THORLABS PDA10D2 User manual

PDA10D2
Extended InGaAs
Amplified Fixed Gain
Detector
User Guide

Extended InGaAs Amplified Fixed Gain Detector
Table of Contents
Chapter 1 Warning Symbol Definitions ...........................................1
Chapter 2 Description........................................................................2
Chapter 3 Setup..................................................................................3
Chapter 4 Operation...........................................................................4
4.1. Theory of Operation......................................................4
4.2. Responsivity .................................................................4
4.3. Dark Current .................................................................4
4.4. Bandwidth and Response ..............................................5
4.5. Terminating Resistance.................................................5
Chapter 5 Troubleshooting...............................................................6
Chapter 6 Specifications...................................................................7
6.1. Response Curve.............................................................9
6.2. Mechanical Drawing ...................................................10
Chapter 7 Certificate of Conformance...........................................11
Chapter 8 Regulatory.......................................................................12
Chapter 9 Thorlabs Worldwide Contacts.......................................13

Extended InGaAs Amplified Fixed Gain Detector Chapter 1: Warning Symbol Definitions
Rev B, January 3, 2019 Page 1
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: ESD Sensitive Components

Extended InGaAs Amplified Fixed Gain Detector Chapter 2: Description
Page 2 TTN135165-D02
Chapter 2 Description
The PDA10D2 is an amplified, Indium Gallium Arsenide (InGaAs) detector
designed for detection of light ranging from 900 to 2600 nm. A buffered output
drives 50 Ωload impedances up to 5 V. The PDA10D2 housing includes a
removable threaded coupler (SM1T1) and retainer ring (SM1RR) that is
compatible with any number of Thorlabs 1" threaded accessories. This allows
convenient mounting of external optics, light filters, apertures, as well as
providing an easy mounting mechanism using Thorlabs’cage assembly
accessories.
ESD Caution
The components inside this instrument are ESD sensitive. Take all
appropriate precautions to discharge personnel and equipment before
making any electrical connections to the unit.

Extended InGaAs Amplified Fixed Gain Detector Chapter 3: Setup
Rev B, January 3, 2019 Page 3
Chapter 3 Setup
The detector can be set up in many different ways using our extensive line of
adapters. However, the detector should always be mounted and secured for best
operation.
1. Unpack the optical head, install either an imperial or metric optical post
into one of the mounting holes located on the bottom and side of the
sensor, and mount using a post holder. Note that these detectors
feature tapped holes that accept both 8-32 and M4 threads, so using
either imperial or metric TR posts is possible.
2. Connect the power supply 3-pin plug into the power receptacle on the
PDA10D2.
3. Plug the power supply into a 50 to 60 Hz, 100 V / 120 V / 230 V power
outlet.
4. Attach a 50 Ωcoax cable (i.e. RG-58U) 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 p/n T4119) 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 Ω
which could allow ~135 mA of output current. This will damage the
output driver of the PDA10D2.
5. Power the PDA10D2 on using the power switch located on the top side
of the unit.
Caution!
The PDA10D2 was designed to allow maximum accessibility to the
photodetector by having the active area 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.
6. Install any desired filters, optics, adapters, or fiber adapters to the input
aperture.
7. During alignment, take appropriate precautions, such as using reduced
radiation power, or other precautions, and use proper eye and/or skin
protection as recommended by the radiation source manufacturer.
8. Apply a light source to the detector.

Extended InGaAs Amplified Fixed Gain Detector Chapter 4: Operation
Page 4 TTN135165-D02
Chapter 4 Operation
4.1. Theory of Operation
Thorlabs PDA series are ideal for measuring both pulsed and CW light sources.
The PDA10D2 includes a reverse-biased PIN photo diode, mated to a fixed gain
transimpedance amplifier, and packaged in a rugged housing.
4.2. Responsivity
The responsivity of a photodiode can be defined as a ratio of generated
photocurrent (IPD) to the incident light power (P) at a given wavelength:
󰇛󰇜

4.3. Dark Current
Dark current is leakage current which flows when a bias voltage is applied to a
photodiode. The PDA with Transimpedance Amplifier does control the dark
current flowing out. Looking at the figure above, it can be noted that Point B is
held at ground and the amplifier will try to hold point A to “Virtual Ground”. This
minimizes the effects of dark current present in the system.
The dark current present is also affected by the photodiode material and the size
of the active area. Silicon devices generally produce low dark current compared
to germanium devices which have high dark currents. The table below lists
several photodiode materials and their relative dark currents, speeds, sensitivity,
and costs. Please note that sensitivity values in the table are typical values;
Thorlabs offers photodetectors with sensitivity ranges that vary from those shown
below.

