THORLABS PDA10DT User manual

PDA10DT(-EC)
Amplified InGaAs
Detector
User Guide

Amplified InGaAs Detector
Table of Contents
Chapter 1 Warning Symbol Definitions ...........................................0
Chapter 2 Description........................................................................1
Chapter 3 Setup..................................................................................2
Chapter 4 Operation...........................................................................4
4.1. Output..........................................................................4
4.2. Gain Adjustment...........................................................4
4.3. Bandwidth Filter Adjustment.........................................5
4.4. Thermoelectric Cooler ...................................................5
4.5. Light-to-Voltage Conversion..........................................5
Chapter 5 Maintenance......................................................................6
Chapter 6 Troubleshooting...............................................................6
Chapter 7 Specifications...................................................................7
Chapter 8 Drawings .........................................................................13
Chapter 9 Regulatory.......................................................................14
Chapter 10 Certificate of Conformance ...........................................15
Chapter 11 Thorlabs Worldwide Contacts.......................................16

Amplified InGaAs Detector Chapter 1: Warning Symbol Definitions
Page 0 13129-D02
Chapter 1 Warning Symbol Definitions
Below is a list of warning symbols you may encounter in this manual or on your
device.
Symbol
Description
Direct Current
Alternating Current
Both Direct and Alternating Current
Earth Ground Terminal
Protective Conductor Terminal
Frame or chassis Terminal
Equipotentiality
On (Supply)
Off (Supply)
In Position of a Bi-Stable Push Control
Out Position of a Bi-Stable Push Control
Caution, Risk of Electric Shock
Caution, Hot Surface
Caution, Risk of Danger
Warning, Laser Radiation
Caution, Spinning Blades May Cause Harm

Amplified InGaAs Detector Chapter 2: Description
Rev M, September 7, 2021 Page 1
Chapter 2 Description
The PDA10DT is an amplified, thermoelectrically cooled, switchable-gain,
switchable-bandwidth, InGaAs photoconductive detector. The detector is DC
coupled. It is sensitive over a wavelength range of 0.9 to 2.57 µm. Two eight-
position rotary switches allow the user to vary the gain in 10 dB steps and select
low-pass filter bandwidth settings from 500 Hz to 1 MHz. A buffered output drives
50 Ωload impedances up to 5 V. The first two gain steps (0 dB and 10 dB) are
biased to -2 V for best high-speed performance while the remaining gain steps are
unbiased for high precision measurements.
The detector is mounted on a thermoelectric cooler and factory set to cool the
detector to -10 °C with a thermistor providing feedback to maintain a constant
temperature. This cooling provides higher detectivity (D*), which results in a lower
offset at the output and allows higher gains. It also reduces thermally generated
noise. The housing acts as a heat sink and includes a fan to increase the cooling
capacity. It is important to note that the cooling fan will keep the heat sink at room
temperature. Without it, the heat sink will warm up, causing a higher temperature
drop from the heat sink to the detector element, resulting in larger TEC currents.
Without the fan, the TEC current will operate at its limit (~820 mA) and the detector
element will no longer be temperature stabilized. Offsets will increase and
fluctuate, and output noise will increase. For best results do not block, limit airflow
to, or stop the cooling fan.
The detector housing has an internally SM1-threaded (1.035"-40) mounting
aperture, which is compatible with any SM1-threaded accessory. The device ships
with an SM1RR Retaining Ring allowing convenient mounting of optics, light filters,
apertures, etc. The SM1-threaded mount can be easily integrated into our cage
and lens tube systems.
The PDA10DT(-EC) has two 8-32 (M4) tapped holes for mounting the detector on
a Ø1/2" optical post in one of two perpendicular directions. The detector includes
a 100 - 240 V, 47 - 63 Hz power supply.

Amplified InGaAs Detector Chapter 3: Setup
Page 2 13129-D02
Chapter 3 Setup
CAUTION
Mount the unit in a position that does not block airflow to the fan and heat sink.
Figure 1 Electrical Connections
1. Unpack the detector head.
2. (Optional) Install a Thorlabs Ø1/2" diameter TR Post (not included) into
one of the 8-32 tapped holes (M4 in -EC version) located on the bottom
and side of the head, and mount into a PH Post Holder (not included).
3. Connect the 4-pin power supply plug into the power receptacle on the
PDA10DT.
4. Plug the power supply into a 47 to 63 Hz, 100 to 240 VAC outlet.
5. Attach a 50 ΩBNC cable to the output of the PDA. When running cable
lengths longer than 12", we recommend terminating the opposite end of
the coax with a 50 Ωresistor (Thorlabs’ T4119 BNC in-line terminator) for
maximum performance. Connect the remaining end to a measurement
device such as an oscilloscope or high-speed DAQ card.
CAUTION
Many high speed oscilloscopes have input impedances of 50 Ω. In this case, do
not install a 50 Ωterminator. The combined loads will equal 25 Ωwhich could
allow ~135 mA of output current. This will damage the output driver of the
PDA10DT.
Power Supply
Connection
Power Indicator
LED
Output BNC
Connector
50 Ω

