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Measurements Applications
Measuring Coherence Length
Measuring Coherence Length
Coherence length is a measure of the distance over which a laser’s light retains the
phase relationships of its spectrum. The Keysight 86120B measures coherence
length of Fabry-Perot semiconductor diode lasers. The Keysight 86120B cannot
measure coherence length of light emitting diodes (LEDs) or distributed feedback
(DFB) lasers.
When you select coherence length measurements, the Keysight 86120B displays the
following four values:
• Coherence length (Lc)
• Round trip optical length of diode laser cavity (2nLd)
• Alpha factor
• Beta factor
Coherence length in the region of 1 mm to 200 mm can be measured. The following
figure shows a coherence length measurement.
To measure coherence length
1
Press the front-panel Preset key.
2
Press Appl’s and then
COH LEN
.
Summary of Contents for 86120B
Page 1: ...Keysight 86120B Multi Wavelength Meter User s Guide...
Page 2: ......
Page 3: ...1...
Page 12: ...10 General Safety Considerations...
Page 68: ...You can use the ABORT and CONT softkey to stop and restart a print job that is in progress...
Page 100: ...98 Programming Monitoring the Instrument...
Page 231: ...229 Performance Tests Test 5 Amplitude Accuracy and Linearity...
Page 232: ......
Page 244: ...242 Specifications and Regulatory Information Product Overview...
Page 250: ...248 Reference Menu Maps Display List by Power Menu Display List by WL Menu...
Page 251: ...249 Reference Menu Maps Delta On Menu Delta Off Menu...
Page 253: ...251 Reference Menu Maps System Print Menu...
Page 254: ...252 Reference Menu Maps System Setup Menu...
Page 272: ......