Python simulation and analysis tool for photonic integrated circutis and components, including:
- Feedback control loop, Pound-Drever-Hall (PDH), phase lock loop (PLL) and optical phase loop (OPLL)
- Semiconductor laser rate equation model, based on The Book Diode Laser and Photonic Integrated Circuits
git clone git@github.com:kaikai-liu/pyphotonicsims.git
cd pyphotonicsims
make install
The laser simulation model is based on this paper, Behunin, Ryan O., et al. "Fundamental noise dynamics in cascaded-order Brillouin lasers." Physical Review A 98.2 (2018): 023832.
- Laser rate equations for SBS cascaded emission
$$\frac{da_m}{dt} = (i\Delta\omega - \gamma/2 + \mu(|a_{m-1}|^2 - |a_{m+1}|^2))a_m + \delta_{m0}i\sqrt(\gamma_{ex})F$$ - Laser metrics calculation: cavity
$Q$ , cavity loss rates such as$\gamma = \omega/Q$ (total),$\gamma_{in} = \omega/Q_{in}$ (intrinsic) and$\gamma_{ex} = \omega/Q_{ex}$ (coupling/external), threshold$P_{th}$ , efficiency$\eta$ , minimum ST linewidth$\nu_{ST}$ $$P_{th} = \frac{h\nu\gamma^3}{8\mu\gamma_{ex}} $$ $$\eta_{S1} = (\frac{\gamma_{ex}}{\gamma})^2$$ $$\nu_{ST,min} = \frac{n_0\gamma}{2\pi}$$
The left plot shows the frequency noise performance in a laser stabilization setup, where the free-running laser (blue trace) is frequency locked to an optical cavity.
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The left-side plot demonstrates (1) the locking bandwidth is about 1 MHz, (2) within the loop bandwidth the laser tracks the optical cavity and thus the laser noise is limited by the cavity's thermorefreactive noise (TRN), (3) the in-loop noise has contribution from free-running laser noise and the photodetector (PD) noise.
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The right-side plot takes a closer look at the in-loop noise contribution from all blocks of the lock loop, such as the photodetector (PD) or frequency noise discriminator, the servo and the laser.
The plot below shows the phase noise performance of a Mini-Circuit ZOS50+ VCO locked to an LO.
