Introduction

Abstract

The field of modern telecommunications is being rapidly transformed by megatrends in three underlying core technologies: microelectronics, photonics, and software. In the field of microelectronics, advances in materials, design methodologies, high-resolution photolithography, and fabrication processes have produced high-gate-count very large scale integration (VLSI) circuitry characterized by ultrahigh reliability and capable of performing highly sophisticated functions at fast, real-time clock speeds. Submicron complementary metal oxide semiconductor (CMOS) technology permits single-chip custom integration approaching an equivalent count of one million gates if the circuit pattern is regular (e.g., memories, certain types of packet switches) and can be operated at a clock speed of 100–200 MHz. Emitter coupled logic (ECL), while not permitting as high a degree of integration as CMOS, can operate at clock speeds approaching 1 GHz with moderate functional complexity and even higher speeds with further-reduced functional complexity. Gallium arsenide (GaAS) technology, while not as mature as CMOS and ECL silicon technology, is capable of operating at clock speeds in excess of 10 Gbit/sec. These capabilities, in turn, have had profound impact on the fields of consumer and military electronics, computers, and telecommunications.