Spectrometer

A spectrometer comprising:

• a substrate;
• a first layer of small-gap semiconductor material formed on the substrate;
• a first stack of layers comprising a plurality of large-gap semiconductor layers and small-gap semiconductor layers formed on the first layer of small-gap semiconductor material;
• a second layer of small-gap semiconductor material formed on the first stack of layers, wherein the first layer of small-gap semiconductor material, the first stack of layers and the second layer of small-gap semiconductor material form a luminous intensity detector for outputting an electrical signal as a function of an input light signal;
• a second stack of layers comprising a plurality of large-gap semiconductor layers and small-gap semiconductor layers formed on the second layer of small-gap semiconductor material, wherein the second stack of layers comprises first and second layers of small-gap semiconductor materials with respective first and second small-gaps of different values;
• and
• a third layer of small-gap semiconductor material formed on the second stack of layers, wherein the second layer of small-gap semiconductor material, the second stack of layers and the third layer of small-gap semiconductor material form a luminous intensity modulator having a range of modulation wavelength adjusted by a control signal, and for receiving a light signal and retransmitting a modulated light signal to the luminous intensity detector as the input light signal.