pypho v3

pypho_fiber

The fiber class models the transmission of an optical signal along a fiber.

For this the non linear Schrödinger equation is solved numerically by the Fourier-Split-Step-Method:

$$\frac{\partial A_x }{\partial z} + \beta_{1x} \frac{\partial A_x }{\partial t} + \frac{j\beta_{2} }{2} \frac{\partial A_x }{\partial t^2} -\frac{\beta_{3} }{6} \frac{\partial A_x }{\partial t^3} + \frac{\alpha }{2}A_x = i\gamma\left( |A_x|^2 + \frac{2}{3}|A_y|^2 \right)A_x$$ $$\frac{\partial A_y }{\partial z} + \beta_{1y} \frac{\partial A_y }{\partial t} + \frac{j\beta_{2} }{2} \frac{\partial A_y}{\partial t^2} - \frac{\beta_{3} }{6} \frac{\partial A_y }{\partial t^3} + \frac{\alpha }{2}A_y = i\gamma\left( |A_y|^2 + \frac{2}{3}|A_x|^2 \right)A_y$$

Both polarisations and their interaction are calulated. You cannot "switch" one polarisation off, to reduce the calculation time.

 

pypho_fiber.__init__(glova, fibertype, D, S, gamma, alpha, l, birefarray, phi_max)

Instantiation and parameter setting.

Parameter	Type	Description
glova	instance	Global parameters
fibertype	string	Sets default values for typical fiber types: 'SSMF': D=17, S=17, alpha=0.2
D	float	Dispersion coefficient at the center frequency pypho_setup.f0 in $\frac{\text{ps}}{\text{nm km}}$.
S	float	Dispersion slope coefficient in $\frac{\text{ps}}{\text{nm}^{2} \text{km}}$.
gamma	float	Nonlinear coefficient $\gamma$ in $\frac{1}{\text{W km}}$.
alpha	float	Fiber attenuation $\alpha$ in $\frac{\text{dB}}{\text{km}}$.
l	float	Fiber length in km.
birefarray	list	This list describes the polarisation properties of the fiber. The list must include a rotation angle birefarray[].angle the fiberlength birefarray[].z_point and a $\Delta\beta_1 = \beta_{1x} - \beta_{1y}$ value birefarray[].delta_beta valid to the next of the birefarray[].z_point.

 

Output	Type	Description
User defined variable	pypho_fiber.pypho_fiber

 

pypho_fiber.__call__(E, fibertype (optional), D (optional), S (optional), ...
...gamma (optional), alpha (optional), l (optional), ...
...birefarray (optional), phi_max (optional))

Parameter	Type	Description
E	list	List in which the optical data and noise signal are defined. Read here about data signal and noise representation
Optional paramter		As defined above

 

Output	Type	Description
User defined variable	list	Returns a list in which the optical data and noise signal are defined. Read here about data signal and noise representation.