SMatrix¶

class photonforge.SMatrix(frequencies, elements, ports=None)¶

S matrix object.

Parameters:

frequencies – Frequency values for the computed elements.
elements – Mapping from pairs of port names and mode numbers to S matrix elements. The keys have the format: ("in_port@in_mode", "out_port@out_mode").
ports – Mapping from port names to ports or to None.

Example

>>> s_matrix = SMatrix(
...     [C_0 / 1.55],
...     {("P0@0", "P0@0"): [0], ("P0@0", "P1@0"): [1j]},
... )

Methods

`apply_time_delay`(delay)	Apply a time delay to the S matrix data.
`copy`()	Create a copy of this s_matrix.
`estimate_delays`([lossless])	Estimate delays from the phase data of the provided S matrix.
`estimate_phase`()	Create a new S matrix object with the same amplitude data as the current S matrix.
`load_snp`(cls, filename[, ports])	Load an S matrix from a Touchstone (snp) file.
`write_snp`(filename)	Write this S matrix in a Touchstone (snp) file.

Attributes

`elements`	S matrix elements (read only).
`frequencies`	S matrix frequencies (read only).
`ports`	S matrix ports (read only).
`wavelengths`	S matrix wavelengths (read only).

apply_time_delay(delay)¶

Apply a time delay to the S matrix data. Multiplies the S matrix by $e^{2 pi i f d}$ where $f$ is the frequency and $d$ is the time delay. The S matrix is modified in-place.

Parameters:: delay – The time-delay to be applied, in seconds.
Returns:: This object.

copy()¶

Create a copy of this s_matrix.

Returns:: New copy.

elements¶: S matrix elements (read only).

estimate_delays(lossless=False)¶

Estimate delays from the phase data of the provided S matrix.

Parameters:: lossless – If False, estimates the actual delays; if True, estimates the lossless delays. The lossless delays are less than the true delays, and they give the phase difference between the provided phase data and that of a minimum-phase-shift system with the same amplitude data. The lossless delays may be more appropriate for pole-residue fitting.
Returns:: Dictonary of estimated delays, one per matrix element.

estimate_phase()¶

Create a new S matrix object with the same amplitude data as the current S matrix. The phase data in the new S matrix is estimated from the amplitude data assuming a minimum-phase-shift (mps) model. The phase at zero frequency is preserved.

Returns:: Resulting minimum-phase-shift S matrix.

frequencies¶: S matrix frequencies (read only).

static load_snp(cls, filename, ports=())¶

Load an S matrix from a Touchstone (snp) file.

Parameters:

filename – Touchstone file name to load.
ports – Sequence of port names to be associated with the ports in the Touchstone file. Each element in the sequence can also be a tuple with port name and number of supported modes in case of multimode ports. If no ports are provided, default ones are used.

Returns:

SMatrix.