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Oscillator stability & ASE Reduction Xiangyu Zhou 20. Nov. 2015.
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Transcript of Oscillator stability & ASE Reduction Xiangyu Zhou 20. Nov. 2015.
Oscillator stability & ASE Reduction
Xiangyu Zhou
20. Nov. 2015
Layout
Upgrade laser system, undergroundYb-doped fiber & Thin-disk Yb:YAG @ 1030 nm
New laser system, on the groundYb-doped fiber & Rod Nd:YAG @ 1064 nmYb-doped fiber & Thin-disk Yb:YAG @ 1030 nm
Old underground laser systemYb-doped fiber oscillator with
Transmission grating
Yb-doped fiber pre amplifier
Yb-doped fiber main amplifier
Pulse picker
Yb:YAG thin-disk regenerative amplifier
Yb:YAG thin-disk multipass amplifier
SHG
Synchronization system
SHGRF GUN
51.9 MHz
2, 5, 25, 50 HzSingle or Double bunch
0.2 nJ @ 1037 nm
Yb-doped fiber main amplifier
Transmission grating pair
stretcher
2856 MHz triggerFrom Accelerator
Yb-doped fiber pre amplifier
>μJ @ 1037 nm
New underground laser systemYb-doped fiber oscillator with
Transmission grating
Yb-doped fiber pre amplifier
Yb-doped fiber main amplifier
Pulse picker
Yb:YAG thin-disk multi-pass cavity amplifier
Yb:YAG thin-disk multipass amplifier ×3
SHG
Synchronization system
SHGRF GUN
51.9 MHz
2, 5, 25, 50 HzSingle or Double bunch
0.2 nJ @ 1037 nm
Yb-doped fiber main amplifier
Transmission grating pair
stretcher
2856 MHz triggerFrom Accelerator
Yb-doped fiber pre amplifier
>μJ @ 1037 nm
Pulse picker
10 MHz
Fiber pre-amplifier
LD Pump
SMF
WDMcoupler
WDMcoupler
700 mW @ 976 nm
Yb-doped fiber
WDMcoupler
Splitter Coupler
Splitter Coupler
50%50%
70%30%
50%35%15%
• Reduce the ASE• Increase the amp efficiency• All the fibers are coupled
The issue in pulse picker
INTENSITY MODULATOR : NIR-MX-LN-10
51.98 MHz10 MHz
51.98 MHz
Double bunch
96 ns
E.O. voltage
Semiconductor Optics amplifier (SOA) Pulse Picker
SOA input signal generation
Discriminator Gate generator 1 Gate generator 3 Level adapter
Gate generator 2Reference signal10MHz
Semiconducter Optics amplifier (SOA) Pulse Picker
Cut & Soldering
SOA-1020-110-HI-27dB (Innolume)SOA chip mount
Input: 3 mWOutput: 3 mW52 MHz 10.38 MHz
Oscillator output
Spectrum Pulse train
* Broadband and Stable
Output power8.2mW
* Repetition frequency : 51.9MHz
Yb single mode fiber amp (3stage) output
Spectrum Pulse train
Output power85mW
* Repetition frequency : 10MHz* Wavelength Center : 1030nm , FWHM : 2nm
Yb-doped PCF amp & EO module Pulse picker
1030nm Fiber laser system
Improvement• Increase the stability of oscillator• Reduce the ASE of pre-amplifier• Increase the amp efficiency• Reduce the noise signal of 52 MHz (Pulse picker)
Yb fiber laser system on the ground
Menlo1030nm oscillator
Grating stretcher(Transmission)
SOApulse picker
Yb single mode fiber amp
Yb-doped double clad fiber amp
Repetition frequency114.24MHz
Wavelength selection1030nm & 1064nm
Repetition frequency 10MHz
Nd:YAG regenerative amplifier
EO modulepulse picker
Repetition frequency : 10Hz Yb:YAG Thin disk
regenerative amplifier
1030nm oscillator(ANDi type)
1064nm oscillator(ANDi type)
Output(1030nm)
Output(1064nm)
ASE rejection grating pair
1030nm1064nm
1064nm
Fiber part
Produce from MenlosystemsORANGE-Comb-250
• 1025-1050nm
• ~30mW
• 1-4ps
• 114.24MHz&2,856MHz
SYNCRONIZATION
New design Oscillator
Dissipative Soliton
Self-similar
All-normal-dispersion (ANDi) Oscillator
Yb-doped Fiber Oscillator
Breathing ratio >100
Breathing ratio <10
Oscillator for 1030 nm
CW oscillation Modelock oscillation
Bandpass filter: Semrock 1030nm (LL01-1030-12.5)• Tabs > 90% 1030 nm• FWHM of 3.9 nmOutput power > 130mW
1064nm Oscillator (ANDi type)
1064nm oscillator(ANDi type)
Spectrum
Pump power [mW]
(LD current [mA])
Output power [mW]
460(700)
75.2
Pulse train
Bandpass filter: Semrock 1064nm (LL01-1064-12.5)• Tabs > 90% 1064 nm• FWHM of 3.9 nm
The spectrum of the oscillators
◆High output power ◆ Tunable center wavelength
Selection of Oscillator
Selection of oscillatorMenlo oscillator
orangeANDi
oscillator1064nm
ANDi oscillator1030nm
Output:30mW @Menlo110mW @1030nm75mW @1064nm
Grating stretcher
Simplified schematic2nm@1030nm 0.5nm@1064nm
SOA pulse picker & Yb single mode fiber amp
Yb single mode fiber amp
SOA input[μW]
SOA output[μW]
Yb single mode amp output
[mW]
1030nm 330 400 135
1064nm 250 710 46
SOA pulse picker
1030nm 1064nm
Repetition frequency : 10MHz ASE of SOA
Grating pair for ASE remove @ 1064nm
ASE spectrum of SOA
1064nm pulse train
Before(power : 82mW)
After(power : 46mW)
Yb-doped double clad fiber amp
Pulse train Spectrum
Output power : 1.0 W(Pump power : 4W)
Fiber laser system layout on the ground
3 oscillators (100 MHz) 2 fiber system for 1030nm/1064nm SOA pulse picker Yb-doped fiber amplifier (~1.0 W)