Free-Space Si Avalanche Photodetectors

High-Speed Response Up to 1 GHz
Conversion Gains up to 2.65 × 10⁹ V/W
Wavelength Range of 200 - 1000 nm or 400 - 1000 nm
Temperature-Compensated and Variable-Gain Versions Available

APD210

High-Speed APD

APD130A2

Temperature-Compensated APD

APD430A

Variable-Gain,
Temperature-Compensated APD

Hide Overview

OVERVIEW

Free-Space Si APD Selection Guide
Item #	Wavelength Range	Bandwidth (3 dB)	Type (Quick Links)
APD130A2(/M)	200 - 1000 nm	DC - 50 MHz	Temperature Compensated
APD130A(/M)	400 - 1000 nm	DC - 50 MHz	Temperature Compensated
APD440A2	200 - 1000 nm	DC - 0.1 MHz	Variable Gain, Temperature Compensated
APD410A2(/M)		DC - 10 MHz
APD430A2(/M)		DC - 400 MHz
APD440A	400 - 1000 nm	DC - 0.1 MHz
APD410A(/M)		DC - 10 MHz
APD430A(/M)		DC - 400 MHz
APD410	200 - 1000 nm	5 - 900 MHz	Variable Gain, Temperature Compensated, High Speed
APD210	400 - 1000 nm	5 - 1000 MHz	Variable Gain, Temperature Compensated, High Speed

Click to Enlarge
The above plot shows the M factor stability of our temperature-compensated avalanche photodetectors. The blue shaded region indicates the temperature range over which the M factor stability is guaranteed to within ±3%.

Features

Noise Equivalent Powers (NEP) as Low as 2.5 fW/√Hz
Max Bandwidth Up to 1 GHz at 3 dB
Temperature-Compensated Versions Provide M Factor Stability of ≤±3% Over 18 to 28 °C
Variable Gain Detectors Available: M Factor from 5 to 50 or 10 to 100
Free-Space Optical Input with Internal SM05 and External SM1 Threading for Lens Tubes
Power Supply Included

Thorlabs' Free-Space Silicon Avalanche Photodetectors (APD) are designed to offer increased sensitivity and lower noise compared to standard PIN detectors, making them ideal for applications with low optical power levels. In addition to our standard APDs, versions featuring variable gain (i.e., M factor) and/or temperature compensation are offered.

In general, avalanche photodiodes use an internal gain mechanism to increase sensitivity. A high reverse bias voltage is applied to the diodes to create a strong electric field. When an incident photon generates an electron-hole pair, the electric field accelerates the electrons, leading to the production of secondary electrons by impact ionization. The resulting electron avalanche can produce a gain factor of several hundred times, described by a multiplication factor, M, that is a function of both the reverse bias voltage and temperature. In general, the M factor increases with lower temperatures and decreases with higher temperatures. Similarly, the M factor will increase when the reverse bias voltage is raised and decrease when the reverse bias voltage is lowered.

Our APD130A2(/M) and APD130A(/M) temperature-compensated APDs feature integrated thermistors that adjust the bias voltage to compensate for the effect of temperature changes on the M factor. A comparison with our non-temperature-compensated APDs is provided in the graph to the right.

In addition to being temperature compensated, our variable-gain APD400 series detectors allow the reverse bias voltage across the diodes to be adjusted via a rotary knob on the side of the housing, which varies the M factor from 5 to 50 or 10 to 100.

Thorlabs offers Menlo Systems' APD410 and APD210 Variable-Gain Avalanche Photodetectors, which offer high-speed responses up to 900 MHz or 1 GHz at 3 dB, respectively. Additionally, we offer spectral-flattening filters that are designed to improve the response uniformity of our silicon photodiodes and detectors; click here to learn more.

A complete list of all of our APDs can be found on the Selection Guide tab. Please note that our Single Photon Detectors are the only avalanche photodetectors suitable for single photon counting.

Avalanche Photodiode Selection Guide^a
Free-Space Si APDs
Fiber-Coupled Si APDs
Free-Space InGaAs APDs
Fiber-Coupled InGaAs APDs

Please see the Selection Guide tab for a complete list of all of our avalanche photodetectors.

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SPECS

Click on the yellow boxes below to view specifications for each type of photodetector.

Temperature-Compensated Si Avalanche Photodetectors

All technical data are valid at 23 ± 5 °C and 45% ± 15% relative humidity (non-condensing).

Item #	APD130A2(/M)	APD130A(/M)
Detector Type	UV Enhanced Silicon APD	Silicon APD
Wavelength Range	200 - 1000 nm	400 - 1000 nm
Output Bandwidth (3 dB)	DC - 50 MHz
Active Area Diameter	1 mm
Typical Max Responsivity	25 A/W @ 600 nm (M = 50)	25 A/W @ 800 nm (M = 50)
M Factor^a,b	50
M Factor Temperature Stability^c	±2% (Typical); ±3% (Max)	±2% (Typical); ±3% (Max)
Transimpedance Gain	50 kV/A with 50 Ω Termination^d100 kV/A for High-Impedance Termination
Max Conversion Gain^e,f	2.5 x 10⁶ V/W
CW Saturation Power	1.5 µW
Max Input Power^g	1 mW
Minimum NEP (DC - 50 MHz)^e,h	0.21 pW/√Hz	0.20 pW/√Hz
Integrated Noise (DC - 50 MHz)	1.4 nW (RMS)	1.5 nW (RMS)
Electrical Outputs	50 Ω BNC
Max Output Voltage	1.8 V with 50 Ω Termination 3.6 V with High-Impedance Termination
DC Offset Electrical Output	<±15 mV
Power Supplyⁱ	±12 V @ 250 mA (100/120/230 VAC, 50 - 60 Hz, Switchable)
General
Operating Temperature Range	0 to 40 °C (Non-Condensing)
Storage Temperature Range	-40 to 70 °C
Device Dimensions (H x W x D)	75.5 mm x 50.8 mm x 27.4 mm (2.97" x 2.00" x 1.08")
Weight	<0.1 kg

