Indium Phosphide (inP) is the substrate material of choice for active optical components emitting or detecting light in the wavelength range from 1250 nm to 1620 nm, which comprises all commonly used wavelengths for fiber optic transmission over distances of more than a few hundred meters.

Components are manufactured by epitaxially growing a variety of binary (e.g. n-doped or p-doped InP), ternary (e.g. InGaAs) or quaternary (e.g. InGaAsP) semiconductor materials on the substrate, selectively etching away said materials and re-growing with different material compositions.

Through a sequence of etch and re-growth process steps, highly advanced active components can be built that integrate different functions: generation, filtering, tuning, amplification, modulation, and detection of light. State-of-the-art examples include tunable lasers with integrated amplifiers and/or modulators, arrays of lasers and modulators integrated with a wavelength multiplexer, or arrays of detectors integrated with a wavelength demultiplexer.