# Virgo model

Interferometer for Finesse 3. Can be used with the
[finesse-virgo](https://gitlab.com/ifosim/finesse/finesse-virgo)
package.

Katscript files are organized by priority number (first two number),
which indicate the file loading order, the lowest at first.

## Sections

Katscript files are organized in different types, which are `values`,
`optical setup`, `link`, `cavities definition`, `degree of freedom`,
`detectors` and `after variables`.

### values

priority number from 00 to 09

Contains values used in the setup

### optical setup

priority number from 10 to 19

Defined part of the optical setup (Laser, Mirror, etc.)

### link

priority number from 20 to 49

Link together parts of the optical setup defined before

### cavities

priority number from 50 to 69

Defines Finesse 3 cavity

### degree of freedom

priority number from 70 to 89

Defines Finesse 3 degree of freedom

### detectors

priority number from 70 to 89

Add Finesse 3 readout

### after variables

priority number from 90 to 99

Defines variable which depends of components in the setup for
preprocessing (finesse-virgo package for example)

## Getting started

Code example to build a Virgo model with these scripts.

```py
    virgo = Virgo(
        files_to_parse = [
            "00_variables.kat",
            "01_arm_north.kat",
            "01_arm_west.kat",
            "01_detection.kat",
            "01_laser_and_modulator.kat",
            "01_recycling_cavity.kat",
            "02_B5_path.kat",
            "05_attenuator.kat",
            "05_link_length.kat",
            "05_modulation.kat",
            "05_tuning.kat",
            "10_laser_and_modulator.kat",
            "10_faraday_isolator.kat",
            "10_recycling_cavity.kat",
            "10_arm_north.kat",
            "10_arm_west.kat",
            "10_detection.kat",
            "10_B2_attenuator.kat",
            "10_B4_attenuator.kat",
            "25_link_laser_and_modulator_faraday_isolator_noSIB1.kat",
            "20_link_faraday_isolator_recycling_cavity.kat",
            "25_link_faraday_isolator_B2_attenuator_noSIB2.kat",
            "20_link_recycling_cavity_arms.kat",
            "25_link_recycling_cavity_detection_noSDB1.kat",
            "25_link_recycling_cavity_B4_attenuator_noSPRB.kat",
            "30_link_arm_north_SNEB.kat",
            "50_cavities.kat",
            "70_detectors.kat",
            "70_degree_of_freedom.kat",
            "99_after_variables.kat",
        ],
    )
```

The advantage of this is the control we have over the interferometer
 simulation, and the readibility. Tracking change is also easier,
variable definition being detached from setup configuration.