Abstract

Low cost, compact and robust single mode semiconductor laser diodes emitting at λ 1.6–2.1 μm are highly desirable as light sources for trace gas spectroscopy and an increasing number of other applications, such as, high data-rate communications over hollow core photonic crystal fibre, noninvasive optical blood glucose monitoring. Indium phosphide based light sources provide a solid and flexible base for mid-infrared semiconductor diode lasers. This chapter provides an overview of the current state of the art in discrete mode InGaAs/InP long-wavelength quantum-well lasers emitting in the 1.6–2.1 μm wavelength range. The discrete mode laser is essentially a regrowth free modified ridge waveguide Fabry-Pérot laser whose optical spectrum has a single wavelength mode. High-performance and costeffective mid-infrared DM laser diode sources are well suited to a wide range of sensor applications. The current state of the art will also be outlined in this chapter.

Keywords: semiconductor laser, mid-infrared sources, single mode laser, strained quantum-well, absorption spectroscopy
