$cavitygainedge

$cavitygainedge command is used to help to calculate the cavity gain in the end of gain calculation.
The input format is

$cavitygainedge
R1  R2  cavity-Length

After obtaining the intrinsic gain of laser diode structure. The program calculate the optical mode and also calculate the
$\Gamma$ in each ddcc layer. Ideally, the cavity can be calculated by

$g_{cav} = \sum \Gamma_{QW} \times gain$. 

Effective absorption loss can be calculated by

$\alpha_{eff}= \Gamma_{i,loss layer} \times \alpha_{i}$. 

By the formula, can know that to obtain the gain

$g_{cav}  > \alpha_{eff} - \frac{1}{2L}\times ln (R1\times R2)$.