THORLABS PDF10C2 User manual

Femtowatt Photoreceiver
PDF10C2
Operation Manual
2021

Version:
Date: 1.0 10-Nov-2021
Copyright © 2021 Thorlabs

Foreword
Contents
1 General Information 1
11.1 Ordering Codes and Accessories
2 Getting Started 2
22.1 Parts List 22.2 Preparation
3 Operating Instruction 3
33.1 Operating Elements 33.2 Mounting 33.3 Operation 43.4 Recommendations 63.5 Operating Principle 63.5.1 Optical Input 63.5.2 Electrical Output
4 Maintenance and Service 7
5 Appendix 8
85.1 Technical Data 95.2 Typical Responsivity 95.3 Typical Frequency Response 105.4 Typical Spectral Noise 105.5 Typical Output Time Response 115.6 Drawings 125.7 Safety 135.8 Certifications and Compliances 145.9 Return of Devices 145.10Manufacturer Address 145.11Warranty 145.12Exclusion of Liability and Copyright 155.13Thorlabs Worldwide Contacts and WEEE poilicy

© 2021 Thorlabs
We aim to develop and produce the best solutions for your
applications in the field of optical measurement techniques. To help
us to live up to your expectations and constantly improve our
products, we need your ideas and suggestions. We and our
international partners are looking forward to hearing from you.
Thorlabs GmbH
Warning
Sections marked by this symbol explain dangers that might result in
personal injury or death. Always read the associated information
carefully before performing the indicated procedure.
Please read this advice carefully!
This manual also contains "NOTES" and "HINTS" written in this form.
Attention
Paragraphs preceded by this symbol explain hazards that could
damage the instrument and the connected equipment or may cause
loss of data.
Note

1 General Information
Rev: 1.0, 10-Nov-2021 © 2021 Thorlabs Page 1
1 General Information
The Thorlabs PDF10C2 Femtowatt Photoreceivers combines a low-noise InGaAs photodiode
with a specially designed ultra-low-noise, fixed-gain transimpedance amplifier with extremely
high gain of up to 1011 V/A. This combination results in a photoreceiver with femtowatt sensitiv-
ity and an exceptionally low NEP, making it ideal for low-light level detection applications, such
as spectroscopy and fluorescence measurements. Direct detection of optical power down to
~10 fW is possible. In combination with an optional lock-in amplifier, sub-femtowatt sensitivity
can be achieved.
Due to a very high sensitivity, the PDF10C2 Femtowatt Photoreceiver can replace photomulti-
plier tubes (PMTs), avalanche photodiodes (APDs), and liquid-nitrogen-cooled germanium pho-
todiodes in many applications. No expensive high-voltage power supply or cooling is required.
Another advantage is that the PDF10C2 cannot be damaged by unwanted ambient light, which
is critical for many photomultiplier tubes.
The PDF10C2 detector housing can be integrated in optical setups using convenient 8-32 and
M4 combi-thread mounting holes that are compatible with both imperial and metric threading.
Please see the chapter Mounting for details.
The housing accommodates Thorlabs' SM05 (0.535"-40) and SM1 (1.035"-40) threaded adap-
ters and accessories. This allows convenient mounting of external optics, light filters, and aper-
tures. The product includes an SM1 Coupler Body (SM1T1), which adapts the external thread
to an internal thread and holds the SM1RR Retaining Ring, and a reusable protective plastic
cover cap. For accessories, please visit our website or contact Thorlabs .
A ±12 VDC power supply is included with each amplified photodetector. The appropriate input
voltage (100 VAC, 120 VAC, 230 VAC) can be selected with a switch on the power supply .
Attention
Please find all safety information and warnings concerning this product in the chapter Safety
in the Appendix.
