Experiment Optical multiplexing

This practical work covers the key points of a complete optical telecommunications system chain:
- its emission (modular laser sources),
- a means of transmission (optical fiber),
- its reception (photodiodes)
- two different wavelength multiplexing and demultiplexing systems (with diffraction gratings and dichroic filters).

Subjects discussed :
- Transmission of a signal optically
- Wavelength multiplexing
- Wavelength demultiplexing

Principles and objectives:
- Transmission of a signal optically:
Modular laser diodes are used to carry a signal. Since the sources have different wavelengths, it is possible to combine them at the fiber input (multiplexing) and separate them at the ouExperimentut (demultiplexing).
- Wavelength multiplexing:
A diffraction grating deflects the beam from the red laser diode at a different angle than the blue laser diode. This property is used to inject the two signals into the same fiber. It is also possible to simply use the large numerical aperture of the fiber to directly inject the beams from the 2 laser diodes with adequate incidence.
- Wavelength demultiplexing:
At the ouExperimentut of the fiber, the same diffraction grating makes it possible to angularly separate the signal carried by the red light from that carried by the blue source. Another method is to use blue and red colored filters to isolate and separate the signals.

Composition :
▪ 1 optical honeycomb table 600x450 mm (ref.203268)
▪ 8 single magnetic feet (ref.202542)
▪ 2 magnetic feet with lateral adjustment (ref.202707)
▪ 1 modular red laser (ref.201004)
▪ 1 modular blue laser (ref.204598)
▪ 2 SFH-300 phototransistors
▪ 3 simple component holders (ref.202439)
▪ 2 fiber supports with SMA Clix bases on rod (ref.204727)
▪ 1 thin blade holder on rod (ref.202448)
▪ 1 Paton network 600 lines/mm (ref.202343)
▪ 2 converging lenses, f= + 50 mm (ref.202273)
▪ 2 dichroic filters: yellow and blue (ref.204023+204020)
▪ 1 SMA plastic fiber – 2 m (ref.202729)
▪ 1 experiment note