Development of high power laser technology: 915 nm mini-bars for fibre laser pumping and red laser bars for cinema/projector applications

The development of high power 915 nm mini-bar semiconductor laser chips are becoming important sources of low cost pump power for fibre laser systems. In this paper we demonstrate improvements in 915 nm single emitter laser power and report initial test and reliability data for five emitter mini-bars designed for operation up to 40W. Additionally we describe the development of high power 635nm broad area single emitters and laser bars chips for application as red source in laser cinema.

I. Introduction

Fibre lasers are becoming increasingly important sources for industrial processing applications due to their compact, efficient and flexible nature. The market for fibre lasers is estimated to be anywhere from $450 million to$1.4 billion per annum depending on the commentator and is set to grow by 10–20% per annum over the next few years. It has been reported that 915nm high power laser diodes can operate at telecoms chip reliability levels but at powers of over 10W per emitter [1], making them suitable sources of power for fibre laser pump applications. The cost of these pump laser diodes for a fibre laser is extremely significant (60%-70%) so a reduction in $/Watt is of vital importance. In this paper, we report the development of a ‘mini-bar’ [2] laser diode chip at 915nm as a potential integrated source for a reduced cost, compact, combined emitter fibre laser pump module.