1.1 Ordering Codes and Accessories
PDF10C2 Femtowatt Photoreceiver, InGaAs detector, 800 - 1700nm, Bandwidth DC-20Hz,
Round Active Area 0.2 mm2(Ø 0.5 mm), Combi-Thread Mounting Holes Compatible
with 8-32 and M4 Threads
Included Accessories
·LDS12B Power Supply (±12V, 0.2A), 100 VAC, 120 VAC or 230 VAC Line Voltage
·Plastic Cover Cap (Item # SM1EC2B) on an included SM1T1 SM1 Coupler with a SM1RR
SM1 Retaining Ring.
Optional Accessories
·All Thorlabs internal SM1 (1.035"-40) and external SM05 (0.535"-40) threaded accessories
are compatible with the PDF10C2.
·Fiber adapter of the Thorlabs S120-xx. These fiber adapter can be mounted on the optical in-
put for fiber coupled applications.
·PDA-C-72 DC power supply cable to PDF10C2: This cable has a connector on one end and
open wires at the other. The pin-out of the PDF10C2 DC power jack is shown in the ap-
pendix .
Please visit our homepage http://www.thorlabs.com for various accessories like fiber adapters,
posts and post holders, data sheets and further information.
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PDF10C2
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2 Getting Started
2.1 Parts List
Please inspect the shipping container for damage. Do not cut through the cardboard. You might
need the box for storage or returns.
If the shipping container seems to be damaged, keep it until you have inspected the contents
mechanically and electrically.
Verify that you have received the following items within the package:
1. PDF10C2 Amplified Photodetector
2. Plastic Cover Cap (Item # SM1EC2B) on SM1T1-SM1 Coupler with an SM1RR-SM1
Retaining Ring
3. LDS12B Power Supply (±12V, 0.2A), 100 VAC, 120 VAC or 230 VAC Line Voltage
4. Quick Reference
2.2 Preparation
Carefully unpack the unit and accessories. If any damage is noticed, do not use the unit.
Contact Thorlabs and have us replace the defective unit.
Note
Prior to operation, please check if the indicated line voltage range on the power supply matches
with your local mains voltage! Adjust the power supply accordingly to 100 VAC, 120 VAC or
230 VAC.
Note
If you prefer to use your own power supply, please ask Thorlabs for an appropriate power
connector cable .
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3 Operating Instruction
Rev: 1.0, 10-Nov-2021 © 2021 Thorlabs Page 3
3 Operating Instruction
3.1 Operating Elements
PDF10C2
3.2 Mounting
Housing
The PDF10C2 is housed in a rugged, shielded, 70.9 mm x 49.9 mm x 22.5 mm aluminum en-
closure.
Mounting PDF10C2 on an Optical Table
Mount the PDF10C2 on an optical post by using either of the two tapped mounting holes on the
side and bottom. The combi-thread tapped holes accept both 8-32 and M4 threads, such that
using either imperial or metric TR posts is possible.
Mounting External Optics
The PDF10C2 housing accommodates Thorlabs’ SM05-threaded (0.535"-40) and SM1-
threaded (1.035"-40) adapters that are compatible with any number of Thorlabs 1” and ½”
threaded accessories. This allows to mount external optics, filters, apertures, fiber adapters,
lens tubes, or cage systems. For accessories, please visit our website or contact Thorlabs .
The PDF10C2 comes with an SM1T1 SM1 coupler that adapts the external thread to an SM1
internal thread. A retaining ring in the coupler holds the protective cover cap. Please unscrew
the coupler if needed.
3.3 Operation
Attention
Ensure that the correct mains voltage is selected on the power supply prior to connecting the
power supply to the mains power. Wrong settings for the mains voltage may damage the power
supply. The ±12 V, 250 mA power supply is included; no high voltage power supply is required
for operation.
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PDF10C2
Page 4 MTN013713_D02
Attention
Refer to the Technical Data and pay attention to the optical damage threshold of 10 mW!
Exceeding this value will permanently destroy the detectors!
Attention
Due to limitations in the IC, the high-speed amplifier used in these devices may become un-
stable, exhibiting oscillations or negative output, if the power supply voltage is initially applied
when the module is switched on. Therefore, please make sure the power-on switch on your
PDF10C2 is in OFF position 0(see Operating Elements ) prior to connecting the external
power supply.
