Introduction
Intent
This test procedure defines and updates the methodology formeasuring the center (mean) wavelength, peak wavelength and thespectral width (rms1 ) of multilongitudinal mode (MLM),multitransverse mode (MTM), and single mode (SM) semiconductorlasers using a dispersive spectrophotometric method or othersuitable methods. For SM lasers, only center wavelength should beused and it should be noted that other spectral characteristics,such as Side Mode Suppression Ratio (SMSR), Stop Band (SB) fordistributed feedback (DFB) lasers for example, are not covered bythis document. Other measures of spectral width for MM lasers arealso retained from previous versions of this document. Recentstudies on the measurement of the optical spectrum from variouscoherent sources into multimode fiber have highlighted issues withmeasurement repeatbility due to speckle pattern variations andlaunch conditioning of the optical source into the multimodeoptical fiber. In addition, using multitransverse mode sources,such as some VCSELs, with singelmode optical fiber can lead toundersampling of the complete optical spectrum.
Hazards
This procedure involves potentially hazardous operations asdiscussed in this section. During the measurement, a laser may emitnon-visible light. Personnel are strongly cautioned never to lookdirectly into the laser or any fiber optic cabling at any time.Although the optical output power is generally not very high,virtually all the power is concentrated into a narrow frequencyband, which implies that the energy can be focused into a veryintense spot on the retina by the lens within the viewer’s eyes.For a complete review of laser safety guidelines, the reader isreferred to the international standard IEC 60825-2.
- Edition:
- A
- Published:
- 11/30/2006
- Number of Pages:
- 30
- File Size:
- 1 file , 370 KB
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