Fig. 5: Peak search, comb acquisition, and tracking in the MZI-based DeMux.
From: Integrated multi-port multi-wavelength coherent optical source for beyond Tb/s optical links
a In the peak search process (yellow regions), the comb is deactivated and for each MZI, the tunable pump laser is tuned to the wavelength of the corresponding target comb line and the MZI phase shifter voltage is ramped up covering the tuning range and the count number corresponding to the voltage that aligns the peak in the MZI response to the corresponding target wavelength is recorded. During the tuning process (the light green regions), while the comb is inactive, the counter counts to the recorded count number aligning the MZI with the target wavelength. b In comb acquisition phase (red dots), the comb is activated and the monitor voltage corresponding to the output power of each MZI, the locking reference voltage, is stored in a memory unit. During the tracking process (the light green region), MZIs are sequentially selected and, if needed, the monitor voltage of each MZI is locked to the corresponding locking reference voltage using the counter up/down signal in a feedback loop.
