Guided-wave and free-space optical interconnects for parallel-processing systems: a comparison

Abstract

Guided-wave and free-space optical interconnects are compared based on insertion loss, link efficiency, connection density, time delay, and power dissipation for three types of connection networks. Three types of free-space interconnect systems are analyzed that are representative of a wide variety of free-space systems: space-variant basis-set and space-invarient systems. Results indicate that the connection density of a space-variant free space system has a connection density roughly equivalent to a two level guided-wave system with a pitch of ~10 µm (for a 1-µm wavelength) and a core refractive index of 2.0. It is also shown that the connection density of basis-set and space-invariant free-space systems can be several orders of magnitude higher than fundamental limits on the connection density of dual-level guided-wave interconnect systems when large-scale highly connected networks are employed.

Demonstration of a 280 Gbit/s free-space space-division-multiplexing communications link utilizing plane-wave spatial multiplexing

“…For a free-space communication link over relatively short distances, like those used for optical interconnects, it has been shown that a transmitter array can be imaged on to a matched receiver array with a particular arrangement of lenses [6,7,8,9]. In 1996, one such system was demonstrated to work over 10 cm link length with a total link capacity of 1.6 Gbit/s [10].…”

Rationale and challenges for optical interconnects to electronic chips

“…Since that time, a body of work (see, for example, [4] and [6]- [33]) has addressed potential benefits and limits of optics for interconnection [4], [7], [8], [12], [14]- [16], [20], [23], [24], [28], analysis of the relative benefits of optics versus electronics [4], [6], [9]- [11], [13], [21], [22], [26], [27], [30], [31], [33], and comparison of different kinds of optical approaches against one another [17]- [19], [25], [29]. Several of these papers review parts of this work (e.g., [20], [22], [27], and [28]).…”

A new-generation parallel computer and its performance evaluation

“…Misalignment problems are solved gracefully in our design, as shown in this section. Free-space interconnects possess an energybandwidth product which is larger than their electronic counterpart [3].…”