Electrical Setup
·Mount the detector as described above and make sure the PDF10C2 is switched off.
·Plug the power connector cable into the DC INPUT LDS12B connector of the PDF10C2.
·Plug the power supply into an outlet.
·Connect OUTPUT to your data acquisition device with a coaxial cable. The PDF10C2 with
femtowatt sensitivity is a low-frequency device that should only be terminated into high impe-
dance (Hi-Z) loads.
·Switch on the power supply.
·Switch on the PDF10C2 by moving the power slider to I while the optical input is protected by
the cover cap.
·The maximum OUTPUT voltage swing is ±10 V for high impedance loads (>10 kW). The
OUTPUT signal should stay below this maximum output voltage to avoid amplifier saturation.
Optical Setup
·Ensure that OUTPUT offset voltage is within the range listed in Technical Data . A small
drift during the warm up period (~5 min) is typical.
·Check whether the noise level is below 5 mVRMS. If the noise level is significantly higher,
please refer to recommendations and optimize your setup.
·Remove the plastic cover cap that protects the optical input.
·Mount external optics if needed.
·Align the light source with the optical input.
·It is recommended to focus the optical signal out of a fiber onto the detector.
·To prevent saturation of the amplifier keep the optical input powers below the CW saturation
power listed in Technical Data . External neutral density filters or attenuators are
recommended to reduce the input light level in critical cases.
·For maximum linearity performance and to prevent damage to the detector when measuring
focused beams, fiber outputs, or small diameter beams, do not exceed a maximum input
power of 10 mW/cm2.
Turning off the PDF10C2
Move the power slider to 0 after finishing the measurements.
3.4 Recommendations
·Optical Alignment
oAn open beam should always be carefully aligned with the detector. Due to the small active
area of the PDF10C2 photodiode, it is recommended to focus the optical signal out of a
fiber onto the detector. For this and other fiber-coupled applications, fiber adapters like
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3 Operating Instruction
Rev: 1.0, 10-Nov-2021 © 2021 Thorlabs Page 5
Thorlabs S120-xx series can be mounted on the optical input. The fiber adapters accom-
modate multi-mode or single-mode fibers.
oPlease note that coupling losses may occur due to the small detector size. This will result in
a reduced output signal. If angled connectors are used, an FC adapter can be rotated from
its original position to improve the alignment. For this process apply an input signal with
power below the saturation level while observing the output voltage using a digital voltmeter
or other low-frequency measurement device.
·Ambient or Stray Light
oPDF10C2 photodetector is an extremely sensitive device. To reduce the noise level, careful
shielding of the PDF10C2 from any unwanted light sources is essential. Common tech-
niques are baffling or other opaque barriers like black cloths or beam tubes. Even a small
power-on indicator LED far away from the PDF10C2 can affect power measurements at
femtowatt levels.
oIt is not necessary to switch off the PDF10C2 when it is exposed to ambient light. The amp-
lifier will saturate but, unlike photomultiplier tubes, it will not be damaged or saturated for a
long period of time.
oIt is highly recommended to use appropriate bandpass filters in front of the detector to mini-
mize the influence of stray light.
·High Optical Input Power
oTo avoid permanent damage to the detector, do not exceed the specified optical damage
threshold of 10 mW as specified in section Technical Data .
oKeep the optical input power below the CW saturation power listed in the Technical Data
to avoid electrical saturation.
·Amplifier Saturation
To avoid electrical saturation of the amplifier keep the output voltage Vout below the maximum
listed in Technical Data . External neutral density filters or attenuators are recommended to
reduce the input light level in critical cases.
·Electrostatic Coupling
Electrostatic coupling of electrical noise associated with ground loops can be critical. In most
cases an electrically isolated post (e.g. Thorlabs item# TRE or TRE/M) will suppress elec-
trical noise coupling. Always try to identify electrical noise sources and increase the distance
to the PDF10C2. If possible, rotate the PDF10C2 input away from the noise source. Different
common ground points can also be tested.
