| 摘要 |
PROBLEM TO BE SOLVED: To raise a distance resolution and to enlarge a dynamic range. SOLUTION: This device is provided with a signal light source 1, an optical multiplexer/demultiplexer 3, a light receiving device 5, an addition processor and a display device 7. The signal light source 1 is a light source for generating signal light pulses whose wavelength is changed by a prescribed wavelength interval at every prescribed time interval within the pulse width time of the signal light pulses and an optical delay circuit 8 for supplying prescribed optical delay for the respective wavelengths is provided in front of the light receiving device 5. Also, instead of the optical delay circuit 8, the light receiving device 5 may be provided with the optical multiplexer/demultiplexer 3 for demultiplexing light for the respective wavelengths, photodetectors for independently converting rear part scattered light and reflected light for the respective wavelengths to electric signals, a delay circuit for supplying prescribed delay to the electric signals from the respective photodetectors and an addition circuit for superimposing the electric signals of the rear part scattered light and the reflected light for the respective wavelengths from the delay circuit. |
