Optical spectrum analyzer: Insight into the world of light, driving innovation in multiple fields
Optical spectrum analyzer is the core tool of modern optical measurement. It can decompose complex optical signals into components of different wavelengths and accurately measure key parameters such as intensity, wavelength, and bandwidth. Its core principle is based on the dispersion of light (such as diffraction grating) or interference (such as Fourier transform spectrometer), which separates the incident light by wavelength space, and then uses a high-sensitivity detector array (such as InGaAs) to capture the optical power of each wavelength point, and finally draws an intuitive spectrum diagram. Taking the TFN AM7800 optical spectrum analyzer as an example, it adopts an advanced monochromator design, which significantly improves the ability to suppress stray light and ensures the purity and reliability of the measurement results.
AM7800: A powerful engine for professional optical spectrum analysis
AM7800 demonstrates the outstanding capabilities of modern high-performance optical spectrum analyzers:
Broad coverage and fine resolution: Covering the 600nm to 1700nm band (covering the O to L communication band and part of the visible light), supporting single-mode and multi-mode fiber input. 7 levels of resolution (0.02nm to 2nm) are provided, and users can optimize the choice between precision and speed as needed.
Excellent sensitivity and dynamic range: The sensitivity is as low as -90dBm (specific band) and the dynamic range is up to 75dB. This enables it to clearly separate weak signals from adjacent strong background noise, which is the key to analyzing dense wavelength division multiplexing (DWDM) systems and low-power light sources.
Ultra-high precision and stability: The wavelength accuracy is ±0.015nm (1520-1620nm), combined with the built-in wavelength calibration source, to ensure the repeatability of long-term measurements (±0.01nm/minute). Power accuracy is ±0.3dB (@1550nm, -20dBm), and linearity is ±0.08dB.
Intelligent operation and analysis: Equipped with a 10.1-inch touch screen, it supports multiple measurement modes such as CW light and pulse light. Provides powerful automated analysis functions, such as automatic peak/valley finding, OSNR (Optical Signal-to-Noise Ratio) calculation (formula: OSNR = 10 log10(Psignal / Pnoise)), EDFA noise figure (NF) measurement, SMSR (Side Mode Suppression Ratio) analysis, filter characteristics (passband, stopband, notch bandwidth) characterization, DFB/FP laser and LED spectrum analysis, etc.
Rich interfaces and system integration: Standard Ethernet, USB, GP-IB and other interfaces make it easy to build an automated test system to meet the high-efficiency needs from the laboratory to the production line.
Core application areas of optical spectrum analyzers
1. Optical communication R&D and manufacturing:
Laser/light-emitting device testing: Accurately measure center wavelength, spectrum width (FWHM/RMS), side mode suppression ratio (SMSR), mode spacing (FP-LD), and power stability. The high wavelength accuracy of the AM7800 is the key to ensuring that the device complies with the ITU-T wavelength grid.
EDFA (Erbium-doped Fiber Amplifier) testing: Measure gain spectrum, gain flatness, and noise figure (NF). The large dynamic range (75dB) and high sensitivity (-90dBm) of the AM7800 can accurately separate the signal from the ASE noise and calculate the in-band OSNR.
WDM/DWDM system testing: Analyze multi-channel wavelength, power, channel spacing, and the critical OSNR. The WDM analysis function of the AM7800 can automatically identify channels and calculate in-band/out-of-band OSNR, which is a powerful tool for system maintenance and fault location.
Passive device characterization: Measure the transmission spectrum, reflection spectrum, bandwidth (3dB, 20dB, 40dB, etc.), center wavelength, isolation, insertion loss, ripple, etc. of filters (such as WDM filters and gain flattening filters).
2. Fiber optic sensing system:
Analyze the reflection/transmission spectrum of sensors such as fiber Bragg gratings (FBGs) and long period gratings (LPGs), and monitor their center wavelength drift (corresponding to changes in physical quantities such as temperature and strain). The high wavelength accuracy and repeatability of AM7800 are crucial for such applications.
3. Material research and optical characterization:
Measure the emission spectra of fluorescent materials and phosphorescent materials.
Analyze the transmission/reflection spectral characteristics of optical films and crystals.
In combination with broadband light sources (such as supercontinuum SC light sources or superluminescent diodes SLDs), AM7800 can be used to measure gas absorption spectra (such as the gas mixture analysis mentioned in the article), and has potential in the fields of environmental monitoring and gas detection.
4. Scientific research and frontier exploration:
In the research of quantum optics, nonlinear optics, biophotonics, etc., it is used to accurately measure complex optical field characteristics such as ultrashort pulse spectra, frequency combs, and spectral broadening caused by nonlinear effects. The minimum sampling resolution of AM7800 (0.001nm) supports fine spectral structure research.
Application value: from precise measurement to industry empowerment
The application value of spectrum analyzers is far-reaching:
Guarantee quality and reliability: In the production of optical devices and modules, it is the final inspection point to ensure product performance and quality consistency. The high-precision parameter measurement of AM7800 is the cornerstone of product reliability.
Accelerate R&D and innovation: Provide key data support for the R&D of new light sources, optical amplifiers, and optical devices, and shorten the R&D cycle. Its powerful analysis functions (such as curve fitting and pattern analysis) help to deeply understand the physical mechanism of the device.
Optimize network performance and operation and maintenance: In the deployment and maintenance of optical communication networks, it is the core instrument for diagnosing link problems (such as OSNR degradation and nonlinear effects), evaluating system performance, and performing precise commissioning. The portability (relative to traditional instruments) and rich interfaces of AM7800 make it suitable for the field.
Promote multidisciplinary integration: As a bridge connecting optics with communications, materials, sensing, environment and other fields, it provides an indispensable measurement method for interdisciplinary research and emerging applications (such as LiDAR spectrum calibration and biomedical imaging light source characterization).
Conclusion
Spectrometers, especially modern instruments such as TFN AM7800 with wide band, high precision, large dynamic range and intelligent analysis capabilities, have become the "eyes" of the optoelectronics industry and cutting-edge scientific research. It is not only a basic tool for understanding the interaction between light and matter, but also a core engine driving the upgrade of optical communication networks, the birth of new optical devices, the development of advanced sensing technology and multidisciplinary integration innovation. Mastering spectral analysis technology means mastering the key to insight into the mystery of light and harnessing the light of information.