Differences between revisions 25 and 34 (spanning 9 versions)

Optical Levers

Related subgroups: VIS, IOO, MIF, VAC, CRY...

back to AOS top

Contents

Optical Levers

Scope

The scope of optical levers is to sense local angular motions (pitch and yaw) of any mirrors supported by vibration isolation system and other suspended stuffs including suspeded optical benches.

Applicable Documents

TBD; just see the links below.

General Description

Naming Conventions

Locations

BS chamber
ITM chambers (X,Y)
ETM chambers (X,Y)
PRC chambers (PRC, PR2, PR3)
SRC chambers (SRC, SR2, SR3)
MC chambers (MC1, MC2...)

Requirements

Sensor noise should be less than xxx.
Sensor's dynamic range should be greater than xxx.
At least horizontal degrees of freedom (X,Y)
Preferably a vertical sensor (Z) and side
The sensors have to be rigidly mounted on the ground so that these are useful for remembering the position of the mirror and recording the drifts.

Characteristics

Each optical lever consists of an optical system, a frontend circuit, and a human interface software.
The optical system consists of the following parts: a light source, optical fibers, a focusing telescope, viewport windows, a detector, and pylons which support the focusing telescope and the detector.

The frontend circuit is TBD. Maybe we need analog cables (and what kind of connector should we use?), whitening filters and antialiasing filters. Maybe the matrix circuit will be realized using the digital systems, but in commissioning phase, we will need analog matrix.

The human interface software is TBD, which shows the mirrors' dofs monitored by Optical Levers.

Light source

For the light source, proposed candidates are
- superluminous LED (SLED) or
- laser light source as LIGO.

Optical Fibers

The optical fibers transmit the light from the source to the focusing telescope.

Focusing Telescopes

TBD. Moving linear stage with micrometer and some optical components like collimators?

Viewport windows

See also the viewport subsystem.
It should be transparent for the light source wavelength.
There should be no wedge; otherwise the multiple spots of light would be problematic.
See JGW-T1201231, Effect due to viewports for optical lever (in Japanese)

Detectors

The detector will be an ordinary quadruplet photocondutive circuit with QPD. The noise level at xxx Hz should be xxx m/Hz²

Pylons

The pylons must be designed.

-  ⇤ ← Revision 25 as of 2011-10-07 18:49:58 → 
  Size: 3836
  Editor: TomotadaAkutsu
  Comment:
+   ← Revision 34 as of 2012-09-16 20:42:10 → ⇥
  Size: 4018
  Editor: KiwamuIzumi
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
 Line 1:
-= Optical Lever (Room Temperature) =
+= Optical Levers =
 Line 4:
-'''[[../|..Up]]'''
+'''[[KAGRA/Subgroups/AOS| back to AOS top]]'''
 Line 8:
-Sensing local motions including --(longitudinal dof and)--
all alignment dofs (pitch, yaw and roll) of any mirrors supported by vibration isolation system.

<!> Note on the operating temperature: here the system is assumed to be utilized at room temperature, not in cryogenic temperature.
+ . The scope of optical levers is to sense local angular motions (pitch and yaw) of any mirrors supported by vibration isolation system and other suspended stuffs including suspeded optical benches.
-Line 15:
+Line 11:
-TBD; just see the links below.
+ . TBD; just see the links below.
-Line 20:
+Line 16:
-TBD
+ . TBD
-Line 38:
+Line 34:
-Each optical lever consists of an optical system, a frontend circuit, and a human interface software.
The optical system consists of the following parts: a light source, optical fibers, a focusing telescope, viewport windows, a detector, and pylons which support the focusing telescope and the detector.
+ . Each optical lever consists of an optical system, a frontend circuit, and a human interface software.
 . The optical system consists of the following parts: a light source, optical fibers, a focusing telescope, viewport windows, a detector, and pylons which support the focusing telescope and the detector.
-Line 41:
+Line 37:
-whitening filters and antialiasing filters.
Maybe the matrix circuit will be realized using the digital systems, but in commissioning phase,
we will need analog matrix.
The human interface software is TBD, which shows the mirrors' dofs monitored by Optical Levers.
+whitening filters and antialiasing filters. Maybe the matrix circuit will be realized using the digital systems, but in commissioning phase, we will need analog matrix.
 . The human interface software is TBD, which shows the mirrors' dofs monitored by Optical Levers.
-Line 47:
+Line 41:
-For the light source, proposed candidates are
 * superluminous LED (SLED) or
 * laser light source as LIGO.
+ . For the light source, proposed candidates are
  * superluminous LED (SLED) or
  * laser light source as LIGO.
-Line 52:
+Line 46:
-The optical fibers transmit the light from the source to the focusing telescope.
+ . The optical fibers transmit the light from the source to the focusing telescope.
-Line 55:
+Line 49:
-TBD. Moving linear stage with micrometer and some optical components like collimators?
+ . TBD. Moving linear stage with micrometer and some optical components like collimators?
-Line 58:
+Line 52:
-See also the [[../Viewport1|viewport subsystem]].
It should be transparent for the light source wavelength.
The wedge should be avoided; otherwise the multiple spots of light would be problematic.
+ . See also the [[../Viewport1|viewport subsystem]].
 . It should be transparent for the light source wavelength.
 . There should be no wedge; otherwise the multiple spots of light would be problematic.

 . See [[http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=1231|JGW-T1201231, Effect due to viewports for optical lever (in Japanese)]]
-Line 63:
+Line 59:
-The detector will be an ordinary quadruplet photocondutive circuit with QPD.
+ . The detector will be an ordinary quadruplet photocondutive circuit with QPD. The noise level at '''xxx''' Hz should be '''xxx''' m/Hz^2^
-Line 65:
+Line 61:
-=== Pyrons ===
The pyrons must be designed.
+=== Pylons ===
 . The pylons must be designed.
-Line 69:
+Line 65:
-TBD
+ . TBD
-Line 72:
+Line 68:
-TBD
+ . TBD
-Line 77:
+Line 73:
-<!> Some of the LIGO documents listed below are '''NOT''' public; to access them, you may need your own LSC account.
+ . <!> Some of the LIGO documents listed below are '''NOT''' public; to access them, you may need your own LSC account.