These detectors are factory set to M = 50, but other M factors are available on request. Please contact techsupport@thorlabs.com for more information.
The responsivity scales with the M factor, which is dependent on the reverse bias voltage across the photodiode. For a given photodiode, a higher M factor corresponds to a higher reverse bias voltage, which increases the photodiode responsivity. By definition, M = 1 corresponds to a reverse bias voltage of 0 V.
Temperature within 23 ± 5 °C.
50 Ω termination is recommended for the best performance.
At the Peak Responsivity Wavelength
The Conversion Gain is product of the Transimpedance Gain and the Responsivity for a given M factor and wavelength.
This value is the damage threshold for the photodiode.
For more information on how NEP is calculated, please see Thorlabs' Noise Equivalent Power White Paper.
A replacement power supply is available below.

APD120A, APD120A2, APD130A & APD130A2 Responsivity

Click to Enlarge

Variable-Gain, Temperature-Compensated Si Avalanche Photodetectors

All technical data are valid at 23 ± 5 °C and 45% ± 15% relative humidity (non-condensing).

Item #	APD440A2	APD410A2(/M)	APD430A2(/M)
Detector Type	UV Enhanced Silicon APD
Wavelength Range	200 - 1000 nm
Output Bandwidth (3 dB)^a	DC - 100 kHz	DC - 10 MHz	DC - 400 MHz
Active Area Diameter	1.0 mm	0.5 mm	0.2 mm
Typical Max Responsivity	25 A/W @ 600 nm (M = 50)	25 A/W @ 600 nm (M = 50)	50 A/W @ 600 nm (M = 100)
Responsivity Graph (Click to View)
M Factor Adjustment Range^b,c	5 - 50 (Continuous)		10 - 100 (Continuous)
M Factor Temperature Stability^d	±2% (Typical); ±3% (Max)
Transimpedance Gain	25 MV/A (50 Ω Termination) 50 MV/A (High-Z Termination)	250 kV/A (50 Ω Termination)^e 500 kV/A (High-Z Termination)	5 kV/A (50 Ω Termination)^e 10 kV/A (High-Z Termination)
Max Conversion Gain^f,g	1.25 × 10⁹ V/W	12.5 × 10⁶ V/W	5.0 × 10⁵ V/W
CW Saturation Power	3.28 nW @ 600 nm, M = 50 32.8 nW @ 600 nm, M = 5	0.32 µW @ 600 nm, M = 50 3.20 µW @ 600 nm, M = 5	8.0 µW @ 600 nm, M = 100 80 µW @ 600 nm, M = 10
Max Input Power^h	1 mW
Minimum NEPⁱ	2.5 fW/√Hz (DC - 100 kHz)	0.09 pW/√Hz (DC - 10 MHz)	0.15 pW/√Hz (DC - 100 MHz)
Integrated Noise (RMS)^a	0.8 pW (DC - 100 kHz)	0.28 nW (DC - 10 MHz)	6 nW (DC - 400 MHz)
Electrical Outputs	50 Ω BNC
Max Output Voltage	2.0 V (50 Ω Termination); 4.1 V (High-Z Termination)
DC Offset Electrical Output	<±3 mV
Included Power Supply^j	±12 V @ 250 mA (100/120/230 VAC, 50 - 60 Hz, Switchable)
General
Operating Temperature Range	0 to 40 °C (Non-Condensing)
Storage Temperature Range	-40 to 70 °C
Device Dimensions (H x W x D)	2.93" x 2.21" x 1.08" (74.5 mm x 56.1 mm x 27.4 mm)	2.97" x 2.20" x 1.09" (75.5 mm x 55.8 mm x 27.6 mm)
Weight	0.12 kg	0.1 kg

At Maximum Gain Setting
The responsivity scales with the M factor, which is dependent on the reverse bias voltage across the photodiode. For a given photodiode, a higher M factor corresponds to a higher reverse bias voltage, which increases the photodiode responsivity. By definition, M = 1 corresponds to a reverse bias voltage of 0 V.
For Small Signals
Ambient temperature within 23 ± 5 °C.
50 Ω termination is recommended for the best performance.
At the Peak Responsivity Wavelength
The conversion gain is the product of the transimpedance gain and the responsivity for a given M factor and wavelength.
This value is the damage threshold for the photodiode.
For more information on how NEP is calculated, please see Thorlabs' Noise Equivalent Power White Paper.
A replacement power supply is available below.

