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High-Speed Spectrum Analyzer MS9740B for Optical Device Evaluation

High-Speed Spectrum Analyzer MS9740B for Optical Device Evaluation

Fast, high-performance optical-spectrum measurements supporting multiple modules to help cut optical device inspection times

The spread of next-generation 5G mobile communications and cloud services is increasing data traffic and network speeds, and capacities are expected to be increased using faster 10G, 100G, and 400G bit rates. Infrastructure operators are strengthening optical fiber circuits as well as increasing the speed of TRx equipment in data centers. These trends are expected to lead to rapidly increasing demand for optical devices used by high-speed communications equipment. To meet this demand, optical device makers require accurate instruments for measuring many different types of optical devices at high volumes on production lines.
With its excellent performance, high speed, and support for many different types of optical device, Anritsu’s Optical Spectrum Analyzer MS9740B is the ideal measurement solution for customers requiring secure, stable, and efficient optical spectrum tests of optical devices.

High Speed

Evaluation of optical spectra on optical-module production lines requires shorter measurement time per module (total inspection time from waveform sweeping by optical spectrum analyzer until data transfer to external controller) to increase production efficiency.

Anritsu MS9740B, Short Measurement Processing Time

Short Measurement Processing Time: Excellent Dynamic Range Cuts Measurement Processing Time by up to Half

Adding a new Fast mode to the MS9740B VBW (measurement sensitivity) setting while maintaining a dynamic range of better than 45 dB needed for evaluating active optical devices cuts the measurement processing time by up to half compared to previous instruments. Speeding-up measurement processing slashes device inspection times to improve production-line measurement efficiency and productivity.

Anritsu MS9740B, Up to Twice as Measurement Times

Anritsu MS9740B, Dynamic Range

GPIB Interface
SMSR Measurement Time (DFB Light Source)
VBW: 1 kHz_Fast (MS9740B)
1 kHz (MS9740A)
Resolution: 0.1 nm
Sweep Width: 30 nm
Measurement Points: 1001

Excellent Performance

Accurate measurement of optical modules requires an optical spectrum analyzer with excellent optical performance (wavelength range: 600 to 1750 nm, minimum resolution setting: 30 pm, good wavelength accuracy, linearity, and level accuracy). Moreover, supporting both single-mode fiber (SMF) and multimode fiber (MMF) helps customers requiring tests of optical transceivers, such as SFP and QSFP modules used in optical networks, as well as tests of 850-nm VCSELs and DFB light sources, etc., built into optical transceivers.

Anritsu MS9740B, Optical Transceiver
Optical Transceiver
Anritsu MS9740B, VCSEL and DFB-LD
VCSEL and DFB-LD Evaluation

Ideal for MMF VCSEL Evaluation

With a wavelength measurement range of 600 to 1750 nm, the MS9740B covers both single-mode and multimode applications. As well as supporting wavelengths used by communications, such as 1310 and 1550-nm SMF, the all-in-one MS9740B can also measure short wavelength bands used by MMF.
Connection losses at evaluation of 850-nm band VCSEL modules are minimized by input to MMF to assure efficient measurement of device characteristics while maintaining good optical sensitivity and high-speed sweeping at level and SMSR measurements. This supports optimum evaluation of optical devices using MMF input, such as VCSELs.

Anritsu MS9740B, Device Characteristics Evaluation
Example of Device Characteristics Evaluation
Anritsu MS9740B, VCSEL Spectrum Measurement
Example of 850 nm VCSEL Spectrum Measurement

Supports Optical Pulse Measurement Under Asynchronous Conditions Without Trigger Signal Input

With production of high-bit-rate LDs supporting recent deployment of high-speed networks, thermal countermeasures at LD chip production have become an issue in both communications and non-communications fields. There is increasing demand for spectrum measurement using pulsed optical input as a solution to this issue.
High-output CW LD chips suffer wavelength spectrum drift and decreased power level due to thermal effects.

Example 1 – Spectrum change due to LD chip temperature increase
Example 2 – Spectrum change due to LD chip temperature increase

Example of spectrum change due to LD chip temperature increase

Optical pulse measurement suppresses the impact of this phenomenon by adjusting the repetition frequency and Duty ratio to control the LD chip temperature.