Amplified InGaAs Detector Chapter 3: Setup
Rev M, September 7, 2021 Page 3
6. Turn on the PDA10DT using the power switch located on the top side of
the detector.
7. Install any desired filters, optics, adapters, or fiber adapters to the input
aperture.
CAUTION
The PDA10DT was designed to allow maximum accessibility to the
photodetector by having the front surface of the diode flush with the outside of
the PDA housing. When using fiber adapters, make sure that the fiber ferrule
does not crash into the detector. Failure to do so may cause damage to the
diode and/or the fiber. Installing an SM1RR Retaining Ring (included) inside the
1" threaded coupler before installing the fiber adapter will prevent damage.
8. Apply a light source to the detector. Adjust the gain to the desired setting.
Note: Allow a minute for the TEC controller to stabilize the temperature.
For best results, allow the unit to warm up for about 30 minutes.
CAUTION
Saturation of the output signal may cause damage to the InGaAs detector
element.

Amplified InGaAs Detector Chapter 4: Operation
Page 4 13129-D02
Chapter 4 Operation
The PDA10DT is an amplified InGaAs photoconductive detector. The DC-coupled
amplifier circuit is designed to minimize noise.
Figure 2 Gain Control, LPF Control, and Power Selector
4.1. Output
The maximum output of the PDA10DT is 10 V for high impedance loads (i.e. RLOAD
> 5 kΩ) and 5 V for 50 Ωloads. Adjust the gain so that the measured signal level
out of the PDA10DT is below 10 V (5 V for a 50 Ωload) to avoid saturation. If
necessary, use external neutral density filters to reduce the input light level. The
BNC output signal is buffered with an amplifier capable of driving 50 Ωloads. A
50 Ωseries resistor is included on the output to impedance match a 50 Ωcoax
cable. For best performance, we recommend operating the PDA10DT with a 50 Ω
terminating load located at the end of the coax cable. While this is not necessary,
it eliminates ringing and distortion due to impedance mismatches.
4.2. Gain Adjustment
The PDA10DT includes a low-noise, low-offset, high-gain amplifier that allows gain
adjustment over a 70 dB range. The gain is adjusted by rotating the gain control
knob located on the side of the unit. There are 8 gain positions incremented in 10
dB steps. To adjust the gain, follow the steps below.
1. Set the gain switch to 0 dB.
2. Turn on the light source.
3. Adjust the gain setting making sure the output of the detector is below the
saturation level as indicated by section 4.1 above.
Power Toggle Switch
Gain Switch
Bandwidth
Switch

Amplified InGaAs Detector Chapter 4: Operation
Rev M, September 7, 2021 Page 5
4.3. Bandwidth Filter Adjustment
The PDA10DT also includes an adjustable low-pass filter with settings from
500 Hz to 1 MHz in 8 steps. This filter allows the user to optimize the PDA10DT to
operate at the lowest amount of high-frequency optical and electrical noise. The
filter is adjusted by rotating the filter control knob, located on the side of the unit.
To adjust the filter, follow the steps below:
1. Determine the maximum bandwidth required.
2. Set the filter bandwidth switch setting just above the desired bandwidth.
4.4. Thermoelectric Cooler
The thermoelectric cooler built into the detector is factory set to cool the detector
to -10 °C with a thermistor providing feedback to maintain a constant temperature.
The housing is used as a heat sink and includes a fan to increase the cooling
capacity. It is important to note that the cooling fan will keep the heat sink at room
temperature. Without it, the heat sink will warm up, causing a higher temperature
drop from the heat sink to the detector element, resulting in larger TEC currents.
Without the fan, the TEC current will operate at its limit (~820 mA) and the detector
element will no longer be temperature stabilized. Offsets will increase and
fluctuate, and output noise will increase. For best results do not block, limit airflow
to, or stop the cooling fan. This operation is automatic and requires no input or
adjustment by the user.
4.5. Light-to-Voltage Conversion
The Spectral Responsivity, (), can be obtained Spectral Response Curve on
page 15 to estimate the amount of output voltage to expect. The light-to-Voltage
conversion can be estimated by factoring the wavelength-dependent responsivity
of the InGaAs detector with the gain as shown below:
󰇛󰇜  
 󰇛󰇜  󰇛󰇜
For terminators with low resistance, <5 kΩor 1% error, an additional factor needs
to be included in the above formula. As described above, the output includes a 50
Ωseries resistor (RS). The output load creates a voltage divider with the 50 Ω
series resistor as follows:
  
