AQ6370D Telecom Optical Spectrum Analyzer 600 - 1700 nm (DISCONTINUED)

Notice: This product was discontinued on Dec 1, 2023. See this replacement product:

The AQ6370D is the latest iteration of the most popular Telecom class OSA from Yokogawa. It offers a versatile wavelength range of 600 nm to 1700 nm ideally suited for both Telecommunications and general-purpose applications. The unique free space input design allows testing of both DWDM class Singlemode and VCSEL sourced multi-mode fibers in one single model.
Newly added functions include data logging, gate sampling, resolution calibration, an advanced marker function, and an enhanced auto-sweep mode.

Measuring power supply noise with spectrum analyzer:
Calibrate resolution for bandwidth accuracy for the best noise measurement results and optical power measurement results for wideband light sources. 
Smoothing attenuates excessive noise in a measured waveform.
The following types of data are recorded for WDM analysis and peaks.

  • WDM analysis: Wavelength, level, SNR (signal-to-noise ratio)
  • Peak: Wavelength, level
Advancing Market Capabilities
The extreme test requirements of our research called for an OSA with extended MIR spectrum bandwidth capabilities up to 5μm, but we couldn’t find one on the market capable of measuring optical inputs at these wavelengths. Yokogawa Test&Measurement rose to the challenge and developed a new OSA model for us that would. Not only do we now have an instrument that is practically custom-made for our needs, it provides repeatable, accurate, and trusted measurement outputs and is easy to learn and use. Their equipment and ability to create a new optical measurement solution has definitely increased the overall efficiency and productivity of our research team.
— Martin Bernier, PhD, P.Eng.
Full Professor, Centre de Optique, Photonique, et Laser, Université Laval

Are you involved with Optical Testing for learning?
Click here to learn about our special OSAs for Education.

Free Yokogawa Fiber-Optic Communication Poster

World-Class Optical Performance

  • Wavelength range: 600 to 1700nm
  • High wavelength accuracy: ±0.01nm
  • High wavelength resolution: 0.02nm
  • Wide dynamic range: 78dB typ.
  • Wide level range: +20 to -90dBm
  • Fast measurement: 0.2 sec. (100nm span)
  • Applicable to single-mode and multimode fibers

Standard and High-Performance Models

There are two models available, Standard and High performance. The High performance model provides even higher wavelength accuracy and dynamic range.

High wavelength resolution: 0.02nm

High Wavelength Accuracy: ±0.01nm

  • High performance model: ±0.01nm (C band)
  • Standard model: ±0.02nm (C+L band)
Wavelength Range Standard (-12) High Performance (-22)
1520 to 1580 nm
1580 to 1620 nm
1450 to 1520 nm
Full range
±0.02 nm
±0.02 nm
±0.04 nm
±0.1 nm
±0.01 nm
±0.02 nm

±0.04 nm
±0.1 nm

Ultra-High Dynamic Range: 78dB typ.

With the reduced stray-light in the monochromator, AQ6370D achieves ultra-high dynamic range of typ. 78dB.

  Standard (-12) High Performance (-22)
Peak± 1.0 nm
Peak± 0.4 nm
Peak± 0.2 nm
73 dB
62 dB
45 dB
73 dB (Typ.78dB)
64 dB (Typ.70dB)
50 dB (Typ.55dB)
*Resolution setting 0.05 nm

AQ6370D 1 1

Example of the dynamic range
Peak ±1.0nm, Resolution setting 0.05 nm,
High dynamic mode: ON, High performance model

Sharper Filter Edge

The high performance model can also achieve a higher dynamic range within 0.2nm of the peak wavelength. With the sharper spectral characteristics of the monochromator, spectral signals in close proximity can be separated clearly and measured accurately.


  Standard (-12) High Performance (-22)
Peak± 0.2 nm
Peak± 0.1 nm
55 dB
37 dB
58 dB (Typ.60dB)
45 dB (Typ.50dB)
*Resolution setting 0.02 nm

AQ6370D 2

Example of the spectral shape

Stray-light suppression ratio: 80dB typ.

