How does a manual image measurement instrument perform scanning wavelength optical measurements? By combining one or more optical power meters with a tunable laser source (TLS), it supports the measurement of the relationship between optical power and wavelength. Such measurements are commonly used to determine the ratio of the input power to the output power of the device being measured, known as insertion loss, measured in dB. When the TLS tunes the wavelength within the selected range, the power meter will periodically sample the power at a set number of measurement points.

By synchronizing with TLS scanning through a trigger signal, these samples can achieve accurate correlation with corresponding wavelengths. Multiple power meters can simultaneously measure the output of multi-port devices (such as multiplexers, power splitters, and wavelength selectors). A measurement system can be assembled using TLS models 81600B, 81940A, or 81980A, along with power meters (such as 816x series modules or multi-port N7744A and N7745A) and the free N7700A IL software.

The programming process for these "wavelength scanning" routines is extremely simple, utilizing the free 816x plug-and-play drivers and enhancing the measurement capabilities with the N4150A optical foundation program library (PFL). This measurement device is connected to the 81610A return loss module post-TLS and can also measure optical reflections (return loss).

These laser sources are equipped with built-in wavelength monitoring capabilities, ensuring high wavelength accuracy and repeatability, especially during rapid wavelength scanning. These "wavelength record" data are synchronized with power meters via measurement trigger signals. For higher wavelength precision, bias calibration with gas reference signals is available, and PFL supports engineers in conveniently completing the calibration process.

InGaAs power detectors exhibit minimal response variation and high sensitivity within the single-mode fiber wavelength range of 1260-1630nm, making them an excellent tool for such measurements. The N7744A and N7745A power meters are particularly suited for these scanning wavelength measurements: their fast sampling rates and wide signal bandwidth ensure high-resolution results during rapid scanning without any distortion. Faster data transmission speeds enhance throughput, especially beneficial for scenarios with a high number of ports.