Extended InGaAs Amplified Fixed Gain Detector Chapter 4: Operation
Rev B, January 3, 2019 Page 5
Material
Dark
Current
Speed
Sensitivity1
(nm)
Cost
Silicon (Si)
Low
High
400 –1000
Low
Germanium (Ge)
High
Low
900 –1600
Low
Gallium Phosphide (GaP)
Low
High
150 –550
Med
Indium Gallium Arsenide
(InGaAs)
Low
High
800 –1800
Med
Extended Range: Indium
Gallium Arsenide (InGaAs)
High
High
1200 –2600
High
4.4. Bandwidth and Response
For the PDA detectors, the gain of the detector is dependent on the feedback
element (Rf). The bandwidth of the detector can be calculated using the
following:
󰇛󰇜

Where GBP is the amplifier gain bandwidth product and CDis the sum of the
photodiode junction capacitance and the amplifier capacitance.
4.5. Terminating Resistance
The maximum output of the PDA10A2 is 10 V for high impedance loads (i.e.
RLoad > 5 kΩ) and 5 V for 50 Ω loads. Adjust the gain so that the measured signal
level out of the PDA10A2 is below 10 V (5 V with a 50 Ω load) to avoid
saturation.
For low terminating resistors, <5 kΩ or 1% error, an additional factor needs to be
considered. The output of the PDA includes a 50 Ω series resistor (Rs). The
output load creates a voltage divider with the 50 Ω series resistor as follows:
 

 
󰇛󰇜󰇛󰇜
Note that we already include the scale factor in our specification for the gain at
50 Ω. Refer to the table in Chapter 6 for additional performance specifications.
1
Approximate values; actual wavelength values will vary.

Extended InGaAs Amplified Fixed Gain Detector Chapter 5: Troubleshooting
Page 6 TTN135165-D02
Chapter 5 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.
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
coulpler (SM1T1) to baffle any external light
sources to see if this improves the response.

Extended InGaAs Amplified Fixed Gain Detector Chapter 6: Specifications
Rev B, January 3, 2019 Page 7
Chapter 6 Specifications
All performance specifications are typical, performed at 25 °C ambient
temperature, and assume a 50 Ω load, unless stated otherwise.
2
The PDA10D2 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 Ω load divides signal in half).
Electrical Specifications2
Detector
-
InGaAs
Active Area
-
Ø1.0 mm (0.8 mm2)
Wavelength Range
λ
900 to 2600 nm
Peak Wavelength
λp
2300 nm (Typ.)
Peak Response
( λ p)
1.35 A/W (Typ.)
Small Signal Bandwidth
-
25 MHz
NEP (λp)
W/√Hz
1.01 x 10-11
Noise (RMS)
-
2.5 mVrms
Max Ouput Current
IOUT
100 mA
Dark Offset
-
±75 mV (Typ.)
±375 mV (Max)
Load Impedance
-
50 Ωto Hi-Z
Transimpedance Gain
-
5 x 103V/A (50 Ω)
1 x 104V/A (Hi-Z)
Output Voltage
VOUT
0 to 5 V (50 Ω)
0 to 10 V (Hi-Z)

Extended InGaAs Amplified Fixed Gain Detector Chapter 6: Specifications
Page 8 TTN135165-D02
3
Measured from the active area to the start of the threads on the housing body. The detector
active area surface is flush with the front of the housing body.
4
Although the power supply is rated for 6 W, this detector’s actual usage is <5 W over the full
operating range.
General
On/Off Switch
Slide
Output
BNC (DC Coupled)
Package Size
2.79" x 1.96" x 0.89"
(70.9 mm x 49.8 mm x 22.5 mm)
PD Surface Depth3
0.09" (2.2 mm)
Weight, Detector Only
0.10 kg
Accessories
SM1T1 Coupler
SM1RR Retainer Ring
Operating Temp
10 to 50 °C
Storage Temp
-25 to 70 °C
AC Power Supply
AC –DC Converter
Input Power4
6 W
100 V / 120 V / 230 V, 50 –60 Hz