Item #	APD440A	APD410A	APD430A
Detector Type	Silicon APD
Wavelength Range	400 - 1000 nm
Output Bandwidth (3 dB)^a	DC - 100 kHz	DC - 10 MHz	DC - 400 MHz
Active Area Diameter	1.0 mm	1.0 mm	0.5 mm
Typical Max Responsivity	53 A/W @ 800 nm (M = 100)
Responsivity Graph (Click to View)
M Factor Adjustment Range^b	10 - 100 (Continuous)
M Factor Temperature Stability^c	±2% (Typical); ±3% (Max)
Transimpedance Gain	25 MV/A (50 Ω Termination) 50 MV/A (High-Z Termination)	250 kV/A (50 Ω Termination)^d 500 kV/A (High-Z Termination)	5 kV/A (50 Ω Termination)^d 10 kV/A (High-Z Termination)
Max Conversion Gain^e,f	2.65 × 10⁹ V/W	26.5 × 10⁶ V/W	5.3 × 10⁵ V/W
CW Saturation Power	1.54 nW @ 800 nm, M = 100 15.4 nW @ 800 nm, M = 10	0.15 µW @ 800 nm, M = 100 1.50 µW @ 800 nm, M = 10	8.0 µW @ 800 nm, M = 100 80 µW @ 800 nm, M = 10
Max Input Power^g	1 mW
Minimum NEP^f,g	3.5 fW/√Hz (DC - 100 kHz)	0.04 pW/√Hz (DC - 10 MHz)	0.14 pW/√Hz (DC - 100 MHz)
Integrated Noise (RMS)^a	1.1 pW (DC - 100 kHz)	0.13 nW (DC - 10 MHz)	5.5 nW (DC - 400 MHz)
Electrical Outputs	50 Ω BNC
Max Output Voltage	2.0 V (50 Ω Termination); 4.1 V (High-Z Termination)
DC Offset Electrical Output	<±3 mV
Included Power Supplyⁱ	±12 V @ 250 mA (100/120/230 VAC, 50 - 60 Hz, Switchable)
General
Operating Temperature Range	0 to 40 °C (Non-Condensing)
Storage Temperature Range	-40 to 70 °C
Device Dimensions (H x W x D)	2.93" x 2.21" x 1.08" (74.5 mm x 56.1 mm x 27.4 mm)	2.97" x 2.20" x 1.09" (75.5 mm x 55.8 mm x 27.6 mm)
Weight	0.12 kg	0.1 kg

At Maximum Gain Setting
The responsivity scales with the M factor, which is dependent on the reverse bias voltage across the photodiode. For a given photodiode, a higher M factor corresponds to a higher reverse bias voltage, which increases the photodiode responsivity. By definition, M = 1 corresponds to a reverse bias voltage of 0 V.
Ambient temperature within 23 ± 5 °C.
50 Ω termination is recommended for the best performance.
At the Peak Responsivity Wavelength
The conversion gain is the product of the transimpedance gain and the responsivity for a given M factor and wavelength.
This value is the damage threshold for the photodiode.
For more information on how NEP is calculated, please see Thorlabs' Noise Equivalent Power White Paper.
A replacement power supply is available below.

Variable-Gain, Temperature-Compensated, High-Speed Si Avalanche Photodetectors

Item #	APD410	APD210
Detector Type	Si APD
Optical Input	Free Space^a
Wavelength Range	200 - 1000 nm	400 - 1000 nm
Damage Threshold	10 mW	10 mW
Active Area Diameter	0.2 mm	0.5 mm
Frequency Range	1 MHz - 1600 MHz
3 dB Bandwidth	5 MHz - 900 MHz	5 MHz - 1000 MHz
Rise Time	500 ps	500 ps
Conversion Gain (Max)^b	4.5 x 10⁴ V/W @ 650 nm	2.5 x 10⁵ V/W @ 800 nm
NEP (Calculated)^c	87.6 pW/√Hz	0.24 pW/√Hz
Dark State Noise Level^d	-80 dBm
M Factor	50	100
Typical Max Responsivity	22 A/W @ 650 nm	50 A/W @ 800 nm
Output Impedance	50 Ω
Output Connector	BNC
Output Coupling	AC
Current Consumption (Max)	200 mA
Supply Voltage^e	+12 to +15 V
Operating Temperature	10 to 40 °C
Storage Temperature	-20 to +85 °C
Storage Humidity	10% - 90% RH
Device Dimensions	60 mm x 50 mm x 47.5 mm (2.36" x 1.97" x 1.87")

Aperture Includes Internal SM05 (0.535"-40) Threading
Gain Adjustable via Push Buttons
The noise-equivalent power is a measure of the detector's minimum detectable power per square root of bandwidth. Since this value only depends on the detector itself, it can be used to compare two detectors that do not have the same integration time. The smaller the NEP value, the better the detector.
This is a measure of the noise when no light is incident on the detector's photosensitive area. Span: 5 MHz, Resolution Bandwidth: 3 kHz
A power supply is included with a US or EU adapter, depending on your location. Please contact Tech Support if a different adapter is required.