Controlling LD chip temperature using pulse driving
Controlling LD chip temperature using pulse driving

However, generally, accurate measurement of an optical pulse signal requires synchronization with an input trigger signal. Unfortunately, when using this method, the slow seep speed compared to CW measurement, which does not require this synchronization, causes trigger-signal input related measurement difficulties, especially with tact times at manufacturing and inspection.
By using the MS9740B optical pulse measurement mode (Opt-020), the LD pulsed optical spectrum can be measured in about the same time as CW optical spectrum measurement under asynchronous conditions without trigger signal input. When using this mode, the important SMSR evaluation also achieves a high measurement reproducibility of ±1.4 dB*.

With MS9740B-020

* With MS9740B-020.
±1.8 dB with Multimode Fiber Interface MS9740B-009 installed
Using SM fiber and DFB-LD with 1550 nm wavelength at 10 dBm peak power input, with 45 dB max SMSR and no change in polarization conditions
Pulse conditions: 5 kHz min repetition frequency and 1% min Duty, Pulse Mode enabled, 1 kHz VBW, 0.1 nm Setting Resolution, 10 nm max span, 501 sampling points, at 23C°±5°C

Supports Various Optical Modules

Measurement methods and items differ according to the type of optical module when evaluating the optical spectrum of optical devices, making an optical spectrum analyzer with measurement modes for each optical module type very convenient.

The MS9740B has various measurement applications required for evaluating active optical devices (LD-Modules, DFB-LDs, FP-LDs, LEDs, WDMs, Optical Amplifiers (NF and Gain)) and supports all-at-once measurement of key evaluation items, such as center wavelength, level, OSNR, spectrum width, etc., on production lines. Analysis results are displayed on-screen for at-a-glance confirmation by operators for fast evaluation of individual optical devices.

Application Test
DFB-LD Spectrum evaluation of single longitudinal mode oscillation laser
FP-LD Spectrum evaluation of laser with multiple discrete oscillation wavelengths
LED Spectrum evaluation of wideband light source
PMD Evaluation of PMD characteristics of optical fiber cable
Opt. Amp
Opt. Amp (Multi-channel)
Evaluation of fiber amplifier (EDFA) Gain and NF characteristics
WDM Spectrum evaluation of WDM signal with up to 300 wavelengths (channels)
LD Module Evaluation of characteristics of optical transceivers, etc.
WDM Filter Analysis of optical bandpass filters

DFB-LD, FP-LD, LED: Analysis of Light-Emitting Elements

DFB-LD (distributed feedback laser diode), FP-LD (Fabry-Perot laser diode), and LED (light emitting diode) measurement items can be measured all at once with easy-to-understand on-screen display for more efficient evaluation.

DFB-LD Measurements
The DFB-LD is a single-spectrum semiconductor laser diode. It is commonly used in high-speed, long-distance communications applications due to its low optical-signal wavelength variation and small optical-signal waveform deterioration. The following items are measured for DFB-LD applications.

  • Peak: Peak wavelength and peak level
  • 2nd Peak: Side-mode wavelength and level
  • Kσ: Spectrum width using RMS method
  • SMSR: Side-Mode Suppression Ratio
  • Mode Offset: Offset between side-mode and peak wavelengths
  • Stop Band: Offset between both-side wavelengths of peak wavelength
  • Center Offset: Offset between peak wavelength and mean of both-side mode wavelengths
  • σ:Standard Deviation
  • ndB Width: Spectrum width at set cut level

Anritsu MS9740B, DFB-LD Test
Example of DFB-LD Test

FP-LD Measurements
The FP-LD is a semiconductor laser with multiple longitudinal oscillation modes in the spectrum. They have a wide application range for optical-disk (DVD, BD) pickups, laser printers, laser pointers, etc. The following items are measured for FP-LD applications.

  • Peak: Peak wavelength and peak level
  • Mean Wl: Center wavelength
  • FWHM: Spectrum width measured by RMS method (2.35 σ)
  • Total Power: Total power of spectrum
  • Mode (dB): Longitudinal oscillation mode count
  • Mode Spacing: Longitudinal oscillation mode gap
  • σ: Standard deviation of spectrum measured using RMS method

Anritsu MS9740B, FP-LD Test
Example of FP-LD Test

LED Measurements
The LED is a light-emitting element with a continuous spectrum. Due to the low power consumption and very long life, LEDs are being used recently for lighting applications and automobile headlamps. The following items are measured for LED applications.