󰇛  󰇜
Where RLOAD is the terminating resistor and RS= 50 Ω. For a standard 50 Ω
terminator, the gain will be scaled by 0.5 as shown below:
  
󰇛  󰇜 
󰇛󰇜  
 󰇛󰇜  󰇛󰇜 

Amplified InGaAs Detector Chapter 5: Maintenance
Page 6 13129-D02
Chapter 5 Maintenance
There are no serviceable parts in the PDA10DT detector or power supply. The
housing may be cleaned by wiping with a soft damp cloth. The window of the
detector should only be cleaned using isopropyl alcohol and optical grade wipes.
If you suspect a problem with your PDA10DT, please contact your local Thorlabs
technical support office and a member of our support team will be happy to assist
you.
Chapter 6 Troubleshooting
Problem
Suggested Solutions
There is no signal response.
Verify that the power is switched on and all
connections are secure.
Verify the proper terminating resistor is installed if
using a Voltage measurement device.
Verify that the optical signal wavelength is within
the specified wavelength range.
Verify that the optical signal is illuminating the
detector active area
Ensure, not to block, limit airflow to or stop the
cooling fan. It will overheat the devise and it will
affect its functionality.
Output Voltage will not increase.
Detector Output is skewed.
Check to make sure the detector is not saturated.
Refer to the Output Voltage spec. in the
Specifications table.
Install a 1" Lens Tube (SM1L10) to the thread
coupler (SM1T1) to baffle any external light
sources to see if this improves the response.

Amplified InGaAs Detector Chapter 7: Specifications
Rev M, September 7, 2021 Page 7
Chapter 7 Specifications
Specifications1
Optical Specifications
Wavelength Range
0.9 - 2.57 µm
Peak Wavelength (p)
2.3 µm
Peak Response (p)
1.3 A/W (Typ.)
Electrical Specifications
Gain Adjustment Range
70 dB
Gain Steps
8
Gain Settings (dB)
0, 10, 20, 30, 40, 50, 60, 70
Filter Steps
8
Filter Settings (kHz)
0.5, 1, 5, 10, 50, 100, 500, 1000
Output Voltage2
0 - 5 V (50 Ω)
0 - 10 V (Hi-Z)
Output Impedance
50 Ω
Max Output Current
100 mA
Load Impedance
50 Ω- Hi-Z
Offset3
20 mV (Typ.)
45 mV (Max)
Offset Drift (70 dB)
2.7 mV/°C
TEC Temperature
-10 °C
Bias Voltage
-2 V (0 dB and 10 dB)
0 V (20 dB - 70 dB)
1
All measurements performed with a 50 Ωload unless stated otherwise. The PDA10DT has a 50 Ω
series terminator resistor (i.e., in series with amplifier output). This forms a voltage divider with any load
impedance (e.g., 50 Ωload divides signal in half).
2
Saturation of the output voltage may cause damage to the InGaAs detector element.
3
After the temperature has stabilized on all gain steps. Also note that the worst case offset is on the
10 dB gain step.