Performance Graphs (Click to View)
Item #	APD410	APD210
Responsivity
Frequency Response
Time Characteristics
Rise Time

Hide Pin Diagrams

PIN DIAGRAMS

BNC Female Output (Photodetector)

APD Male (Power Cables)

APD Female (Photodetector)

Pinout for PDA Power Connector

Hide Fiber Coupling

FIBER COUPLING&NBSP;

Components for Fiber Coupling^a
Item #	Description
-	Free-Space Avalanche Photodetector
LM1XY(/M)	Translating Lens Mount for Ø1" Optics
SM1L10	SM1 (1.035"-40) Lens Tube, 1" Long
-	Fiber Collimator (Dependent on Fiber)
AD11F or AD12F	SM1-Threaded Adapters for Ø11 or Ø12 mm Fiber Collimators (Dependent on Collimator)
-	Mounted Molded Aspheric Lens (Dependent on Collimator)
S1TM06, S1TM08, S1TM09, S1TM10, or S1TM12	SM1-Threaded Adapter for Molded Aspheric Lens Cell (Dependent on Lens)

This describes the construction of a fiber coupling mechanism for our Si free-space avalanche photodetectors. For direct fiber coupling, please see our Si Fiber-Coupled Avalanche Photodetector.

Click to Enlarge
Output from a fiber is coupled into the photodetector using an aspheric lens to focus the signal onto the detector active area.

Fiber Coupling to Free-Space APDs

A fiber coupling mechanism can be constructed for our free-space APDs using standard optomechanics. In fiber coupling applications, we recommend taking into account the divergence of light from the fiber tip to ensure that all of the signal is focused onto the detector active area. When using a standard fiber connector adapter with a detector with an active area smaller than Ø1 mm, high coupling losses and degradation of the frequency response may occur.

To achieve high coupling efficiency, a fiber collimation package, focusing lens, and X-Y translator should be used, as shown in the photo to the right. The avalanche photodetector is shown with a fiber collimator, lens tube collimator adapter, lens tube, and X-Y translation mount. An adapter inside the lens tube holds an aspheric lens (not visible) to focus the collimated light onto the active area of the detector. The X-Y translation mount corrects for any centering issues.

Please note that Thorlabs also offers the APD431A fiber-coupled Si photodetector, which features an M12 x 0.15-threaded flange that is directly compatible with our M12 x 0.5-threaded fiber connector adapters. This compact and robust mechanism allows for easy fiber coupling with high reproducbility. The M12 x 0.5-threaded flange can be added to any of Thorlabs' Avalanche Photodetectors to provide robust fiber-coupling capabilities. Please contact Tech Support for more information.

Hide Pulse Calculations

PULSE CALCULATIONS

Pulsed Laser Emission: Power and Energy Calculations

Click above to download the full report.

Determining whether emission from a pulsed laser is compatible with a device or application can require referencing parameters that are not supplied by the laser's manufacturer. When this is the case, the necessary parameters can typically be calculated from the available information. Calculating peak pulse power, average power, pulse energy, and related parameters can be necessary to achieve desired outcomes including:

Protecting biological samples from harm.
Measuring the pulsed laser emission without damaging photodetectors and other sensors.
Exciting fluorescence and non-linear effects in materials.

Pulsed laser radiation parameters are illustrated in Figure 1 and described in the table. For quick reference, a list of equations are provided below. The document available for download provides this information, as well as an introduction to pulsed laser emission, an overview of relationships among the different parameters, and guidance for applying the calculations.

Equations:
Period and repetition rate are reciprocal:		and
Pulse energy calculated from average power:
Average power calculated from pulse energy:
Peak pulse power estimated from pulse energy:
Peak power and average power calculated from each other:
	and
Peak power calculated from average power and duty cycle*:
	*Duty cycle () is the fraction of time during which there is laser pulse emission.

Click to Enlarge

Figure 1: Parameters used to describe pulsed laser emission are indicated in the plot (above) and described in the table (below). Pulse energy (E) is the shaded area under the pulse curve. Pulse energy is, equivalently, the area of the diagonally hashed region.

Parameter	Symbol	Units
Pulse Energy	E	Joules [J]	A measure of one pulse's total emission, which is the only light emitted by the laser over the entire period. The pulse energy equals the shaded area, which is equivalent to the area covered by diagonal hash marks.
Period	Δt	Seconds [s]	The amount of time between the start of one pulse and the start of the next.
Average Power	P_avg	Watts [W]	The height on the optical power axis, if the energy emitted by the pulse were uniformly spread over the entire period.
Instantaneous Power	P	Watts [W]	The optical power at a single, specific point in time.
Peak Power	P_peak	Watts [W]	The maximum instantaneous optical power output by the laser.
Pulse Width		Seconds [s]	A measure of the time between the beginning and end of the pulse, typically based on the full width half maximum (FWHM) of the pulse shape. Also called pulse duration.
Repetition Rate	f_rep	Hertz [Hz]	The frequency with which pulses are emitted. Equal to the reciprocal of the period.

Example Calculation:

Is it safe to use a detector with a specified maximum peak optical input power of 75 mW to measure the following pulsed laser emission?

Average Power: 1 mW
Repetition Rate: 85 MHz
Pulse Width: 10 fs

The energy per pulse:

seems low, but the peak pulse power is:

It is not safe to use the detector to measure this pulsed laser emission, since the peak power of the pulses is >5 orders of magnitude higher than the detector's maximum peak optical input power.

