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Fiber Optic Power Meters with Internal Sensor

  • Wavelength Range: 400 - 1700 nm
  • Power Range: -60 dBm to 23 dBm
  • Interchangeable Fiber Connector


Fiber Optic Power Meter

Easy-to-Read Large Digital Display

PM20 Power Meter with Fiber Adapter Removed

Additional SM05-Threaded Fiber Adapters Available Separately




Related Items

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Fiber Optic Power Meter Features

  • InGaAs (PM20C or PM20CH) or Si (PM20A) Sensors
  • Wavelength Range:
    • 400 nm - 1100 nm (Si)
    • 800 nm - 1700 nm (InGaAs)
  • Power Ranges:
    • -60 dBm to 16 dBm (1 nW - 40 mW) for PM20A
    • -60 dBm to 13 dBm (1 nW - 20 mW) for PM20C
    • -50 dBm to 23 dBm (10 nW - 200 mW) for PM20CH
  • Interchangeable Fiber Connector, FC Adapter Included (SC, ST, LC, or SMA Adapters Can be Ordered Separately)
  • Absolute and Relative Measurements Displayed in W, dBm, dB
  • NIST-Traceable Wavelength Calibration in 5 nm Steps
  • 50 Hours of Operation Between Charges

The PM20 Series of Fiber Optic Power Meters are robust, full-featured, handheld instruments, which together cover the full range of optical fiber applications within the 400 - 1700 nm range with optical powers ranging from -60 dBm to +23 dBm (1 nW - 200 mW). A rugged enclosure, internal sensors, and kickstand make these models ideal for field or lab applications.

Efficient, low-power circuitry provides long battery operation. The alphanumeric 8-digit LCD display allows easy power read-outs. The operation of the device is intuitive due to the clearly labeled key pad. All common features like wavelength setting, relative measurements, power read-out, and auto-shutdown are included. The PM20 is powered by a built-in rechargeable NiMH battery or by the included AC adapter that also recharges the battery. The unit comes with an FC fiber adapter that works with both FC/PC and FC/APC. Most industry standard fiber adapters (i.e. SMA, SC, ST, FC, and LC) are available for purchase and can be easily installed.

Thorlabs' Power Meter Compatibility Chart provides an overview of our complete optical and laser power meter product line, including sensor heads and compatibility information.

Each console comes with the following: the console with built-in sensor, FC fiber adapter (for FC/PC or FC/APC), 12 VDC power supply (PMPS12), Certificate of Calibration, and operating manual.

Power Meter Item #PM20APM20CPM20CH
Sensor Specifications
Optical Power Range -60 dBm to 16 dBm
(1 nW - 40 mW)
-60 dBm to 13 dBm
(1 nW - 20 mW)
-50 dBm to 23 dBm
(10 nW - 200 mW)
Spectral Range 400 - 1100 nm 800 - 1700 nm
Detector Type Silicon InGaAs
Sensor Size 3.6 x 3.6 mm Ø2 mm
Input Aperture 3.6 x 3.6 mm Ø2 mm
Aperture Thread SM05 Thread (0.535"-40) for Fiber Adapters
Fiber Adapter Included for FC Connectors (FC/PC or FC/APC)
Measurement Uncertainty ±0.25 dB
Measurement Standard NIST Traceable
Optical Damage Threshold 50 W/cm²
General Console Specifications
Detector Compatibility -
Display Type Alphanumeric 8-Digits LCD
Display Format 4 Digit Read Out with Units and Symbols
Power Units dBm, dB, nW, µW, mW
Resolution 14 bit
Sample Rate 10 Hz
Dimensions (H x W x D) w/ Holster 125 x 80 x 39 mm (4.9" x 3.1" x 1.5")
Weight 0.2 kg (0.44 lbs)
Operating Temperature 5 °C to 40 °C (Non-Condensing)
Storage Temperature -20 °C to 70 °C
Power Management
Battery Operation Internal NiMH Battery Pack, 150 mAh, 6 V
Operating Time 50+ Hours
Shutdown Manual, Auto 5 Minutes, or Auto 60 Minutes
Charger 3-Hour Battery Charger Included
Charger Power Supply Input: 85 - 265 VAC, 50 - 60 Hz; Output: 12 VDC @ 0.85 A