This new specification provides stray-light suppression capability when High dynamic mode, usually taking longer measurement time, is not used. The AQ6370D contributes to shortening the measurement time with the high stray light suppression ratio.
Standard (AQ6370D-12) High Performance (AQ6370D-22)
73dB 76dB (Typ. 80dB)
*Resolution setting 0.1nm

AQ6370D 3

Example of the stray-light suppression ratio
High dynamic mode: ON, Resolution setting 0.1 nm, High performance model

Wide Level Range: +20DBm to -90dBm

The AQ6370D can measure high power sources such as optical amplifiers and pump lasers for Raman amplifiers, and very weak optical signals as well. Measurement sensitivity can be chosen from seven categories according to test applications and measurement speed requirements.

  • Improved level sensitivity: -85dBm (1000 to 1300nm)
  • Smoothing Function - Reduce noise on the measured spectrum
  • High dynamic mode - Obtain a better dynamic range by reducing the influence of stray-light, which is caused when the input is a strong optical signal.

Free Space Input

  • AQ6370D 4Multimode and single mode fiber on the same OSA.
  • AQ6370D's low insertion loss for multimode fiber is also beneficial to maintain the excellent measurement efficiency.
  • Small insertion loss variation at the input
  • connector increases measurement repeatability.
  • No damage connecting fibers
  • because there is no physical contact.
  • APC level correction
  • The APC level correction function corrects the level offset caused by an insertion loss of angled PC connector.

Excellent Efficiency

Fast Sweep: 0.2sec./100nm

With an advanced monochromator, faster electrical circuits, and noise reduction techniques, the AQ6370D achieves fast measurement speed even when measuring a steep spectrum from DFB-LD or DWDM signals, or when measuring a low power signal from a broadband light source.

Fast Remote Interface (Ethernet, GP-IB)

Wide Span Sweep yet High Resolution

The 50,001 data sampling points expands measurement range in a single sweep while keeping a high wavelength resolution. This makes your measurement easier and more efficient than conventional systems.

Easy Operation

Trace Zooming

  • Change display conditions, such as center wavelength and span, by clicking and dragging the mouse.
  • Enlarge your area of interest instantly and move it at will.

Mouse & Keyboard Operation

  • Front panel operation proven intuitive and easy to use by our many of users.
  • Even easier with a mouse.
  • The keyboard helps enter labels and file names.

Easy Data Handling

  • AQ6370D 5USB Storage
  • USB interfaces support large-capacity removable memory and hard disk drives.
  • 512MB Internal Memory
  • for over 20,000 traces
  • All-at-Once Trace Filing
  • All seven traces can be saved in one file at once.

Data Logging Function

The Data Logging function records analysis results such as WDM analysis (OSNR, optical signal/noise ratio), distributed feedback laser diode (DFB-LD) analysis, and multi-peak measurements at up to 10,000 points per channel with time stamps. Recorded data can be displayed in table and graphical forms. This function is useful for the long-term stability testing and temperature cycle testing of systems and devices. The optical spectrum of each measurement can also be stored for reviewing and troubleshooting.

AQ6370D 8

Example of the data logging display

Advanced marker function

The Advanced Marker function adds markers to obtain the power 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.

AQ6370D 8

Example of the advanced marker

Gate sampling function

The Gate Sampling function facilitates the recirculating loop testing of optical transmission systems. Using an external gate signal, the AQ6370D obtains the optical spectrum of the signal which is passing through a certain loop. The advantage of this approach is its speed compared with the conventional External Trigger or Sweep Enable function.

Resolution calibration function

The Resolution Calibration function is used to calibrate the noise equivalent bandwidth with an external light source. With this new feature, the measurements of power density of a broad spectrum light source will be more accurate

Various Analysis Functions

7 Indvidual Traces

  • Simultaneous multi-trace display
  • Calculation between traces (subtraction between traces)
  • Max/Min hold

15 Specific Data Analysis Functions
for popular applications, such as:

  • Spectral width analysis
  • WDM (OSNR) analysis
  • WDM-NF (EDFA) analysis
  • DFB-LD analysis
  • FP-LD analysis
  • LED analysis
  • SMSR analysis
  • Various filter analysis
  • With the macro programming, multiple analyses can be combined and executed automatically.

