present status of
DESCRIPTION
Present status of. LAPP – 10 / 03 / 2010. Previous photodiodes. Virgo set of photodiodes Hammamatsu InGaAs Ø = 3mm η > 95 % typ. IdarkTRANSCRIPT
DETDET
Present status of
LAPP – 10 / 03 / 2010
1
DETDETDETDET
Previous photodiodes
● Virgo set of photodiodes • Hammamatsu
• InGaAs
• Ø = 3mm
• η > 95 % typ.
• Idark <10 nA @ Vbias = 10 V
• Brkdown volt. = 50 V
• Imax ~ 100 mA
• fc ~ 70 MHz– Rs ~ 8 – 10 Ω
– Cs < 280 pF @ Vbias = 10 V
2
DETDETDETDET
Advanced requirements
● Increase of the modulation frequency• fmax ~ 2 x 70 Mhz
● Increase of incident power • Photodiodes should handle ~ 200 mW
● Resulting requirements for AdV photodiodes• Basically the same as for Virgo
• Plus :– lower Cs (with the same Ø)
– Increase Imax
3
DETDETDETDET
Review of current photodiodes
● Exhaustive review of commercial solutions• 8 manufacturers
– Hammamatsu, Perkin Elmer, Roithner, Fermionics, GPD, eGtran, EOS, Judson
• No major tech improvements for 10 yrs
• Pre selection :– Only 3 remaining manufacturers from which we bought samples
Perkin Elmer (x 5) Fermionics (x 3) Judson (x 2)
• Those samples are under characterization– use of Virgo preamp.
4
DETDETDETDET
I Dark
5
DETDETDETDET
Equivalent electrical scheme
6
● LCR meter
● Perkin Elmer● fc ~ 93 MHz
● Fermionics● fc ~ 41 MHz
● Judson● fc ~ 468 MHz
DETDETDETDET
DC Linerarity measurements
● Measurement are made by varying the source intensity• beam splitter• the emitted power is measured using a powermeter
● At present• met some difficulties to obtain a reliable absolute measurement
– comparison of several pwm are out of the +/- 4% measurement accuracy
• no coating
● First estimation of η• Perkin Elmer ~ 80 %• Fermionics ~ 60 %• Judson ~ 40 %
7
DETDETDETDET
Frequency response
● We investigate several way of modulating the intensity beam on a wide range of frequency (typ 1- 100 MHz)• AOM (fiber or not)
– high frequency limited
• pockels cells– difficulties to reach good modulation index on the whole frequency
range
● Commercial solution from photline• fiber EOM
• from 100 kHz up to 250 MHz
• delivered within 5 weeks
• output power limited to some 10mW
8
DETDETDETDET
PE0794
9
DETDETDETDET
PE0795
10
DETDETDETDET
PE0796
11
DETDETDETDET
PE0797
12
DETDETDETDET
PE0798
13
DETDETDETDET
F1
14
DETDETDETDET
F2
15
DETDETDETDET
F3
16
DETDETDETDET
J1
17
DETDETDETDET
J2
18
DETDETDETDET
Commandes passées
● Perkin Elmer
• 5 photodiodes – 1950 € HT
• Commandées le 03/11/09
• Livraison : 8 à 14 semaines
● Fermionics
• 3 photodiodes – 802 € HT
• Commandées le 05/11/09
• Livraison : 1 à 2 semaines
● Judson
• 2 photodiodes – 1861 € HT
• Commandées le 12/11/09
• Livraison : 2 à 4 semaines
19