Enum StepRule 

#[non_exhaustive]
pub enum StepRule {
    Fixed(f64),
    NonlinearPhase(f64),
    Logarithmic(usize),
    Fwm {
        phase_rad: f64,
        bandwidth_hz: Option<f64>,
        update: StepUpdate,
        max_nl_phase_rad: Option<f64>,
    },
}

The step size of ManakovSplitStep.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Fixed(f64)

Steps of a fixed length (km); the last step of a span is shortened.

NonlinearPhase(f64)

Steps whose largest nonlinear phase $\max_{t} \phi(t)$ is this rotation (rad).

Logarithmic(usize)

This number of steps over every propagated length (a span), distributed logarithmically (logarithmic_steps, Bosco et al. 2000, eq. (6)): every step carries the same integrated power, short where the power is high. Without loss, equal steps.

Fwm

The four-wave-mixing-aware rule of Musetti, Serena and Bononi (2018): the first step of every span bounds the phase mismatch of the four-wave mixing across the signal bandwidth $B$ (eq. (13)),

$$ h_{1} = \frac{\Phi_{\mathrm{FWM}}}{|\beta_{2}| (2\pi B)^{2}}, $$

and the next steps grow with the attenuation by update. The rule does not depend on the power: the error it leaves on the SNR is fixed by $\Phi_{\mathrm{FWM}}$ (about 0.01 dB for 20 rad with the constant local error, 4 rad with the nonlinear-phase update, Sec. IV-B).

Fields

phase_rad: f64

$\Phi_{\mathrm{FWM}}$ (rad).

bandwidth_hz: Option<f64>

$B$ (Hz): the bandwidth of the signal; None measures it on the fields at the start of the propagation (signal_bandwidth).

update: StepUpdate

The growth of the steps along a span.

max_nl_phase_rad: Option<f64>

Also bound the largest nonlinear phase of a step to this rotation (rad), the rule of StepRule::NonlinearPhase: the four-wave-mixing rule alone lets the steps of a single channel exceed its dispersion length at high power.

Implementations

impl StepRule

pub const FWM_DEFAULT: StepRule

The default rule: Musetti et al. for an SNR error of about 0.01 dB in WDM ($\Phi_{\mathrm{FWM}}$ = 20 rad, the constant local error, the bandwidth measured on the fields), and at most 0.02 rad of nonlinear phase per step, which a single channel at high power needs: one DP-16QAM channel of 32 GBd over 10 × 80 km at 2 to 8 dBm gets 0.3 to 0.7 dB too much SNR with the four-wave-mixing rule alone, the converged values with both (validation/cards/musetti2018_fig7.yaml).

Trait Implementations

impl Clone for StepRule

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for StepRule

impl Debug for StepRule

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for StepRule

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for StepRule