Bare Fiber Oxygen Microsensor


  • 50-70µm sharp sensor tip
  • Ultra-high speed response time (t90 < 0.3s)
  • With underwater SUB-connector (SUB)
  • No oxygen consumption
  • Negligible drift, >3 years shelf time

The fiber-optic oxygen sensors from PyroScience feature no oxygen consumption, no stirring sensitivity, an extremely long shelf time, resistance to corrosive environments (e.g. seawater) and are suitable for multiple applications in gas, water and aqueous samples.

This fiber-optic microsensor consist of an optical fiber (230 µm) with a sensor tip diameter of approximately 50-70 µm. Microsensors are perfectly suited for measurements in small samples and for profile measurements (e.g. in sediments, soils, plant tissue, biofilm) with high spatial resolution (microprofiling).

Typical applications:

Standard range. This sensor is specified for an optimum measuring range of 0 to 500 hPa oxygen (0 -250% air saturation). However, without specifications, it is possible to measure in up to 1 bar pure oxygen/100% oxygen saturation/100% O2. For detailed specifications, see the respective pdf file in the Downloads tab.

Bare fiber. The bare fiber oxygen sensors are principally identical to our Retractable Needle-Type oxygen sensors, but they come without any sensor housing.

Ultra-high speed (-UHS). Typical response times for 90% signal change (T90) in water and gas: <0.3 s. Measured for the transition from air into a stirred solution of 1% Na2SO3.

SUB-connector (-SUB). Underwater sensor connector (instead of standard ST-connector) needed for applications with underwater devices.

Easy calibration. A simple ambient air calibration can be performed with a few clicks (<1 minute for equilibrated setup). For precise oxygen measurements close to 0% we also offer easy-to-use calibration capsules (OXCAL). Simply dissolve the content of one calibration capsule in 100 ml distilled water, wait 10-15 minutes, perform the 0% calibration and start measurements with a calibrated sensor. For detailed calibration recommendations refer to the manual in the downloads tab.

Star sensor. This sensor is one of the world's best or only solutions in a certain application area, featuring for example a very fast response time, solvent resistance or a unique sensor format.

Applications. To get an overview of potential applications and to see our sensors in action, please visit our Applications site!

Sensor Versions. There are further versions available of this sensor type.  Please use the filter function or the inquiry form to find the suited sensor version for your application.

Price List

0% O2 Calibration Capsules 


For recommended 0% O2 calibration of optical oxygen sensors. Each capsule results in 50mL calibration solution (PU=10).

Every PyroScience oxygen meter with a SUB-connector is compatible to this sensor. Use this link to get a list of all compatible meters. Select additional requirements to find the optimal meter for you and your application!


Exemplary Setup


Choose the one channel underwater AquapHOX logger (AquapHOx-LX) with the bare fiber oxygen microsensor OXB50-UHS-SUB.