We will now move on to describing tips for Block Mode simulations.
As described earlier in the course, Block Mode time domain simulations are best suited
for photonic circuits with unidirectional propagation.
In the case of bidirectional propagations, the elements need to be well separated so
that the feedback or the reflected signal has a delay greater than the duration of a
In order to run a time domain simulation in Block Mode, we have to set the value of the
“output signal mode” property of the Root Element to “block”.
The length of the block is defined by the “time window” property.
This combined with the “sample rate” property determines the total “number of samples”
in the block.
The “sample rate” is a global property and by default the elements inherit their
sample rates from the Root Element, they can also have their own local values for the sample
If the local sample rate of an element is different from the global sample rate, then
the simulator will automatically handle the resampling and merging of the different optical
signals from different elements.
As we discussed earlier, in a block mode simulation the block propagates through each element
only once by default.
This is controlled by the “number of output signals” property which has a default value
For simulations with feedback loops we can select how many blocks are generated by each
element source by setting the value of the “number of output signals” property.