Hide Selection Guide

SELECTION GUIDE

Avalanche Photodetector Selection Guide

Item #	Detector Type	Wavelength Range	3 dB Bandwidth	Active Area Diameter	M Factor	Typical Max Responsivity	Max Conversion Gain^a	Variable Gain	Fiber-Coupled^b
APD440A2	UV Enhanced Silicon APD	200 - 1000 nm	DC - 0.1 MHz	1 mm	5 - 50	25 A/W @ 600 nm (M = 50)	1.25 x 10⁹ V/W		-
APD410A2			DC - 10 MHz	0.5 mm	5 - 50	25 A/W @ 600 nm (M = 50)	12.5 x 10⁶ V/W		-
APD130A2			DC - 50 MHz	1 mm	50	25 A/W @ 600 nm (M = 50)	2.5 x 10⁶ V/W	-	-
APD430A2			DC - 400 MHz	0.2 mm	10 - 100	50 A/W @ 600 nm (M = 100)	5.0 x 10⁵ V/W		-
APD410			5 - 900 MHz^c	0.2 mm	50	22 A/W @ 650 nm (M = 50)	4.5 x 10⁴ V/W^d		-
APD440A	Silicon APD	400 - 1000 nm	DC - 0.1 MHz	1 mm	10 - 100	53 A/W @ 800 nm (M = 100)	2.65 x 10⁹ V/W		-
APD410A			DC - 10 MHz	1.0 mm	10 - 100	53 A/W @ 800 nm (M=100)	26.5 x 10⁶ V/W		-
APD130A			DC - 50 MHz	1 mm	50	25 A/W @ 800 nm (M = 50)	2.5 x 10⁶ V/W	-	-
APD430A			DC - 400 MHz	0.5 mm	10 - 100	53 A/W @ 800 nm (M = 100)	5.3 x 10⁵ V/W		-
APD431A			DC - 400 MHz^e	0.5 mm	10 - 100	53 A/W @ 800 nm (M = 100)	5.3 x 105 V/W
APD210			5 - 1000 MHz^c	0.5 mm	100	50 A/W @ 800 nm (M = 100)	2.5 x 10⁵ V/W^f		-
APD130C	InGaAs APD	900 - 1700 nm	DC - 50 MHz	0.2 mm	10	9 A/W @ 1500 nm (M = 10)	0.9 x 10⁶ V/W	-	-
APD410C			DC - 10 MHz	0.2 mm	4 - 20	18 A/W @ 1550 nm (M = 20)	9.0 x 10⁶ V/W		-
APD430C			DC - 400 MHz	0.2 mm	4 - 20	18 A/W @ 1550 nm (M = 20)	1.8 x 10⁵ V/W		-
APD431C			DC - 400 MHz^e	0.2 mm	4 - 20	18 A/W @ 1550 nm (M = 20)	1.8 x 10⁵ V/W
APD450C		1260 - 1620 nm	0.3 - 1600 MHz	1.5 mm^g	2 - 10	9 A/W @ 1550 nm (M = 10)	45 × 10³ V/W		-
APD310		850 - 1650 nm	5 - 1000 MHz^c	0.04 mm	30	0.9 A/W @ 1550 nm (M = 30)	2.5 x 10⁴ V/W^h		-

At Peak Responsivity Wavelength Unless Otherwise Stated
Fiber-coupled APDs have an external M12 x 0.5-threaded flange that is directly compatible with our APD fiber connector adapters. This M12 x 0.5-threaded flange can be added to any of Thorlabs' Avalanche Photodetectors. Please contact Tech Support for more information.
The max frequency range is 1 MHz - 1600 MHz.
At 1 GHz and 650 nm
At Maximum Gain Setting
At 1 GHz and 800 nm
75 µm Detector with Ø1.5 mm Ball Lens
At 1 GHz and 1500 nm

Hide Temperature-Compensated Si Avalanche Photodetectors

Temperature-Compensated Si Avalanche Photodetectors

Key Specifications^a
Item #	APD130A2(/M)	APD130A(/M)
Detector Type	UV-Enhanced Silicon APD	Silicon APD
Wavelength Range	200 - 1000 nm	400 - 1000 nm
Output Bandwidth (3 dB)	DC - 50 MHz
Active Area Diameter	1 mm
Typical Max Responsivity (M = 50)	25 A/W @ 600 nm	25 A/W @ 800 nm
Responsivity Graph (Click to View)
Transimpedance Gain	50 kV/A (50 Ω Termination) 100 kV/A (High-Z Termination)
Max Conversion Gain^b	2.5 × 10⁶ V/W
M Factor	50
M Factor Temperature Stability^a	±2% (Typical); ±3% (Max)
Saturation Power (CW)	1.5 µW
Minimum NEP (DC - 50 MHz)^b	0.21 pW/√Hz	0.20 pW/√Hz
Dimensions (H x W x D)	2.97" x 2.00" x 1.08"

For a complete list of specifications and responsivity graphs, please see the Specs tab above. Data are valid at 23 ± 5 °C and 45% ± 15% relative humidity (non-condensing).
At the Peak Responsivity Wavelength. For more information on how NEP is calculated, please see Thorlabs' Noise Equivalent Power White Paper.

