Frequency shifting in multimode fiber optic phase modulation devices
Abstract
The possibility of shifting the frequency of modulation signals in a multimode light guide by exploiting internal interference phenomena is demonstrated. Two modes of conversion of phase modulation to amplitude modulation in the same multimode light guide are investigated: differential phase modulation and interference between light beams passing through the light guide and rereflected from its ends. An expression is derived for the amplitude of a differential modulated signal. Phase modulation of coherent radiation in a fiber optic light guide is found to be a parametric process. When two modulators operate simultaneously, the spectra of the differential phase modulation and signal echo contain combination frequencies because of the parametric conversion. Parametric frequency conversion is useful for developing heteodyne and frequency multiplexing devices.
- Publication:
-
USSR Rept Electron Elec Eng JPRS UEE
- Pub Date:
- October 1984
- Bibcode:
- 1984RpEEE.......49P
- Keywords:
-
- Fiber Optics;
- Frequency Shift;
- Modulators;
- Phase Modulation;
- Amplitude Modulation;
- Coherent Radiation;
- Heterodyning;
- Multiplexing;
- Electronics and Electrical Engineering