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Principal Sponsors:
 | Dense Wavelength Division Multiplexing (DWDM) Testing |
4. The Optical Spectrum Analyzer
Although by its very nature the laboratory-based optical spectrum analyzer meets the new testing requirement for measurements as a function of wavelength, present-day OSA versions are entirely unsuited to field use. Large and heavy, laboratory OSAs are not packaged for portability. The sophisticated optics they contain make them extremely vulnerable to shock and in frequent need of realignment and recalibration. Their proper use requires a high degree of operator skill. All in all, laboratory OSAs are the antithesis of a good candidate for field use (see Figure 3).
Producing an OSA that is small, rugged, and reliable enough to be carried about in the field and to be operated by technicians lacking extensive experience with laboratory OSAs is a challenge whose resolution involves the following three steps:
- eliminating the features and capabilities of laboratory instruments not required for the maintenance of DWDM networks (e.g., spectral measurement abilities outside the EDFA wavelength region)
- selecting and developing an optical configuration that can withstand shock and operate without the delicate mechanical displacements used by conventional single-pass and double-pass monochromater designs (see Figure 4)
- simplifying the traditional, complex, laboratory-oriented user interface to accommodate the needs of the field operator
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