Yes, it is possible to send information using one wavelength of light at a time with different amplitudes. This principle forms the basis of various modulation techniques used in communication systems, such as Amplitude Modulation (AM) and Pulse Amplitude Modulation (PAM).
In Amplitude Modulation, the amplitude of a carrier wave is modulated or varied to encode the information. The variations in amplitude represent the information being transmitted. For example, in AM radio broadcasting, the audio signal (voice or music) is superimposed on the carrier wave by varying its amplitude. The receiver can then extract the original signal by demodulating the amplitude variations.
Similarly, Pulse Amplitude Modulation (PAM) encodes information by varying the amplitude of individual pulses in a pulse train. Different amplitudes can represent different symbols or data points, allowing the transmission of digital information. PAM is commonly used in digital communication systems like Ethernet.
By manipulating the amplitude of a single wavelength of light, such as in the case of fiber optic communication, it is possible to encode and transmit information. The varying amplitudes can represent different digital signals, allowing for high-speed data transmission.
It's worth noting that in modern communication systems, various modulation schemes are used, including not only amplitude but also frequency and phase modulation, to achieve efficient and reliable transmission of information.