Temperature Compensated to Provide M Factor Stability of ≤±3% Over 18 to 28 °C
Internal SM05 and External SM1 Threads Accept Most Fiber Adapters, Lens Tubes, and Other Components
Power Supply Included

Thorlabs' APD130A2(/M) and APD130A(/M) Free-Space Avalanche Photodetectors feature an integrated thermistor that maintains an M factor stability of ±3% or better over 23 ± 5 °C by adjusting the bias voltage across the avalanche photodiode, supplying improved output stability in environments with temperature variations.

The orientation of the mechanical and electrical connections, combined with the compact design, ensures that these detectors can fit into tight spaces. Three 8-32 (M4) mounting holes, one on each edge of the housing, further ensure easy integration into complicated mechanical setups. The housing also provides compatibility with both our SM05- and SM1-Series Lens Tubes. An internally SM1-threaded cap is included.

Our SM1-threaded fiber adapters are compatible with these detectors. The internally SM1-threaded adapters can be mated directly to the housing, and are available below. To use our externally SM1-threaded fiber adapters, an internally SM1-threaded lens tube will be required to mate the fiber adapter to the detector's housing. The externally SM05-threaded fiber adapters are not compatible with these detectors.

Part Number	Description	Price	Availability
APD130A2/M	Si Avalanche Photodetector, Temperature Compensated, UV Enhanced, 200 - 1000 nm, M4 Taps	$1,397.00	Today
APD130A/M	Si Avalanche Photodetector, Temperature Compensated, 400 - 1000 nm, M4 Taps	$1,397.00	Today
APD130A2	Si Avalanche Photodetector, Temperature Compensated, UV Enhanced, 200 - 1000 nm, 8-32 Taps	$1,397.00	Today
APD130A	Si Avalanche Photodetector, Temperature Compensated, 400 - 1000 nm, 8-32 Taps	$1,397.00	Today

Hide Variable-Gain, Temperature-Compensated Si Avalanche Photodetectors

Variable-Gain, Temperature-Compensated Si Avalanche Photodetectors

Click to Enlarge
The M Factor is controlled by a knob on the side of the APD.

Continuously Variable Gain
Temperature Compensated to Provide M Factor Stability of ≤±3% Over 18 to 28 °C
Internal SM05 and External SM1 Threads Accept Most Fiber Adapters, Lens Tubes, and Other Components
Power Supply Included

These Free-Space Avalanche Photodetectors feature a variable gain that can be controlled by a knob on the right side of the housing. Like the APD130A detectors above, these devices feature an integrated thermistor that maintains an M factor stability of ±3% or better over 23 ± 5 °C by adjusting the bias voltage across the avalanche photodiode. Compared to the standard and temperature-controlled APDs above, the APD430A2 and APD430A detectors also offer a larger usable bandwidth of DC to 400 MHz. The APD410A2 and APD410A detectors offer a slightly smaller usable bandwidth (DC to 10 MHz), but with higher sensitivity. The APD440A2 and APD440A detectors offer high transimpedance gain with a lower max bandwidth of 100 kHz.

Fiber Coupling Note:
A fiber coupling mechanism can be constructed for our free-space APDs using standard optomechanics. For fiber-coupled applications, we do not recommend using fiber connector adapters such as Thorlabs' S120-FC with the APD410A2(/M), APD430A2(/M), and APD430A detectors due to the small size of the sensors. High coupling losses and degradation of the frequency response may occur. To achieve high coupling efficiency, a fiber collimation package, focusing lens, and X-Y translator should be used. See the Fiber Coupling tab for details.

Key Specifications^a
Item #	APD440A2	APD410A2(/M)	APD430A2(/M)	APD440A	APD410A(/M)	APD430A(/M)
Detector Type	UV-Enhanced Silicon APD			Silicon APD
Wavelength Range	200 - 1000 nm			400 - 1000 nm
Output Bandwidth (3 dB)^b	DC - 100 kHz	DC - 10 MHz	DC - 400 MHz	DC - 100 kHz	DC - 10 MHz	DC - 400 MHz
Active Area Diameter	1.0 mm	0.5 mm	0.2 mm	1.0 mm	1.0 mm	0.5 mm
Typical Max Responsivity	25 A/W @ M = 50^c	25 A/W @ M = 50^c	50 A/W @ M = 100^c	53 A/W @ M = 100^d
Responsivity Graph (Click to View)
Transimpedance Gain	25 MV/A (50 Ω) 50 MV/A (High-Z)	250 kV/A (50 Ω) 500 kV/A (High-Z)	5 kV/A (50 Ω) 10 kV/A (High-Z)	25 MV/A (50 Ω) 50 MV/A (High-Z)	250 kV/A (50 Ω) 500 kV/A (High-Z)	5 kV/A (50 Ω) 10 kV/A (High-Z)
Max Conversion Gain^e	1.25 × 10⁹ V/W	12.4 × 10⁶ V/W	5.0 × 10⁵ V/W	2.65 × 10⁹ V/W	26.5 × 10⁶ V/W	5.3 × 10⁵ V/W
M Factor Adjustment Range	5 - 50 (Continuous)		10 - 100 (Continuous)
M Factor Temperature Stability^f	±2% (Typical); ±3% (Max)
Saturation Power (CW)	3.28 nW @ M = 50^c 32.8 nW @ M = 5	0.32 µW @ M = 50^c 3.20 µW @ M = 5	8.0 µW @ M = 100^c 80 µW @ M = 10	1.54 nW @ M = 100^d 15.4 nW @ M = 10	0.15 µW @ M = 100^d 1.50 µW @ M = 10	8.0 µW @ M = 100^d 80 µW @ M = 10
Minimum NEP^g	2.5 fW/√Hz	0.09 pW/√Hz	0.15 pW/√Hz	3.5 fW/√Hz	0.04 pW/√Hz	0.14 pW/√Hz
Dimensions (H x Wx D)	2.93" x 2.21" x 1.08"	2.97" x 2.20" x 1.09"		2.93" x 2.21" x 1.08"	2.97" x 2.20" x 1.09"