  • Peak: Peak wavelength and level
  • Mean Wl (n dB): Center wavelength measured using ndB Loss method
  • Mean Wl (FWHM): Spectrum half-width center wavelength
  • ndB Width: Spectrum width measured using ndB Loss method
  • FWHM (2.35 σ): Spectrum half-width measured using RMS method
  • PkDens (/1 nm): Maximum spectrum density
  • Total Power: Total power in spectrum
  • Kσ: Spectrum width measured using RMS method
  • σ: Standard deviation of spectrum measured using RMS method
Anritsu MS9740B, LED Test
Example of LED Test

PMD: Optical Fiber Cable Polarization Mode Dispersion Measurements

Polarization Mode Dispersion (PMD) causes the optical pulse width to become wider as optical pulses pass through optical fiber and optical parts due to differences in propagation speeds caused by two polarization modes.

Anritsu MS9740B, PMD

The PMD measurement function measures the Differential Group Delay due to the time difference between polarization components.

Anritsu MS9740B, PMD Test
Example of PMD Test

Opt. Amp/Opt. Amp Multichannel: Evaluation of Fiber Amplifier (EDFA) Gain and NF Characteristics

The Gain and Noise Factor (NF) can be calculated automatically from the optical fiber amplifier (EDFA) input optical spectrum and output optical spectrum using three built-in types of measurement method (pulse, level interpolation, and polarization nulling).

Anritsu MS9740B, EDFA Test

Additionally, both WDM signals and the latest IEC-recommended Opt. Amp (Multichannel) applications are supported

  • Supports IEC-recommended ISS (Interpolated Source Subtraction) method for Gain and ASE analysis
  • New mode for detecting noise position automatically
  • Built-in Gain Variation and EDFA Output Slope analysis application
Anritsu MS9740B, Fiber Amplifier Test
Example of Fiber Amplifier Test

WDM: Evaluation of WDM Signal Spectrum for up to 300 Waveforms (Channels)

With a wide dynamic range of better than 58 dB (±0.4 nm from peak wavelength) and a higher resolution of 30 pm, the MS9740B can be used to evaluate high-speed, large-capacity, multiplexed optical WDM signals (100 GHz, 50 GHz spacing) in a fiber cable carrying many different optical wavelengths simultaneously.

Anritsu MS9740B, Evaluation of WDM Signal Spectrum

Key data for WDM signal analysis, such as center wavelength, level, SNR, etc., can be analyzed for up to 300 channels at once. Separation between channels can also be confirmed when switching to the Table display mode.

Anritsu MS9740B, WDM Wavelength
Anritsu MS9740B, WDM Test Result

LD Modules: Evaluation of Optical Transceiver, etc., Characteristics

Combining the MS9740B with Anritsu’s MP2110A (all-in-one instrument incorporating bit error rate tester and sampling oscilloscope) supports simultaneous BER, Eye Pattern, and optical spectrum measurements at evaluation of optical transceivers, such as SFP and QSFP28 modules.

Anritsu MS9740B, Evaluation of Optical Transceiver

At optical-transceiver spectrum measurement, all key test items required for evaluating active optical devices (center wavelength, optical level, OSNR, etc.) are displayed as a group on one screen for at-a-glance understanding of results.

Anritsu MS9740B, LD Modules: Evaluation

WDM Filters: Analysis of Optical Bandpass Filters

Optical bandpass filter characteristics can be evaluated efficiently by measuring signal level, peak signal number, signal wavelengths, spacing (wavelength), passband, and ripple, using the WDM Filter analysis function.

Anritsu MS9740B, WDM Filters: Analysis of Optical Bandpass Filters


Optical Spectrum Analyzer (OSA) MS9740B
Optical Spectrum Analyzer (OSA) MS9740B  Optical Spectrum Analyzer

The benchtop Optical Spectrum Analyzer MS9740B features wide dynamic range, high resolution, and fast sweep speeds. It supports multimode fiber input and is ideal for manufacturing and evaluating 850-nm band VCSEL modules.

BERTWave™ MP2110A100G/400G BERT, Sampling Oscilloscope

The Anritsu BERTWave MP2110A integrates a 4ch BERT and 4ch sampling oscilloscope in one measuring instrument. It is the ideal solution for BER measurements and NRZ/PAM4 EYE pattern analyses of 25/100/200/400G optical modules and devices.

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