photonic integrated circuit abbr., PIC (rus. фотонная интегральная схема otherwise оптическая интегральная схема abbr., ФИС) — a multiple photonic device, fabricated on a flat substrate and processing optical signals.

Description

Photonic integrated circuits (PICs) contain multiple optically interconnected components, fabricated on the same substrate and jointly performing various functions of processing optical signals (typically in the visible or near infra-red wavelength ranges). PICs are expected to play a crucial role in the development of optical communication.

Devices with all components manufactured by introducing impurities or structurising the substrate material are called monolithic PICs. The common material for monolithic PIC substrates is GaAs or InP, termed as AIIIBV compounds, since they are composed of elements arranged in columns III and V of the periodic table. The devices which are produced on AIIIBV substrates use the impurities that control the band gap width and, thus, the operating wavelength of active devices - lasers and amplifiers.

Non-monolithic PICs are called hybrid PICs. They are usually made on substrates of lithium niobate, silicon, glass, as well as on polymeric substrates as a rare case. Lithium niobate is used as the substrate because of its high electro-optic coefficient. Silicon is a very promising material for PIC fabrication, as it makes it possible to use electronic integrated circuit technologies and, perhaps most importantly, combines photonic and electronic integrated circuits. Glass or plexiglass (polymethyl methacrylate) are low cost and widespread, besides, the production of lasers and amplifiers can be based on some glass types doped with rare earth elements.

However, such materials usually fail to be used in monolithic device production, since some functional devices (for example, semiconductor lasers) are easier to glue than integrate into the substrate material.

PIC production technology is similar to electronic IC production technology, where photolithography is used to mark the substrate for etching and material deposition as needed. To date, PICs are most commonly used in optical communication systems.

Reconfigurable I/O multiplexers for optical communication systems are an example of photonic integrated circuit applications, as they replaced the multiplexers based on discrete elements. Another example of a PIC widely used in optical communication systems is the optical transmitter where a single chip integrates its basic components: a semiconductor distributed feedback laser, an electro-optical modulator and a semiconductor amplifier.

PICs enable the production of more compact and higher performance optical systems (as compared with systems based on discrete optical components) and make it possible to integrate them with electronic circuits to miniaturise multifunctional optical-electronic systems and devices.

Authors

  • Razumovsky Alexey S.
  • Nanii Oleg E.

Sources

  1. M. Young. Optics and Lasers: Including Fibers and Optical Waveguides (Advanced Texts in Physics). — Springer; 5th completely rev. and enlarged ed. edition. 2000 — 528 p.
  2. Welch D., Joyner C., Lambert D. et al. III–V photonic integrated circuits and their impact on optical network architectures // Optical Fiber Telecommunications / Ed. by I. P. Kaminow, T. Li, A. E. Willner. — Academic Press, 2008. P. 343–379.
  3. Photonic integrated circuit // Wikipedia, the free Encyclopedia. — http://en.wikipedia.org/wiki/Photonic_integrated_circuit (reference date: 12.10.2009).

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