1. Jose Luis Sirvent Jonathan Emery Student Meeting 12– February -2012

2.  Loss of -3dB: ◦ Horizontal plane: Disk-Fiber +-0.25mm ◦ Vertical plane: Fiber-Fiber misalignment 60um ◦ Angular tolerance: 0.5 deg ◦ Signal received ~ 0.37%

3.  Signal appearance ◦ 30Khz ◦ 0.0422 mWpp

4.  Loss of -3dB: ◦ Horizontal plane: Disk-Fiber +- 0.3mm ◦ Vertical plane: Width of the slides ◦ Angular tolerance ~ +-2.5 deg ◦ Signal received ~ 0.58%

5.  3.1 Focuser with commercial components

6.  Loss of -3dB: ◦ Horizontal plane: Fiber-Lens 7mm -+ 250um ◦ Horizontal plane: Lens-Disk 2.23mm -+60um (Too small?) ◦ Vertical plane: Slits width ◦ Angular tolerance ~ +-2deg ◦ Signal received ~ 11% (Improvement > Factor 10!!)

7.  Improvement of tolerances: ◦ Defocus  Bigger spot size ◦ Horizontal Plane: Fiber - Lens 4.29mm +- ? ◦ Horizontal Plane: Lens – Disk 4.35mm +- 200um ◦ Vertical plane ~ +-2deg ◦ Signal received ~ 11% 4.35 -+ 0.2 mm

8.  Fit with sinusoid

10. Transmission (50mVpp)Reflection (80mVpp) Focuser 800mVpp

11. LASER DIODES Reception Expected dBm CompanyComponentClassMax Curr.Max Power (dBm)Max Power (mW)StabilityCommentsTransRefFocusCol OPTEKOPF372AGaAIAs LED100mA-100.1StableFine, Low Power-34.33-32.35-19.55- KYOSEMIKLD085VCVCSEC12mA1.591.44Stable -22.74-20.76-7.96 - LASER COMPPL85B002ST83-T-0 45mA6.985NoisyNoisy (Reflections)-17.35-15.37-2.57 - Last weeks PHOTODIODES CompanyComponentClassSensibility (dBm)Sensibility (mW)Saturation (dBm)Saturation (mW)Comment KYOSEMIKPGX1GGaAs PD-TIA-243.98E-03-- High-Pass filter F> 1Mhz KYOSEMIKPIX150M-H33Si PD-TIA-317.94E-04-- KYOSEMIKPIXAIG-T-STSi APD-TIA-335.01E-04-- OPTEKOPF562ASi PD-417.94E-05-70.200 LASER COMPPDSIU500ST83-W-0Si PD-21.96.46E-0331.995TIA Circ OK but F<2Mhz

12. Kyosemi Laser Components

14.  Disk D=14cm  8796 slots of 50um ◦ Actual accuracy: 710 uRad. ◦ Specifications: 25 uRad. ◦ Needed Improvement of factor 30.  How to reach specifications (Interpolation): ◦ 1.Offline Processing (Software requirements) ◦ 2.Online Processing (Possible by hardware)

15.  Disk D=14cm  8796 slots of 50um ◦ Actual accuracy: 710 uRad. ◦ Specifications: 25 uRad. ◦ Needed Improvement of factor 30.  How to reach specifications (Interpolation): ◦ 1.Offline Processing (Software requirements) ◦ 2.Online Processing (Possible by hardware)

16.  2.Online Processing  1. Interpolation with previous cycle reference  Source of errors: Bad measurement in previous cycle = interpolations errors in next.  Allways there will be a delay of 0.5 cycle.  Possible improvement: Histeresys when crosing zero.

17.  2.Online Processing  2. Interpolation of Sin-Cos Encoders:  Two fibers if working with Focuser (displaced 90deg)  No errors or delay: Relationship between signals  Variations in speed applied immediately.  Interpolation Unit + Quadrature decoder