Building Automated Test System

Macro Programming

AQ6370D 6

  • Build a simple auto-measurement system without an external controller.
  • Easy to create test program by recording the user's actual key strokes and parameter selections.

Fast Remote Interfaces

  • GP-IB, RS-232, and Ethernet (10/100Base-T) interfaces
  • Improve the testing throughput of test systems by the fast measurement, command processing, and data transfer speed.
  • SCPI compatible commands and AQ6317 Emulation Mode
  • LabVIEW® Driver available

Easy to Keep Accurate

Ambient condition change, vibration and shock to an optical precision product, like an optical spectrum analyzer, will effect the optical components, and eventually degrade optical performance. Using standard functions, AQ6370D can maintain its high optical performance within a couple of minutes so that you can quickly start a measurement.

Built-in wavelength reference source

  • AQ6370D comes equipped with a wavelength reference source for the wavelength calibration and optical alignment.

Wavelength calibration function

  • Automatically calibrates with the built-in wavelength reference or an external light source, to ensure the wavelength accuracy.

Optical alignment function

  • Automatically aligns the optical path in the monochromator using the built-in source to maintain high performance.

AQ6370D's overall high performance can cover not only manufacturing of optical devices and optical transmission systems but also research and development, and a variety of other applications.

  • Optical active devices
  • Laser diode/Fiber laser/Optical amplifier/Optical transceiver
  • Optical passive devices
  • Filter/FBG/AWG/WSS/ROADM/Optical fiber
  • Optical transmission equipment (DWDM, CWDM)
  • Development support of Applied photonics equipment
  • LiDAR and 3D Sensing optical sources

LiDAR, Laser Diode free space beam Measurement

The free space beam from device level optical sources for LiDAR, 3D sensing, Wafer Chips, optical transceiver TOSAs and laser diodes (LD) in general may be conveniently coupled to a fiber input using various beam capture solutions to optimize the spectral detection performance of the OSA.

For performing long term testing of extreme temperature effects for automotive LiDAR devices as an example, learn how the Data Logging Function can be utilized to eliminate time consuming program development and validation.

OSNR Measurement on DWDM System

AQ6370D 7

AQ6370D's wide close-in dynamic range allows accurate OSNR measurement of DWDM transmission systems (up to 50 GHz spacing). The built-in WDM analysis function analyzes the measured waveform and shows peak wavelength, peak level and OSNR of WDM signals up to 1024 channels simultaneously.

Optical Amplifier (EDFA) Measurement

AQ6370D 8

The ASE interpolation method is used to measure gain, NF, and key parameters for optical fiber amplifier evaluation. With WDM-NF analysis function, up to 1024 channels of multiplexed signals can simultaneously be tested. An ASE level for NF measurements is calculated by using a curve-fit function for each WDM channel.

LCA Reduced energy, emission of CO2, NOx and SOx about 17% compared to the previous model.

PDFResults of Life Cycle Assessment

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

Numerical Aperture Conversion Fiber

By connecting a GI 50 or GI 62.5 optical fiber with a relatively large NA to the NA Conversion Fiber, the NA Conversion Fiber reduces the loss that occurs at the input and improves the measurement dynamic range during passive device measurements and the stability of optical level measurements during active device measurements.

751535-E5 Rack mounting kit

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


Lack of reliable high-speed internet access in rural regions, due to complicated logistics and the considerable costs involved to extend land-based networks to these areas, has inspired a wave of next-generation applications that will provide greater accessibility and reliability. Making use of “space laser” networks, these revolutionary solutions can relay digital traffic via low Earth orbit (LEO) satellite systems to provide low-latency, high-speed broadband services to communities typically beyond the reach of standard wireless and fiber networks.


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.


A new type of computer based on the theory of quantum mechanics, a quantum computer, is currently in development by researchers around the globe. The theory of quantum mechanics describes nature at the atomic and subatomic level. Quantum technology has the potential to build powerful tools that process information using the properties of atoms, photons, and electrons. These quantum computers could also address challenges of much greater complexity than what today's computers can solve, and help further advancements in science, technology, medicine, and more.