For a complete list of specifications and responsivity graphs, please see the Specs tab above. Data are valid at 23 ± 5 °C and 45% ± 15% relative humidity (non-condensing).
At Maximum Gain Setting
At 600 nm
At 800 nm
At the Peak Responsivity Wavelength
Within the 23 ± 5 °C temperature range.
For more information on how NEP is calculated, please see Thorlabs' Noise Equivalent Power White Paper.

Part Number	Description	Price	Availability
APD410A2/M	Si Variable-Gain Avalanche Detector, Temperature Compensated, UV Enhanced, 200 - 1000 nm, DC - 10 MHz, M4 Taps	$1,457.58	Today
APD430A2/M	Si Variable-Gain Avalanche Detector, Temperature Compensated, UV Enhanced, 200 - 1000 nm, DC - 400 MHz, M4 Taps	$1,457.58	Today
APD410A/M	Si Variable-Gain Avalanche Detector, Temperature Compensated, 400 - 1000 nm, DC - 10 MHz, M4 Taps	$1,457.58	7-10 Days
APD430A/M	Si Variable-Gain Avalanche Detector, Temperature Compensated, 400 - 1000 nm, DC - 400 MHz, M4 Taps	$1,457.58	Today
APD440A	Customer Inspired! Si Variable-Gain Avalanche Detector, Temperature Compensated, 400 - 1000 nm, DC - 100 kHz, Universal 8-32 / M4 Taps	$1,300.32	Today
APD440A2	Customer Inspired! Si Variable-Gain Avalanche Detector, Temperature Compensated, 200 - 1000 nm, DC - 100 kHz, Universal 8-32 / M4 Taps	$1,300.32	Today
APD410A2	Si Variable-Gain Avalanche Detector, Temperature Compensated, UV Enhanced, 200 - 1000 nm, DC - 10 MHz, 8-32 Taps	$1,457.58	Today
APD430A2	Si Variable-Gain Avalanche Detector, Temperature Compensated, UV Enhanced, 200 - 1000 nm, DC - 400 MHz, 8-32 Taps	$1,457.58	Today
APD410A	Si Variable-Gain Avalanche Detector, Temperature Compensated, 400 - 1000 nm, DC - 10 MHz, 8-32 Taps	$1,457.58	Today
APD430A	Si Variable-Gain Avalanche Detector, Temperature Compensated, 400 - 1000 nm, DC - 400 MHz, 8-32 Taps	$1,457.58	Today

Hide Variable-Gain, Temperature-Compensated, High-Speed Si Avalanche Photodetectors

Variable-Gain, Temperature-Compensated, High-Speed Si Avalanche Photodetectors

Key Specifications^a
Item #	APD410	APD210
Detector Type	Silicon APD
Wavelength Range	200 - 1000 nm	400 - 1000 nm
Frequency Range	1 - 1600 MHz
3 dB Bandwidth	5 - 900 MHz	5 - 1000 MHz
Active Area Diameter	0.2 mm	0.5 mm
Responsivity Graph (Click to View)
Conversion Gain (Max)	4.5 x 10⁴ V/W @ 1 GHz, 650 nm	2.5 × 10⁵ V/W @ 1 GHz, 800 nm
NEP (Calculated)^b	87.6 pW/√Hz	0.24 pW/√Hz
M Factor	50	100
Typ. Max Responsivity	22 A/W @ 650 nm	50 A/W @ 800 nm

For a complete list of specifications and responsivity graphs, please see the Specs tab above.
For more information on how NEP is calculated, please see Thorlabs' Noise Equivalent Power White Paper.

Applications

Fast Laser Pulses
Ultra-Low-Light Signals

Temperature-Compensated Avalanche Photodiode
Integrated Radio Frequency Amplifier
Continuously Adjustable Gain Setting
Long-Term Field Tested
Free-Space Optical Input with Internal SM05 (0.535"-40) Threading
Easy-to-Use Package
Location-Specific (EU or US) Power Supply Included

Originally developed for the detection of the beat note signal between CW or pulsed lasers, Menlo Systems' Si Avalanche Photodetectors are ideally suited for applications requiring very high sensitivity for low-light input signals in the 200 - 1000 nm or 400 - 1000 nm range. The APD avalanche photodiode series can provide an extremely sensitive alternative to traditional PIN photodiodes. They are also fast enough for the characterization of, for example, pulsed solid-state lasers on the nanosecond time scale.

The detectors maintain high gain stability over the 10 °C to 40 °C temperature range by utilizing a temperature compensation circuit, which adjusts the ~150 V DC bias to ensure operation near the breakdown voltage.

