The OP508 was specifically designed as a cost effective solution for measuring, monitoring and logging insertion loss or power fluctuations. It is a small (4”x2”x1.25”) portable module designed to minimize movement and bending of the reference and test cables. This results in stable, accurate and repeatable measurements.


The OP508 is offered with a choice of 1mm or 3mm InGaAs, 2mm High Power InGaAs, or 3mm Silicon detectors; and most common connector options (FC, ST, SC, LC, etc…). It comes with a fixed optical interface allowing for a wide variety of applications. The USB-powered module connects directly to the computer. OptoTest provides drivers and applications that allow the user to perform common measurement tasks such as EXCEL data logging or time-stamped stability measurements.


  • Broad wavelength spectrum InGaAs: 830nm to 1700nm Silicon: 400nm to 1100nm
  • Measurement range InGaAs: +6dBm to -72dBm Silicon: +3dBm to -65dBm
  • Relative accuracy of 0.02dB*
  • Measurement display resolution down to 0.001dB
  • Fast data acquisition rate without compromising measurement accuracy
  • Variable sampling rate via software
  • Integrated temperature monitoring eliminates the need for an additional temperature sensor during long term stability tests


* Loss less than 10dB