (Iop); and
E) determining a filling factor (FF) on a basis of the equation or the equation system taking into account a temperature (Ths) on a side of the semiconductor layer sequence towards the at least one heat sink, wherein the filling factor (FF) is a quotient of a width b of emitter strips and a periodicity N of the emitter strips,
wherein the filling factor (FF) and a thermal resistance (Rth), which results from the thermal connection of the semiconductor layer sequence to the at least one heat sink, are mutually dependent,
wherein further for an optical power (P) of the semiconductor laser, a threshold current (Is), an input voltage (Uop), an electrical series resistance (Rs), a length (L) of the emitter strips, a total width (w) of an envelope of the emitter strips, and an optical power loss (Ploss) holds true:

Iop=−(Uop−Sh)±√{square root over ((Uop−Sh)2−4Rs(IsSh−Tj−Ths/Rth))}/2Rs  (V)

P=Sh(Iop−Is)  (I)

P=RsIop2+UopIop−Ploss  (II)

Tj=Ths+RthPloss  (III)

Is=Js*L*w*FF 

Rs=ρ/L*w*FF 

the optical output power (P) is calculated by inserting the target operating current (Iop) from (V) into (I), the filling factor (FF) is then varied, dependence of laser input parameters results in different results relating to Iop and to the output power (P).