·Impact of Temperature
oThe amplifier offset voltage is factory set to zero at 23 °C ambient temperature. Due to the
very high transimpedance gain, even small temperature changes or even humidity changes
may affect the offset voltage. Therefore it is recommended for precise DC light level mea-
surements to use the PDF10C2 in an environment with constant temperature after a short
warm up period (~5 min).
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PDF10C2
Page 6 MTN013713_D02
3.5 Operating Principle
The Thorlabs PDF10C2 Femtowatt Photoreceiver combines a low noise InGaAs photodiode
with a specially designed ultra low noise transimpedance amplifier with extremely high gain.
This unique combination results in a photoreceiver with femtowatt sensitivity due to its excep-
tional low NEP and makes it ideal for low-light level detection applications, such as spectro-
scopy and fluorescence measurements. Direct detection of optical power down to ~10 fW is
possible.
3.5.1 Optical Input
Optical Beam Alignment
The InGaAs Photodiode of the PDF10C2 has a round detector active area of 0.2 mm2with a
diameter of Æ0.5 mm.
Due to this small active area of the PDF10C2 photodiode, it is recommended to focus the op-
tical signal out of a fiber onto the detector.
Because the housing is compatible with any number of Thorlabs 1” and ½” threaded accessor-
ies, external optics, filters or apertures can be easily attached to the PDF10C2.
Detector Sensitivity
The PDF10C2 is specified for determined wavelength ranges . The typical responsivity curve
can be found in the appendix . Please note that this femtowatt photoreceiver is extremely
sensitive to unwanted stray light.
3.5.2 Electrical Output
Responsivity
The Thorlabs PDF10C2 delivers an output voltage, which is a function of incident light power
POPT, detector responsivity Â(l) and transimpedance gain G given by:
V =P ( ) G
OUT OPT
l × ×
The responsivity Â(l) for a given wavelength can be read from the diagram Typical Responsi-
vity to estimate the output voltage. Please note that transimpedance gain tolerance is ±10%
for an individual unit due to extremely high feedback resistors used for the transimpedance
amplifier. Temperature changes or even humidity changes may affect transimpedance gain.
Output Voltage
The maximum output voltage is 10 V for high impedance loads (>10 kW). The output signal
should stay below the maximum output voltage to avoid saturation. Depending on wavelength
responsivity Â(l)of the detector, the amplifier will reach saturation at optical input power
greater than the CW Saturation Power listed in Technical Data .
Note
Typical curves for the Frequency Response , Spectral Noise Distribution and Output Time
Response can be found in the appendix.
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4 Maintenance and Service
Rev: 1.0, 10-Nov-2021 © 2021 Thorlabs Page 7
4 Maintenance and Service
Protect the PDF10C2 from adverse weather conditions. The PDF10C2 is not water resistant.
Attention
To avoid damage to the instrument, do not expose it to spray, liquids or solvents!
The unit does not need a regular maintenance by the user. It does not contain any modules
and/or components that could be repaired by the user. If a malfunction occurs, please contact
Thorlabs for return instructions.
Do not remove covers!
Do not open the power supply unit!
Cleaning
To clean the PDF10C2 housing, use a mild detergent and damp cloth. Do not soak the unit in
water or use solvent based cleaners.
When cleaning the window of the photodetector, please remember that is a sensitive optical
device. Gently blow off any dust using compressed air and wipe gently with an optic tissue wet-
ted with isopropanol.
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PDF10C2
Page 8 MTN013713_D02
5 Appendix
5.1 Technical Data
Item#
PDF10C2
Specifications
Detector Material
InGaAs / PIN
Detector Wavelength Range
800 - 1700 nm
Typical Max. Responsivity
1.0 A/W @ 1550 nm
Detector Active Area
0.2 mm2 (Æ 0.5 mm)
Transimpedance Gain
1 x 1011 V/A ±10%
Max. Conversion Gain
1 x 1011 V/W ±10%
Output Bandwidth (3dB)
DC - 20 Hz
Rise/Fall Time (10% -90%)
19 ms
CW Saturation Power
100 pW
Max. Input Power
(Photodiode Damage Threshold))
10 mW
Minimum NEP (DC - 3dB bandwidth)
7.5 fW/ÖHz
Integrated Noise (DC - 3dB bandwidth)
35 fWRMS
Overall Output Voltage Noise (Typ.)