Models for both the visible and near infrared range are available. The compact design of these detectors allows for easy OEM integration.

The units are especially recommended for applications such as metrology when homodyne or heterodyne optical beat signals of weak power have to be detected and amplified in a highly efficient way.

Part Number	Description	Price	Availability
APD410	Si Variable-Gain Avalanche Detector, Temperature Compensated, 200 - 1000 nm, 1 - 1600 MHz, M4 Tap	$2,497.25	Today
APD210	Si Variable-Gain Avalanche Detector, Temperature Compensated, 400 - 1000 nm, 1 - 1600 MHz, M4 Tap	$2,497.25	Today

Hide ±12 VDC Regulated Linear Power Supply

±12 VDC Regulated Linear Power Supply

Replacement Power Supply for Avalanche Photodetectors Sold Above (Except Item # APD210)
±12 VDC Power Output
Current Limit Enabling Short Circuit and Overload Protection
On/Off Switch with LED Indicator
Switchable AC Input Voltage (100, 120, or 230 VAC)
2 m (6.6 ft) Cable with LUMBERG RSMV3 Male Connector
UL and CE Compliant

The LDS12B ±12 VDC Regulated Linear Power Supply is intended as a replacement for the supply included with our APD series of avalanche photodetectors sold on this page, except for the APD210 photodetector. The cord has three pins: one for ground, one for +12 V, and one for -12 V (see diagram above). This power supply ships with a location-specific power cord. This power supply can also be used with the PDA series of amplified photodetectors, PDB series of balanced photodetectors, PMM series of photomultiplier modules, and the FSAC autocorrelator for femtosecond lasers.

Part Number	Description	Price	Availability
LDS12B	±12 VDC Regulated Linear Power Supply, 6 W, 100/120/230 VAC	$93.55	Today

Hide Internally SM1-Threaded Fiber Adapters

Internally SM1-Threaded Fiber Adapters

Internally SM1-Threaded (1.035"-40) Disks with FC/PC, FC/APC, SMA, ST^®*/PC, SC/PC, LC/PC, or Ø2.5 mm Ferrule Receptacle
Light-Tight Construction when used with SM1 Lens Tubes

These Fiber Adapters can be used with many of our avalanche photodetectors above. Note that we do not recommend using fiber connector adapters alone to couple light onto the APD401A2(/M), APD430A2(/M), and APD430A(/M) avalanche photodetectors due to the small size of their sensors. To achieve high coupling efficiency, a fiber collimation package, focusing lens, and X-Y translator should be used. See the Fiber Coupling tab for details.

The FC/PC and FC/APC adapters are available in narrow or wide key versions; for details on narrow versus wide key connectors, please see our Intro to Fiber tutorial.

The FC/APC adapters have two dimples in the front surface that allow them to be tightened with the SPW909 or SPW801 spanner wrench. The dimples do not go all the way through the disk so that the adapter can be used in light-tight applications when paired with SM1 lens tubes.

The S120-25 ferrule adapter is designed without a locking connector mechanism and accepts fiber patch cables with Ø2.5 mm ferrules for quick measurements with photodetectors or power sensors.

Item #	S120-FC2	S120-FC	S120-APC2^a	S120-APC^a	S120-SMA	S120-ST	S120-SC	S120-LC	S120-25
Adapter Image (Click the Image to Enlarge)
Fiber Connector Type	FC/PC, 2.0 mm Narrow Key	FC/PC, 2.2 mm Wide Key	FC/APC, 2.0 mm Narrow Key	FC/APC 2.2 mm Wide Key	SMA	ST/PC	SC/PC^b	LC/PC	Ø2.5 mm Ferrule
Threading	Internal SM1 (1.035"-40)

The S120-APC2 and S120-APC are designed with a 4° mechanical angle to compensate for the refraction angle of the output beam.
In certain angle-independent applications, this adapter may also be used with SC/APC connectors.

*ST^® is a registered trademark of Lucent Technologies, Inc.

Part Number	Description	Price	Availability
S120-FC2	FC/PC Fiber Adapter Cap with Internal SM1 (1.035"-40) Threads, Narrow Key (2.0 mm)	$46.33	Today
S120-FC	FC/PC Fiber Adapter Cap with Internal SM1 (1.035"-40) Threads, Wide Key (2.2 mm)	$46.33	Today
S120-APC2	FC/APC Fiber Adapter Cap with Internal SM1 (1.035"-40) Threads, Narrow Key (2.0 mm)	$36.18	Today
S120-APC	Customer Inspired! FC/APC Fiber Adapter Cap with Internal SM1 (1.035"-40) Threads, Wide Key (2.2 mm)	$36.18	Today
S120-SMA	SMA Fiber Adapter Cap with Internal SM1 (1.035"-40) Threads	$46.33	Today
S120-ST	ST/PC Fiber Adapter Cap with Internal SM1 (1.035"-40) Threads	$46.33	Today
S120-SC	SC/PC Fiber Adapter Cap with Internal SM1 (1.035"-40) Threads	$58.21	Today
S120-LC	LC/PC Fiber Adapter Cap with Internal SM1 (1.035"-40) Threads	$58.21	Today
S120-25	Customer Inspired! Ø2.5 mm Ferrule Adapter Cap with Internal SM1 (1.035"-40) Threads	$46.33	Today