What are the wavelength limits of the 86140 optical spectrum analyzer family?

This depends on the mode you are operating. In the normal measurement mode, the wavelength measurement ranges from 600 to 1700 nm However, it is possible to turn these limits off.

When the wavelength limits are off, the wavelength range of the instrument increases from 400 to 2000 nm to turn off the wavelength limits, select the following keystrokes: "System", "More System Functions...", "Service Menu...", "Adv Service Functions...", "Wavelength Limit" and make sure it is turned off. You are now able to use the entire range from 400 to 2000 nm.

Be aware that by turning the wavelength limits off, you might now be making uncalibrated measurements. The measurements for wavelengths between 600 and 1700 nm will still be calibrated, even when the wavelength limits are turned off. However, the measurements for wavelengths outside of that area will be uncalibrated.