AQ6377 Five Micron Optical Spectrum Analyzer 1900 - 5500 nm

The AQ6377 is the latest version of our optical spectrum analyzer series, offering extended wavelength coverage into the MWIR region from 1900 - 5500 nm. Its long wavelength range makes the AQ6377 ideal for environmental sensing and medical applications. 

Key features of the AQ6377 optical spectrum analyzer include gas purging input ports/output ports, a built-in cut filter for high order diffracted light​​​​​​, and a novel double speed mode which increases the sweep speed up to 2 times compared to the standard sweep mode.


Wavelength range: 1900 to 5500 nm 
Wavelength resolution settings: 0.2 to 5 nm 
Wavelength accuracy: ±0.5 nm 
Level range: −60 to +13 dBm 
Dynamic range: 50 dB 

Key Features

  • Wavelength range: 1900 to 5500 nm 
  • 5 wavelength resolution settings: 0.2 to 5 nm
    Enables the user to choose the best value according to the device/system under test.
  • Wide measurable level range: −60 to +13 dBm
    Suitable to measure high power as well as low power sources used in different fields of application. Sensitivity: HIGH1-3 are only high dynamic mode.
  • Wavelength accuracy: ±0.5 nm
    Easily maintained due to the built-in Calibration Function and wavelength reference source.
  • Close-in dynamic range: 50 dB

AQ6377 dynamic range

Measurement example of 4.3 μm DFB laser
(Res: 0.2 nm, Span: 50 nm)

  • Horizontal scale also in Wave Number (cm−1)
    In addition to the commonly-used scales in wavelength (nm) and frequency (THz).

Purge Feature

Due to the high resolution and sensitivity of the AQ6377, it can actually detect the presence of water molecules in the air. The water vapor is detected in the upper Near-IR wavelength region and could overlap with or mask the spectral characteristics of the actual device under test in that particular region.

By continuously supplying a pure purge gas such as nitrogen to the monochromator through the ports on the back panel, the AQ6377 can reduce the influence of water vapor absorptions and provide more reliable and accurate measurements than ever before.

Built-in Cut Filter for High Order Diffracted Light

Due to the diffractive technology used, the monochromator in some circumstances could generate high order diffracted light, which appears at wavelengths equal to the integral multiple of input wavelengths.

By cutting incoming light below 1500 nm with the built-in filter, the AQ6377 drastically reduces the influence of high order diffracted light on the measurement. Thus, the measured data are always reliable and replicate the real signal under test.

Double Speed Mode

Increases the sweep speed up to 2 times compared to the standard sweep mode, with only a 2 dB penalty to the standard sensitivity value.

Free-Space Optical Input

optical input structureThe AQ6377 uses a free-space optical input structure (i.e. no fiber is mounted inside the instrument), most effective for guaranteeing high coupling efficiency, measurement repeatability, and no maintenance.

This smart solution is:

  • WORRY-FREE: no internal fiber can be scratched or get dirty by inaccurate coupling of fibers
  • MAINTENANCE-FREE: no internal fiber has to be cleaned
  • VERSATILE: the instrument accepts both /PC and /APC connectors
  • DUAL PURPOSE: the instrument accepts both Single-Mode and Multi-Mode fibers without being affected by the high insertion loss from MM-SM fibers matching

Key Functions

Data Logging Function

Records analysis results such as distributed feedback laser diode (DFB-LD) analysis data and multi-peak measurements at up to 10,000 points per channel with time stamps.

Data Logging Function

Advanced Marker Function 

Adds markers to obtain the power spectral density and the integrated power of a designated spectrum. This new feature makes it easy to get an OSNR value of the signal, whether modulated or not, directly from its spectrum. 

Building Automated Test Systems 

Thanks to the built-in Macro Programming Function, all AQ6370 Series models can perform automatic measurements and control external equipment through their remote interfaces. 

GP-IB, RS-232 and Ethernet ports enable the instrument to be remotely controlled by a PC using standard SCPI-compatible or proprietary AQ6317-compatible commands. LabVIEW® drivers are also available. 