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

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Posted Comments:
Posted Date:2017-11-22 18:06:31.78
Can the charger be bought separately? If so, how much do they cost? Thanks, Sincerely, -David-
Posted Date:2017-11-27 08:42:52.0
This is a response from Moritz at Thorlabs. Thank you for your inquiry. Currently we do not offer a replacement power supply as standard product. However, any power supply with the following specifications can be used: 12V, 850mA, 2.1mm/5.5mm plug. I will contact you directly for further information.
Posted Date:2017-02-15 14:08:06.713
Hi! We have used a P20A unit for a long time and it seems like the battery has suffered quite a bit - after recharging it until 'battery is full' it takes only a couple of minutes until it says 'battery low' and with the AC plugged in there is a constant 'charging' text getting in the way of the actual measurement. Is there any way to replyce the battery or at least turn of the recharging message blinking?
Posted Date:2017-02-21 03:16:46.0
This is a response from Wolfgang at Thorlabs. Thank you very much for your inquiry. Yes, we can exchange the battery in these powermeters. I have contacted you directly to arrange the exchange.
Posted Date:2014-08-21 08:36:54.13
Just a follow-up to the previous response about the active area of the PM20A. The specs on the webpage say 3.6 mm^2, but the manual says (3.6 mm x 3.6 mm), which is correct? Since you mentioned the possibility of the beam being too large at the sensor, I'm curious what is the max acceptable NA for a single-mode fiber to avoid this issue (or if you could just tell me the approximate distance from the fiber tip to the sensor). Thanks!
Posted Date:2014-08-22 10:04:06.0
This is a response from Stefan at Thorlabs. Thank you very much for your inquiry.The sensor size is like stated in the manual on page 10 3.6mm x 3.6mm I am sorry if the information on the website were confusing here. The distance between ferule and detector plane is 3,7 +/- 0,3mm. I will contact you directly to discuss you application in detail.
Posted Date:2014-04-17 17:17:37.477
Dear Tech-support, could you please confirm if PM20A is compatible with standard 1mm POF (@650nm and 850nm)? best regards Michal
Posted Date:2014-04-25 04:12:55.0
This is a response from Stefan at Thorlabs. Thank you very much for your inquiry. To decide if a fiber is suitable we would need to know the NA and diameter, since it is possible to over illuminate the sensor. We specify the sensor size with 3.6 mm^2 active area. If the beam is larger, in the plane of the sensor, you will loose light and measure accuracy will be effected. Also, the damage threshold of the sensor may be an issue. We specify a damage threshold of 50 W/cm2. If your fiber has one of the standard connectors, you can exchange the FC/PC adapter for one of the adapters we provide as accessories on our website: Regarding the wavelength range, both 650nm and 850nm lie within the specified wavelength range of the built-in Si detector. To discuss in more detail the compatibility of your specific light source + fiber unit with our PM20A I will like to contact your directly.
Posted Date:2011-12-13 11:59:00.0
Response from Buki at Thorlabs: We have contacted you to get more information about your request.
Posted Date:2011-12-13 09:32:37.0
Gentlemen The power to put has function of guarded information
Posted Date:2011-03-22 10:43:00.0
Response from Javier at Thorlabs to anjonslay: Thank you very much for your interest in our products. A representative from our China sales office will contact you directly with pricing and availability information for our PM20C power meter. You can also reach this office via phone or e-mail: Phone: +86 (0)21-32513486 or +86 (0)21-32513482 Email:
Posted Date:2011-03-22 17:24:06.0
??! ?????????????????????????:PM20C - Fiber Power Meter,?????:PM20-FC - FC Fiber Adapter Cap with internal SM05 Thread?????,????????????,???????????????!?????????????????????????????????????????!?????!??! ??????! ??/????/??????
Posted Date:2009-12-28 09:27:01.0
PM20A passar utmärkt för att mäta effekten ur en laser diod med den effekt och vågläng som du vill mäta. PM20A är lättanvänd och effekten läses ut direkt på displayen Till PM20A finns dessutom olika fiber adaptrar under sectionen Accessories. The PM20A will work perfect for measuring the power of the laser diode you want to measure. The PM20A is easy to use and the power can be read directly on the display. Different fiber connectors are available under the section Accessories
Posted Date:2009-12-27 13:19:08.0
Hej - jag jobbar med laserbehandlingar mot tunnhårighet. Vi vill nu jämföra lasrar på marknaden. Alla lasrar på denna marknad säger sig ge 5mW av 650nm våglängd. Dioderna är fastsatta på plattor så jag måste ha en bärbar enhet för att komma åt att mäta eller om det finns någon fiberadapter att sätta mot dioden och att mätinstrumentet står på ett bord bredvid. Tror ni att ni har någon sådan produkt för oss? Det är inte superprecision jag är ute efter men absolut ingen leksak heller. Mats Stolt 0701 910 110 - 08 20 00 18
Posted Date:2008-01-04 11:56:03.0
The PM20C does indeed come with a FC-adaptor. That item is available under the "accessories" section in case you need to purchase another one. The ST adaptor is avilable using the orer code (PM20-ST). Shortly, you will also see an LC adapter featured on this page (PM20-LC). We hope this information is helpful and apologize for the confusion.
Posted Date:2008-01-04 05:52:49.0
dear madam/sir recently I have ordered a PM20C from you, plus some extra adaptors. there is some small discrepancy here: in the specs from the PM20C it says that it comes with an FC adaptor included, and that SC, ST and SMA can be ordered as extras. however in the list of extras you can only choose FC (again?) SC and SMA. can you please check with what standard adaptor the PM20C really comes and/or provide me with an ordering code for the ST-adaptor? By the way, when will you be delivering the ordred PM20C? regards, ruud groenewegen. royal nioz, netherlands.
Posted Date:2007-10-08 10:39:42.0
Thank you for suggestion for this page. We now list power ranges in decibels as well as milliwatts. We hope this added information is helpful.
Posted Date:2007-10-05 20:30:24.0
Since we don't all think in dB can you also provide power range in units of mW.