3.5 mVRMS
Electrical Output, Impedance
BNC, 200 Ω
Maximum Output Voltage
10 V
DC-Offset Electrical Output
< ±75 mV
General Specifications
Size
70.9 mm x 49.9 mm x 22.5 mm
Power Supply
±12V, 250 mA
Operating Temperature Range
10°C to 50°C
Storage Temperature Range
-25°C to 70°C 2)
All technical data are valid at 23 ± 5°C and 45 ± 15% rel. humidity
2) non condensing

5 Appendix
Rev: 1.0, 10-Nov-2021 © 2021 Thorlabs Page 9
5.2 Typical Responsivity
PDF10C2 Typical Detector Responsivity
5.3 Typical Frequency Response
For the measurement of the frequency response, a test signal was fed through an optical chop-
per and fiber-coupled to the PDF10C2 input. The output voltage amplitude was measured with
an oscilloscope.
PDF10C2 Typical Frequency Response

PDF10C2
Page 10 MTN013713_D02
5.4 Typical Spectral Noise
Noise is being characterized by different specifications. The spectral noise of PDF10C2 was
measured using a 200 kSample/s A/D converter. The power density spectrum was calculated
from the sampled values with respect to transimpedance gain and detector responsivity. The
optical input of the PDF10C2 was blocked.
Other noise specifications are the NEP (Noise Equivalent Power) and the overall RMS output
noise, specified for a defined bandwidth. These parameters are stated in Technical Data ).
PDF10C2 Typical Spectral Noise
5.5 Typical Output Time Response
Rise/fall time measurements were carried out with the same setup described in the typical fre-
quency response.
PDF10C2 Typical Output Time Response
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5 Appendix
Rev: 1.0, 10-Nov-2021 © 2021 Thorlabs Page 11
5.6 Drawings
Dimensions of PDF10C2

PDF10C2
Page 12 MTN013713_D02
5.7 Safety
Attention
The safety of any system incorporating the equipment is the responsibility of the assembler of
the system.
All statements regarding safety of operation and technical data in this instruction manual will
only apply when the unit is operated correctly as it was designed for.
The PDF10C2 must not be operated in explosion endangered environments.
Do not remove covers. There are no user-serviceable parts inside.
This precision device is only serviceable if returned and properly packed into the complete ori-
ginal packaging including the cardboard insert that holds the enclosed devices. If necessary,
ask for replacement packaging. Refer servicing to qualified personnel.
Changes to this device cannot be made nor may components not supplied by Thorlabs be used
without written consent from Thorlabs.
Attention
Prior to applying power to the PDF10C2, make sure that the protective conductor of the 3 con-
ductor mains power cord is correctly connected to the protective earth ground contact of the
socket outlet! Improper grounding can cause electric shock resulting in damage to your health
or even death!
Ensure that the line voltage setting of the power supply agrees with your local supply and that
the corresponding fuses are inserted. If not, please change the line voltage setting (see section
Preparation ).
To avoid risk of fire, only the appropriate fuses for the corresponding line voltage must be used.
All modules must only be operated with duly shielded connection cables.
Users that change or modify the product described in this manual in a way not expressly ap-
proved by Thorlabs (party responsible for compliance) could void the user’s authority to operate
the equipment.
Thorlabs GmbH is not responsible for any radio television interference caused by modifications
of this equipment or the substitution or attachment of connecting cables and equipment other
than those specified by Thorlabs. The correction of interference caused by such unauthorized
modification, substitution or attachment will be the responsibility of the user.
