# Core IFO Model

The core IFO model will be a simulation model which describes the interferometric part of LCGT. Calculating the behavior of the electric fields inside the interferometer is the main task of this model. This model will also simulate radiation pressure forces from the electric fields to the mirrors in order to provide an interface with the mechanical system.

## Analytical models

### Design sensitivity in 2005

- Author: Masaki Ando
- Platform: Matlab

Default design in 2007(BRSE). This model was designed for TAC meeting held at 2005/5/23.

### Noise Calculation

- Author: Kentaro Somiya
- Platform: Mathematica

You need to run the classical-noise code first so that it saves the equation in your My Document folder. Actually with this code alone, you can calculate the observational range and the spectrum with given parameters.

The BNS code exports the classical-noise equation and gives the optimal finesse and detune phase. Note that the SRM reflectivity is fixed in each BNS code. You need to copy this example file for rho088, rho090, etc. and change rho and the file names in the new codes. In each code, after you run it once, go back to 3.2.3 and change the number in Range"xx" so that it gives you True instead of False. This tells you the right ITM power transmittance T. Then you need to use this right T in 3.2.5 (manually). Then run the rest of the code so that it gives you the spectrum. The tendency of the SN against different T is saved in My Document as well. Running each rhoxx codes, you will get the contour plot of different rhos and Ts.

The BBH code does the same thing, besides this code chooses the optimal power while it is fixed to 75W in the BNS code (as a matter of fact, this BBH code is better written because I made this later).

For both BNS and BBH codes, the DC readout phase is fixed to 80 degrees. This is because when I checked the tendency in 2003, it is always the phase close to 90 deg that makes the SN highest for the binaries and because indeed 90 deg is not good in terms of laser noise problems, which is shown in my paper in 2006.

## Simulation models

### FINESSE model for LCGT

- Author: Fumiko Kawazoe
- Descripton: Frequency domain simulation
- Platform: FINESSE

This model investigates a primitive (i.e. loss less, symmetric) LCGT disign for Sato method which has all reflective 60MHz AM sidebands and all transmissive 10MHz PM sidebands. Note that some of parameters in this model are not matched to Masaki's analytical model above.

### Loopnoise for LCGT

20090702_loopnoise255c_LCGT_Sato_model.zip

- This version is designed to investigate Sato, Kokeyama, Kawazoe model discussed in 2004-2007 for loss less and symmetric case.

20090831_loopnoise274_LCGT2009_new2.zip

- This version includes results of the interferometer bandwidth meetings held between May to September 2009.
- Author: Osamu Miyakawa
- Descripton: Frequency domain simulation
- Platform: Matlab

This is a set of scripts to calculate the loop noise for LCGT parameters running on Matlab using Optickle engines which was developed by Matt Evans in LIGO group. It produces many usuful plots to compare LCGT optical configurations conveniently. Radiation pressure effects are implemented in all optical gain matrix, and the carrier vacuum are available form dark port, laser, pox, poy and attenuators (but the RF vacuum is not yet.). See attached readme.txt for more detail.

### e2e model for AdLIGO single arm cavity

20060710_e2e_AdLIGO_arm_cavity.zip (138MB)

- Author: Osamu Miyakawa
- Descripton: Time domain simulation
- Platform: JAVA, C++

This package includes time domain simulation codes for varies conditions of single arm cavity of Advanced LIGO running on the e2e developed in LIGO group. Some of the results are shown here in the discussion of SPI subgroup. You can start with '01_max_input_power' folder as the first trial which produces figures shown in the presentation file above at page 10. This code should be replaced for LCGT version as soon as possible. A new LCGT suspension model is needed to perform calculations on the e2e.