===== Clocklaser =====

<note important> Put a **paper infront R1 and R2**, when beam adjustment! Too high input power can damage the mirrors of the resonator!</note>

==== Typical values and datasheets of the clocklaser system ====
=== Laserdiode (ECDL) ===
  * {{ :groups:mg:private:resonatoren:clocklaser:ds_eyp-rwe-0940-08000-0750-sot01-0000.pdf |Datasheet }}
  * {{ :groups:mg:201705051620.pdf |Testsheet [Serial Number: BA-02465]}}
  * {{ :groups:mg:201705051619.pdf |Testsheet [Serial Number: BA-02464]}}


  * Temperature Laserdiode (marking 1): 
    * act: 24,4°C [Sep, 2019]
    * set: 24,4°C [Sep, 2019]
    * min-max: 15°C - 35,1°C [Sep, 2019]
    * act: 24,5°C [2018]
  * Typical Current Laserdiode (marking 1):
    * act: 98 mA  [Sep, 2019]
    * set: 97/98 mA  [Sep, 2019]
    * act: 96 mA [2018]

=== Tapered Amplifier (TA) ===
  * Typ: EYP-TPA-0915-01500
  * Datasheet: {{ :groups:mg:private:resonatoren:clocklaser:eyp-tpa-0915-01500-3006-cmt03-0000.pdf |EYP-TPA-0915-01500}}

<note important>Light with input power of min **10mW** must pass TA! Maximum current is **3A**. Otherwise the TA will be broken</note>

  * Temperature TA (marking 2): 
    * act: 20°C [Sep, 2019]
    * set: 20,1°C [Sep, 2019]
    * min-max: 15 - 35,1°C [Sep, 2019]
    * act: 20°C [2018]
  * Typical Current TA (marking 2):
    * act: 1364/ 1453 mA [Sep, 2019] <color #ff0000>wieso zwei verschiedene Werte?</color> <color #9acd32>Beim Einschalten PID wird Strom größer</color>
    * act: 1201 mA [Nov, 2019 nach Einstellen l/2, um mehr Leistung an Leistungsstab. zur Verfügung zu stellen ] 
    * set: 1464 mA [Sep, 2019] 
    * max < 1,5 A 
    * act: 1176 mA [2018]

==== Turning on and off the clocklaser system ====
=== Turning on the laser ===
We use toptica electronics:
  - Turning the main-key to on. The LED´s from the temperature control will go on!
  - Push the green button. The green LED from the button will go on!
  - Switch on the toggle (=Kippschalter) of the laserdiode controller. The green LED of the laserdiode controller will go on!
  - Switch on the toggle of the TA, if he is seeded! The green LED of the TA controller will go on!

Note: If the switches are on, then not steps 3. & 4.

=== Turning off the laser ===
Note: Both toggles to switch off the laserdiode and TA are not required! 
  - Push the red button. The green LED will go out!
  - Turning the main-key to "mains"

=== Only turning off the laserdiode ===
  - Switch off the toggle from the TA. The green LED from the TA module will go out!
  - Switch off the toggle from the laserdiode. The green LED from the laserdiode module will go out!

=== Only turning off the TA ===
  - Switch off or on the toggle from the TA. The green LED from the TA module will go out!


====== Fast Locking of R1 ====== 
  - Check laser frequency with wavemeter:<color #ff0000>  XXX </color>
  - Check laser power @ upstairs PD: Display should shown stop position
  - Check modes of scan cavity: Has to be single mode
Note: If cases 1, 2 and 3 are given, then lock the laser like:
  - <color #ff0000>XXX Das darfst du schreiben mit welchen Knopf wann gedrückt wird</color>
  - <color #ff0000>XXX</color>
  - <color #ff0000>XXX</color>

==== Errors ====
**A)** To less power @ upstairs PD\\
**B)** To less power @ scan cavity\\
**C)** Acoustic Signal of TA controller\\

Solution of **A**, **B** and **C**: In most cases it is sufficient to increase incouple power of TA\\
<note important>Necessary lock power: ~200mW <color #ff0000>An welcher Stelle?</color></note>
  - turn off the TA lock:
      - turn off the I and P switch
      - Note: D is always off
  - <color #ff0000>Adjust the incoupling power in the TA with mirror XYZ in vertical direction until Errors A and B are fixed
</color>
  - Lock of TA 
      - If the incoupling is good -> ∼1A - after TA (Pos.C): ~200mW