Fiber Optic Power Meters with Internal Sensor

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available / Ships
PM20A Support Documentation
PM20AFiber Optic Power Meter, 400 nm - 1100 nm, -60 dBm to +16 dBm (1 nW - 40 mW)
PM20C Support Documentation
PM20CFiber Power Meter, 800 nm - 1700 nm, -60 dBm to +13 dBm (1 nW - 20 mW)
PM20CH Support Documentation
PM20CHFiber Power Meter, 800 nm - 1700 nm, -50 to +23 dBm (10 nW - 200 mW)

Accessories for PM20 Power Meters

These adapters are compatible with devices that feature external SM05 threading such as our S150C Series Fiber Power Meter Sensors, PM160 wireless power meter, and the Fiber Optic Power Meters above.

Part Number PM20-FC PM20-SC PM20-LC PM20-SMA PM20-ST
Adapter Image
(Click the Image to Enlarge)
Connector Type FC/PC SC LC SMA ST
Thread Internal SM05 (0.535"-40)
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available / Ships
PM20-FC Support Documentation
PM20-FCFC/PC Fiber Adapter Cap with Internal SM05 (0.535"-40) Thread
3-5 Days
PM20-SC Support Documentation
PM20-SCSC/PC Fiber Adapter Cap with Internal SM05 (0.535"-40) Thread
PM20-LC Support Documentation
PM20-LCCustomer Inspired!LC/PC Fiber Adapter Cap with Internal SM05 (0.535"-40) Thread
Lead Time
PM20-SMA Support Documentation
PM20-SMASMA Fiber Adapter Cap with Internal SM05 (0.535"-40) Thread
PM20-ST Support Documentation
PM20-STST/PC Fiber Adapter Cap with Internal SM05 (0.535"-40) Thread
PMPS12 Support Documentation
PMPS12Power Supply 12VDC for PM20, PM30, PM50 Power Meter Series
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