Analog Circuit Design

16

A thermoelectric cooler temperature controller for fiber optic lasersClimatic pampering for temperamental lasers

Jim Williams

Introduction

Continued demands for increased bandwidth have resulted in deployment of fiber optic-based networks. The fiber optic lines, driven by solid state lasers, are capable of very high information density. Highly packed data schemes such as DWDM (dense wavelength division multiplexing) utilize multiple lasers driving a fiber to obtain large multichannel data streams. The narrow channel spacing relies on laser wavelength being controlled within 0.1nm (nanometer). Lasers are capable of this but temperature variation influences operation. Figure 16.1 shows that laser output peaks sharply vs wavelength, implying that ...