====== Power up the clocklaser system ======  

=== Laser ===
  - Check power of Laserdiode direct after laser housing (Pos.A)
  - TA Lock 
    - first Check: 
      - //Info: necessary lock power: 200mW// 
      - If the incoupling is good -> ∼1A - after TA (Pos.C): ~200mW
      - fast acoustic Signal means the powerstabilisation warning (lock power too low <color #ff0000>gibt es noch andere Gründe?</color>)
{{ :groups:mg:private:resonatoren:clocklaser:error_1.jpeg?200|}}
    - If the incoupling is bad (frequent cause of powerstabilisation warning/ show "error 1"): 
      - P-Stab. off (PID) & block the beam!
      - adjust mirror MTA (horizontal beam way); references are the peaks (CH4) of Single-Mode-Signal (show "ideal situation")
      - Test and switch on the P-stab. (beam is blocked!): warn signal on? 
      - if the acoustic signal is off > measure the incoupling power (Pos.E) max. ~120müW 
      - Lock the Resonator  
{{:groups:mg:private:resonatoren:clocklaser:20190924_133125.jpg?200|}}
{{:groups:mg:private:resonatoren:clocklaser:ideal_situation.jpeg?100|}}


=== R1 ===
  - Modelocking of R1
    - Tune the Piezo upto TEM00 is observable
    - if necessary use Mode-Reset
  - Intensity Lock of R1
    - after Isolator (ISO3) direct infront R1 (Pos.E): max. ~120müW / min. ~100müW
      - otherwise improve the optical way to the Isolator for more power
    - mit Output Offset des Intenstitäts-PID auf 100müW herunterdrehen
  - ** HENCE:** Check **always** Power after Isolator of R1: **not more than 100müW!!!**
  - **Only aktivate PDH/TA-Lock + couple into R1, if the power is 100(±20)müW after the Isolator of R1**
  - Modelocking of R1 (Step 1)
  - Lock RAM
  - Lock Fiberstabilization

===== Littmann design =====
{{:groups:mg:img_0260.jpg?300|}}
{{:groups:mg:private:resonatoren:clocklaser:measurement_points_ecdl_r2.png?300|}}
{{:groups:mg:private:resonatoren:clocklaser:measurement_points_in_front_of_r2.png?200|}}

**Typical efficiencies at 916 nm:**
  * Isolators: 80 %
  * AOMs: 50-60 %
  * Fiber coupling: 50 % 

**Typical values for the laser:**
  * Frequency: 327.5293 THz (doubled upstairs directly behind SHG: 655.058 566 THz)
  * Frequency: 327.5294 THz [Sep, 2019]
  * Power after ECDL (Pos.A):
    * ~11,2 mW (@~97/98 mA) [Sep, 2019]
    * ~12 mW (@ ~90 mA) [2016]
    * ~<color #ff0000>XX</color> mW (@ ~96 mA) [2016]
  * Power front of TA (Pos.B): 
    * ~ 9 mW [Sep, 2019]
  * Power after TA (Pos.C): 
    * ~290 mW (@~1364 mA) [Sep, 2019]
    * ~<color #ff0000>XX</color> mW (@ ~1165 mA) [2018]    
    * ~200 mW (@ ~1000 mA) [2016]
  * Power after TA (Pos.D): 
    * ~ 230 mW (@~1364 mA) [Sep, 2019]
  * Power in front of ISO3
    * ~ 135müW (@~1364 mA TA) [Sep, 2019]
  * Power in front of ISO3
    * ~ 120müW (@~1364 mA TA) [Sep, 2019]
TA current should be <1.2A <color #ff0000>noch richtig, wenn jetzt 1,4A?</color> otherwise the fiber stabilization will soar (=aufschwingen)

**Typical values in front fibers:**
  * Power before fiber for wavemeter/comb/mode analysis cavity:
    * ~12 mW [2016]
    * ~<color #ff0000>XX</color> mW [2018]
  * Power before AtomLabFiber: 
    * ~30 mW -> 15 mW upstairs before TA [2016- without fiber stabilization]
    * ~<color #ff0000>XX</color> mW -> 20 mW upstairs before TA [2018]
  * Power to R2: 
    * ~2.5 mW [2016]
    * ~<color #ff0000>XX</color> mW [2018]

**Typical values after fibers:**
  * Power before fiber for 
    * Comb:
      * ~<color #ff0000>XX</color> mW [2018]
    * Wavemeter:
      * ~<color #ff0000>XX</color> mW [2018]
    * Scan cavity:
      * ~<color #ff0000>XX</color> mW [2018]
  * Power after AtomLabFiber: 
    * 20 mW upstairs before TA [2018]
  * Power after R2 fiber: 
    * ~<color #ff0000>XX</color> mW [2018]

**Typical values for the resonators:**
  * In front of telescope: 2.2 mW
  * In front of AOM: 1.5 mW
  * In front of fiber: 450 µW
  * 100 µW between Isolator and BS
  * 50 µW in front of Resonator

**Typical values for locking signals:**
  * PDH error signal locked ~500 mV PP / unlocked ~200 mV PP
  * Intensity Error signal ~2 mV PP / DC: 
  * Fiber Stabilization Locked ~200 mV PP / Unlocked ~2 Volt PP


**Manuals and Datasheets**