The use of shielded I/O cables is required when connecting this equipment to any and all op-
tional peripheral or host devices. Failure to do so may violate FCC and ICES rules.
Attention
Mobile telephones, cellular phones or other radio transmitters are not to be used within the
range of three meters of this unit since the electromagnetic field intensity may then exceed the
maximum allowed disturbance values according to IEC 61326-1.
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5 Appendix
Rev: 1.0, 10-Nov-2021 © 2021 Thorlabs Page 13
5.8 Certifications and Compliances

PDF10C2
Page 14 MTN013713_D02
5.9 Return of Devices
This precision device is only serviceable if returned and properly packed into the complete ori-
ginal packaging including the complete shipment plus the cardboard insert that holds the en-
closed devices. If necessary, ask for replacement packaging. Refer servicing to qualified per-
sonnel.
5.10 Manufacturer Address
Manufacturer Address Europe
Thorlabs GmbH
Münchner Weg 1
D-85232 Bergkirchen
Germany
Tel: [phone]
Fax: [phone]
www.thorlabs.de
Email: [email protected]
EU-Importer Address
Thorlabs GmbH
Münchner Weg 1
D-85232 Bergkirchen
Germany
Tel: [phone]
Fax: [phone]
www.thorlabs.de
Email: [email protected]
5.11 Warranty
Thorlabs warrants material and production of the PDF10C2 for a period of 24 months starting
with the date of shipment in accordance with and subject to the terms and conditions set forth
in Thorlabs’ General Terms and Conditions of Sale which can be found at:
General Terms and Conditions:
https://www.thorlabs.com/Images/PDF/LG-PO-001_Thorlabs_terms_and_%20agreements.pdf
and
https://www.thorlabs.com/images/PDF/Terms%20and%20Conditions%20of%
20Sales_Thorlabs-GmbH_English.pdf
5.12 Exclusion of Liability and Copyright
Thorlabs has taken every possible care in preparing this document. We however assume no li-
ability for the content, completeness or quality of the information contained therein. The content
of this document is regularly updated and adapted to reflect the current status of the product.
All rights reserved. This document may not be reproduced, transmitted or translated to another
language, either as a whole or in parts, without the prior written permission of Thorlabs. Copy-
right © Thorlabs 2021. All rights reserved.
Please refer to the general terms and conditions linked under Warranty .
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5 Appendix
Rev: 1.0, 10-Nov-2021 © 2021 Thorlabs Page 15
5.13 Thorlabs Worldwide Contacts and WEEE poilicy
For technical support or sales inquiries, please visit us at www.thorlabs.com/contact for our
most up-to-date contact information.
USA, Canada, and South America
Thorlabs, Inc.
[e-mail]
[e-mail]
UK and Ireland
Thorlabs Ltd.
[e-mail]
[e-mail]
Europe
Thorlabs GmbH
[e-mail]
Scandinavia
Thorlabs Sweden AB
[e-mail]
France
Thorlabs SAS
[e-mail]
Brazil
Thorlabs Vendas de Fotônicos Ltda.
[e-mail]
Japan
Thorlabs Japan, Inc.
[e-mail]
China
Thorlabs China
[e-mail]
Thorlabs 'End of Life' Policy (WEEE)
Thorlabs verifies our compliance with the WEEE (Waste Electrical and Electronic Equipment) direct-
ive of the European Community and the corresponding national laws. Accordingly, all end users in
the EC may return “end of life” Annex I category electrical and electronic equipment sold after
August 13, 2005 to Thorlabs, without incurring disposal charges. Eligible units are marked with the
crossed out “wheelie bin” logo (see right), were sold to and are currently owned by a company or in-
stitute within the EC, and are not dissembled or contaminated. Contact Thorlabs for more informa-
tion. Waste treatment is your own responsibility. “End of life” units must be returned to Thorlabs or
handed to a company specializing in waste recovery. Do not dispose of the unit in a litter bin or at a
public waste disposal site. It is the users responsibility to delete all private data stored on the device
prior to disposal.

www.thorlabs.com