Amplified InGaAs Detector Chapter 7: Specifications
Page 8 13129-D02
General Specifications
Detector
Extended InGaAs PIN
Active Area
0.8 mm2(Ø1.0 mm)
Surface Depth
0.08" (2.0 mm)
Output
BNC
Weight(Detector/Power Supply)
0.42 lbs / 0.82 lbs (191 g / 372 g)
Power Supply
30 W
Input Power
100 - 240 VAC, 47 –63 Hz
Storage Temperature
0 to 85 °C
Operating Temperature
0 to 30 °C
Accessories
SM1RR
Optical Head Size
3" x 2.2" x 2.2"
(76.2 mm x 55.9 mm x 55.9 mm)
Gain/LPF Switches
8-Pos Rotary
Gain Steps
8 x 10 dB steps
Filter Steps
8
Gain Adjustable Range
70 dB
Gain (Hi-Z)4
Low-Pass Filter
Bandwidth
NEP (pW/√Hz)5
0 dB
1.51 kV/A
1M
1 MHz
0 dB
15.9 @ DC - 2 MHz
10 dB
4.75 kV/A
500k
500 kHz
10 dB
8.27 @ DC - 1.5 MHz
20 dB
15.0 kV/A
100k
100 kHz
20 dB
2.8 @ DC - 700 kHz
30 dB
47.5 kV/A
50k
50 kHz
30 dB
1.68 @ DC - 250 kHz
40 dB
151 kV/A
10k
10 kHz
40 dB
1.33 @ DC - 150 kHz
50 dB
475 kV/A
5k
5 kHz
50 dB
1.88 @ DC - 20 kHz
60 dB
1500 kV/A
1k
1 kHz
60 dB
2.22 @ DC - 7 kHz
70 dB
4750 kV/A
500
500 Hz
70 dB
2.11 @ DC - 2.5 kHz
4
Gain with a 50 Ωload is one-half the hi-Z gain. All values are ±2%.
5
NEP values measured using a 50 Ω load and a low-pass filter setting of 1MHz; calculated at the
detector’s peak responsivity wavelength.

Amplified InGaAs Detector Chapter 7: Specifications
Rev M, September 7, 2021 Page 9
Figure 3 PDA10DT Gain Bandwidth
Figure 4 PDA10DT Filter Bandwidth

Amplified InGaAs Detector Chapter 7: Specifications
Page 10 13129-D02
Figure 5 Noise at 70 dB Gain amd 500 Hz Bandwidth

Amplified InGaAs Detector Chapter 7: Specifications
Rev M, September 7, 2021 Page 11
Figure 6 Noise at 0 and 70 dB Gain and 1 MHz Bandwidth

Amplified InGaAs Detector Chapter 7: Specifications
Page 12 13129-D02
Figure 7 TEC Current vs. Temperature
Figure 8 Photosensitivity at -10 °C and 25 °C

Amplified InGaAs Detector Chapter 8: Drawings
Rev M, September 7, 2021 Page 13
Chapter 8 Drawings

Amplified InGaAs Detector Chapter 9: Regulatory
Page 14 13129-D02
Chapter 9 Regulatory
As required by the WEEE (Waste Electrical and Electronic Equipment Directive)
of the European Community and the corresponding national laws, Thorlabs offers
all end users in the EC the possibility to return "end of life" units without incurring
disposal charges.
•This offer is valid for Thorlabs electrical and electronic equipment:
•Sold after August 13, 2005
•Marked correspondingly with the crossed out
"wheelie bin" logo (see right)
•Sold to a company or institute within the EC
•Currently owned by a company or institute
within the EC
•Still complete, not disassembled and not
contaminated
As the WEEE directive applies to self-contained
operational electrical and electronic products, this end of
life take back service does not refer to other Thorlabs products, such as:
•Pure OEM products, that means assemblies to be built into a unit by the
user (e.g. OEM laser driver cards)
•Components
•Mechanics and optics
•Left over parts of units disassembled by the user (PCB’s, housings etc.).
If you wish to return a Thorlabs unit for waste recovery, please contact Thorlabs or
your nearest dealer for further information.
Waste Treatment is Your Own Responsibility
If you do not return an "end of life" unit to Thorlabs, you must hand it to a company
specialized in waste recovery. Do not dispose of the unit in a litter bin or at a public
waste disposal site.
Ecological Background
It is well known that WEEE pollutes the environment by releasing toxic products
during decomposition. The aim of the European RoHS directive is to reduce the
content of toxic substances in electronic products in the future.
The intent of the WEEE directive is to enforce the recycling of WEEE. A controlled
recycling of end of life products will thereby avoid negative impacts on the
environment.
Wheelie Bin Logo

Amplified InGaAs Detector Chapter 10: Certificate of Conformance
Rev M, September 7, 2021 Page 15
Chapter 10 Certificate of Conformance

Amplified InGaAs Detector Chapter 11: Thorlabs Worldwide Contacts
Page 16 13129-D02
Chapter 11 Thorlabs Worldwide Contacts
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.
[email protected]
[email protected]
UK and Ireland
Thorlabs Ltd.
[email protected]
[email protected]
Europe
Thorlabs GmbH
[email protected]
Scandinavia
Thorlabs Sweden AB
[email protected]
France
Thorlabs SAS
[email protected]
Brazil
Thorlabs Vendas de Fotônicos Ltda.
[email protected]
Japan
Thorlabs Japan, Inc.
[email protected]
China
Thorlabs China
[email protected]

www.thorlabs.com