OTP-A Fiber Optic Temperature Sensor

Multi-purpose fiber optic temperature sensor

Opsens Solutions’ OTP-A fiber optic temperature sensor offers the highest performances in the industry. The OTP-A sensor (Patent #7.259.862) uses the temperature-dependent birefringence of specially selected crystal as the temperature transduction mechanism. Because of the pure monocrystalline material used, the OTP-A does not shows thermal creeping or aging as with other fiber optic sensors based on the thermal dilatation of glass optical fibers.

Combined with Opsens’ WLPI signal conditioning technology (Patent #7,259,862) and with the inherent advantages of fiber optics, the OTP-A delivers unprecedented  repeatability and reliability in the most adverse conditions such as high level of EM, RF, MR and microwavefields environments as well as with high voltage and rapid temperature cycling conditions. The OTP-A is designed for relatively dry environment without significant condensing humidity. For such conditions, the fully sealed OTP-B is more suitable and can even be fully immersed in liquid permanently.

The standard operating range of the OTP-A is from -40 °C to +250 °C. The OTP-A is compatible with all Opsens’ WLPI signal conditioners. This compact and robust fiber optic temperature sensor, available in different cables and sheath options, is customizable according to customer specific applications or for OEM-type applications.


  • Small and robust design
  • Good accuracy
  • Outstanding repeatability
  • EMI/RFI and microwave immune
  • Intrinsically safe
  • OEM-type and custom version


  • EM, RF and microwave environments
  • High voltage environments
  • Nuclear and hazardous environments
  • Microwave assisted chemistry
  • Sterilization applications
  • In-situ process control
  • RF and microwave drying applications
Temperature operating and calibrated range

-40 °C to +250 °C


± 1.0 °C @ ± 3.3 sigma limit (99.9% confidence level)

Response time

1.5 s typical (Depends on packaging and measuring conditions)

Operating humidity range

0-100 %

EMI/RFI susceptibility

Complete immunity


NIST traceable

Cable length

1.5 meters standard (Other lengths available)

Optical connector

SC standard

Cable sheathing

Teflon™ PFA

Signal conditioner compatibility

All Opsens Solutions’ WLPI signal conditioners

Opsens Solutions Inc. reserves the right to make any changes to the above specifications without prior notice.

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