Optics

Common optical building blocks are provided for building up an optical system. Some have more detailed pages which are listed in the table of contents below.

• Mirror
• Beamsplitter

Directional Beamsplitter

directional_beamsplitter
dbs
DirectionalBeamsplitter

Represents a directional beamsplitter optical component. Connections made between ports:

• port 1 to port 3 * port 3 to port 4 * port 4 to port 2 * port 2 to port 1

Syntax

dbs name 

Required

name: Name of newly created directional beamsplitter.

Isolator

isolator
isol
Isolator

Represents an isolator optical component with a suppression factor. Suppresses the light field transmitted from p2 to p1. The field from p1 to p2 is.

Syntax

isol name S=0.0

Required

name: Name of newly created isolator.

S: Power suppression in dB. Defaults to 0

Parameters

Name	Description	Units	Data type	Can change during simualation
S	Power suppression	None	float	✓

Lens

lens
Lens

Represents a thin lens optical component with an associated focal length.

Syntax

lens name f=inf

Required

name: Name of newly created lens.

Optional

f: Focal length of the lens in metres; defaults to infinity.

Parameters

Name	Description	Units	Data type	Can change during simualation
f	Focal length	m	float	✓

Modulator

modulator
mod
Modulator

Represents a modulator optical component with associated properties such as modulation frequency, index and order.

Syntax

mod name f midx order=1 mod_type=pm phase=0.0 positive_only=false

Required

name: Name of newly created modulator.

midx: Modulation index, >= 0.

Optional

f: Frequency of the modulation (in Hz) or Frequency object.

order: Maximum order of modulations to produce. Must be 1 for amplitude modulation. Defaults to 1.

mod_type: Modulation type, either ‘am’ (amplitude modulation) or ‘pm’ (phase modulation). Defaults to ‘pm’.

phase: Relative phase of modulation (in degrees). Defaults to 0.0.

positive_only: If True, only produce positive-frequency sidebands. Defaults to False.

Parameters

Name	Description	Units	Data type	Can change during simualation
f	Frequency	Hz	float	✓
midx	Modulation index	None	float	✓
phase	Phase	degrees	float	✓
order	Maximum modulation order	None	int	✗
mod_type	Modulation type ('am', 'pm')	None	int	✗
positive_only	Positive only	None	bool	✗

Optical Bandpass

optical_bandpass
obp
OpticalBandpassFilter

An idealised optical bandpass filter that will transmit an optical frequency around some central frequency with a 3dB bandwidth.

Syntax

obp name fc=0 bandwidth=1000 filter_hom=none

Required

name: Name of element

fc: Central frequency

bandwidth: Filter 3dB bandwidth

Optional

filter_hom: Individual higher order modes can be filtered and transmitted by setting this to a tuple of (n, m). If None then no mode filtering is done. This cannot be changed during a simulation.

Parameters

Name	Description	Units	Data type	Can change during simualation
fc	Central frequency	Hz	float	✓
bandwidth	Bandpass bandwidth	Hz	float	✓

Frequency Loss

floss
FrequencyLoss

Represents an unphysical element which introduces a loss and/or phase for a particular frequency.

Syntax

floss name f loss=0 phase=0

Required

name: Name of newly created lens.

Optional

f: Frequency to apply loss and phase to.

loss: Fractional loss at the frequency

phase: Phase change at the frequency

Parameters

Name	Description	Units	Data type	Can change during simualation
loss	Loss	None	float	✓
phase	Phase	Degrees	float	✓
f	Frequency	Hz	float	✓