Built-in Calibration Source 

Ambient temperature change, vibrations, and shock affect the measurement accuracy of high precision products such as optical spectrum analyzers. Yokogawa OSAs must be able to deliver the precise measurements for which they were designed; therefore, our instruments are equipped with a light source for calibration. 

The calibration process is fully automatic and takes only 2 minutes to complete. It includes: 

  • The Optical Alignment function, which automatically aligns the optical path in the monochromator to assure the level accuracy
  • The Wavelength Calibration function, which automatically calibrates the spectrum analyzer with the reference source to ensure the wavelength accuracy

Built-in analysis functions to increase your testing efficiency

Spectrum Width Analysis

You can display the spectrum width and center wavelength using the following 4 types of calculation:

  • THRESH method
  • ENVELOPE method
  • RMS method
  • PEAK RMS method

Notch Width Measurement

With this function it is possible to measure pass bandwidth / notch width from the measured waveform of a filter with V-type or U-type wavelength characteristics.

Light Source Analysis

Light source parameters can be analyzed from the measured waveform of each type of light source among DFB-LD, FP-LD and LED.PMD Measurement

It is possible to measure the Polarization Mode Dispersion (PMD) of a DUT (such as an optical fiber) by using the instrument in combination with an Analyzer, Polarization Controller, Polarizer, and an Amplified Spontaneous Emission (ASE) light source, High-output LED light source, or other wideband light source.

WDM (OSNR) Analysis

With this function it is easy to analyze WDM transmission signals. You can also measure OSNR of a DWDM transmission system with 50 GHz spacing. Measurements of WDM signal wavelength, level, wavelength interval, and OSNR can be made collectively on up to 1024 channels, and the analysis results can be displayed in a data table.

Optical Amp Analysis

Gain and Noise figure measurements can be made on signal light waveforms going into optical amplifiers, as well as light leaving the optical amplifiers.

Optical Filter Characteristics Measurement

Optical filter characteristics can be measured from the measured waveforms of the light, from source, going into optical filters, as well as from the measured waveforms of light being output from optical filters. Analysis can be performed not only on optical filters with one mode, but also multimode filters (e.g WDM Filters).

Measurement of Level Fluctuations in Single-Wavelength Light

This function is used to measure changes over time in the level of a specific wavelength level. The sweep width is set to 0 nm, and measurement of the single-wavelength light is taken. The horizontal axis is the time axes. It is useful for purposes such as optical axis alignment when a light source is input to an optical fiber.

Template Analysis

The template function compares preset reference data (template data) with a measured waveform. In addition, if a function for displaying the target spectrum (target line) on the measurement screen is used, the target spectrum can be referenced while adjusting the optical axis of an optical device.

Go/No Go Judgment

The Go/No Go test function compares the active trace waveform against reference data (template data) preset by the user, and performs a test on the measured waveform (Go/No Go test).
This function can be used effectively in situations such as pass/fail tests on production lines.

Analysis between Line Markers / in the Zoom Area

The instruments perform the analysis of the signal contained into boundaries selected by means of line markers or zoomed area.

AQ9447 Connector Adapter

  • AQ9447 Connector Adapters
  • For optical input port
  • AQ6370 Series Optical Spectrum Analyzer Accessories

AQ9441 Connector Adapter

Suffix Descriptions
-FC FC type
-SC SC type

751535-E5 Rack mounting kit

RACK MOUNTING KIT For an EIA-compliant Single-housing Rack

NA Conversion Adapter

  • 735383-A001, A002 numerical aperture conversion adapters
  • Half numerical aperture of optical fiber 
  • AQ6370 series optical spectrum analyzers' free-space optical input structure 
Application Note

OSA Macro Program Function

The OSA Macro Program Function enables automated measurement by creating programs for entry of measurement conditions and other tasks. Users can program a sequence of measurement procedures from entry of measurement conditions (e.g., wavelength sweep width, setting resolution) to analyses, data saving, output, and others and eliminates redundant procedures on the production line. The function acts as a controller of other connected devices through the LAN or RS232C port and allows users to build an automatic measuring system without using an external PC and input measurement conditions or output measured results while programs are running.


To accurately measure pulsed light using an optical spectrum analyzer (OSA), it is necessary to understand the characteristics of the OSA and select the appropriate measurement method and settings.

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