Used Wavelength Meters for Sale

An optical wavelength meter (also called a wavemeter) measures the wavelength of a laser source with sub-picometer accuracy. Most instruments use a Fizeau interferometer — the laser signal passes through two partially reflective wedged plates, creating an interference pattern that a CCD detector reads. The fringe spacing encodes the wavelength. High-end Bristol and Burleigh units use Michelson or Fabry-Perot designs for accuracy below 0.1 pm. The instrument must warm up 15 to 30 minutes to reach thermal equilibrium before making accurate measurements.

A wavelength meter gives you the wavelength of one or a few lasers with very high accuracy — typically 0.1 to 1 pm — but gives no information about spectral shape, side-mode suppression, or broadband signals. An optical spectrum analyzer (OSA) shows you the full optical spectrum but with much coarser wavelength resolution (0.06 nm minimum on the best bench OSAs). Use a wavelength meter when you need to know exactly where a DFB laser is tuned. Use an OSA when you need to see the spectrum shape, SMSR, or multi-channel DWDM power distribution.

For verifying that a DFB laser hits its ITU-T grid channel, you need at least 5 pm absolute accuracy — the 100 GHz DWDM channel spacing is 800 pm, so even 10 pm uncertainty is adequate for channel assignment. For tunable laser characterization where you are measuring absolute wavelength accuracy across a wide tuning range, aim for 1 pm or better. For locking a laser to a narrow reference or characterizing linewidth indirectly, you need a Bristol-class instrument at 0.1 pm or better. The Agilent 86120/86122 series delivers 1 pm accuracy — adequate for most telecom work.

Multi-wavelength meters — the Agilent 86120B/C/D, the EXFO IQ-5320, the Advantest Q8331, and the Burleigh WA-7000 series — can resolve 2 to 128 simultaneous wavelengths by scanning the interference pattern and running a multi-peak algorithm. Single-wavelength instruments like the Burleigh WA-1600 or Burleigh WA-20 can only measure one laser at a time. If you are measuring DWDM channel wavelengths from a multi-channel source, you need a multi-wavelength meter. The Agilent 86122C measures up to 500 simultaneously, which covers full C-band DWDM channel sets.

Most bench wavelength meters accept FC/PC or FC/APC connectors as the primary input, with SC and LC adapters available as accessories. The Agilent 86120/86122 series uses a standard FC/PC input. Burleigh WA-series instruments use a direct fiber coupling with an FC connector. EXFO WA-1000 accepts FC/PC. Ensure the connector is clean before measurement — a dirty connector introduces back-reflection that creates interference artifacts and shifts the measured wavelength by 1 to 5 pm. Use a fiber scope before mating.

Annual NIST-traceable calibration is standard for instruments used in production or quality-system environments. In practice, the Fizeau interferometer design is very stable — a well-stored Agilent 86120C should hold calibration for two or three years if it has not been mechanically shocked. Instruments that have been shipped without proper foam packaging, stored at temperature extremes, or used heavily in a production environment need calibration before critical measurements. We calibrate against NIST-traceable reference wavelength standards at 1310 nm and 1550 nm.

On Burleigh WA-series instruments, the most common failure is the fiber input coupler — the ferrule housing wears and the alignment drifts, causing the coupled power to drop and the measurement uncertainty to increase. Older Burleigh units use fluorescent lamp sources for the reference; these degrade over years and need replacement. On Agilent 86120/86122 instruments, the internal reference laser can age and reduce signal-to-noise on the interferometer, producing unstable readings. Display and keypad issues are common on 10 to 15 year old units from shelf storage.

Wavelength meter calibration at Aumictech runs $450 for a standard pass/fail NIST-traceable certificate, or $650 for a certificate with full measured data at 1310 nm, 1490 nm, 1550 nm, and 1625 nm reference wavelengths. We include the warm-up period in our calibration procedure — the meter is powered on for 30 minutes before any measurements are taken. Turnaround is 1 to 3 business days after receipt. Free evaluation if the meter has a fault before calibration proceeds.