With countries spending billions of dollars, the race for who can produce the first practical, commercialized quantum computer is on. There are currently several approaches to build this sort of computer, and this all begins with creating and initializing quantum bits, also known as qubits.


The extreme test requirements of our research called for an OSA with extended MIR spectrum bandwidth capabilities up to 5μm, but we couldn’t find one on the market capable of measuring optical inputs at these wavelengths. Yokogawa Test&Measurement rose to the challenge and developed a new OSA model for us that would. Not only do we now have an instrument that is practically custom-made for our needs, it provides repeatable, accurate, and trusted measurement outputs and is easy to learn and use. Their equipment and ability to create a new optical measurement solution has definitely increased the overall efficiency and productivity of our research team.

— Martin Bernier, PhD, P.Eng., Full Professor, Centre de Optique, Photonique, et Laser, Université Laval


In a research paper published on, a team of researchers from the University of Virginia, Peking University, Shanxi University, and California Institute of Technology use a Yokogawa Test&Measurement Optical Spectrum Analyzer in order to achieve spectrum measurements above 1200 nm.


In research published on IEEE Xplore, researchers from Harbin Engineering University, the University of Limerick, and the Technological University Dublin use a Yokogawa Test&Measurement AQ6370C Optical Spectrum Analyzer to measure wavelengths when fiber is subjected to temperature changes.


University of Central Florida researcher uses a Yokogawa Test&Measurement AQ6370B Optical Spectrum Analyzer to map the properties of a new silicon waveguide fiber.

Product Overviews


    Introducing the new Yokogawa Test&Measurement AQ6380 Optical Spectrum Analyzer. This new OSA includes many sought-after features including:

    • An unprecedented 5 pm wavelength resolution
    • ±5 pm wavelength accuracy
    • 1200 nm to 1650 nm wavelength range
    • 65 dB wide close-in dynamic range
    • 80 dB stray light suppression
    • Automated wavelength calibration
    • Gas purging
    • DUT-oriented interface and test apps
    • Backward-compatible remote interface
    • 10.4in intuitive touchscreen
    • Up to 20x faster measurement
    • Remote operation capabilities



    We are going live on YouTube to answer your questions about the Yokogawa Test&Measurement AQ6370 Series of optical spectrum analyzers. Join us to discuss how to make the most of these versatile instruments based on your optical application needs. A few examples are fiber testing, laser/LED testing, LiDAR, optical passive components (filters), and optical transmission equipment (DWDM, CWDM). Whether you’ve worked with an OSA for years or curious if it is a good fit for your work or research, this live stream can help.

    Potential items for review include but are not limited to:

    • Span
    • Sweep
    • Calibration
    • Analysis
    • Cursors/Markers
    • PC-Based Remote Viewing Software



    Mastering the fundamentals of optical wavelength measurements and having a solid understanding of measurement principles for optical sources and devices is key to measuring with confidence. This webinar provides a thorough review of these foundational elements and concepts as well as:

    • Fiber identification and recommendations for routine care
    • Measurement techniques for different optical measurement devices
    • Example wavelength-specific applications for visible light to over 3000 nm such as telecommunications, biomedical, and atmospheric gas sensing
    • Important considerations for selecting an optical spectrum analyzer

    There are countless technologies available for optical communications devices and systems validation. With so many specifics to take into consideration, it's not always easy for an engineer to determine the best networking and fiber optic measurement solution to address their measurement needs.

    Key discussions in this on-demand webinar include:

    • The what, why, and how of available options like optical spectrum analyzers, optical wavelength meters, optical power meters, variable attenuators, fixed and tunable laser sources, and more
    • How to improve the quality and value of results for both active and passive optical devices
    • Ways to streamline productivity and reduce costs while also achieving higher data transmission rates, longer-distance transmissions, immunity to EMI, lower signal loss, lower latency, enhanced security, and improved energy efficiency
    • Trends driven by applications such as AI, quantum, and inter-satellite laser communications (i.e., space lasers!)

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