Diode laser bars
	Single chips consist of a single emitter and are usually used in telecommunication products,
	e.g. for signal transmission or in consumer products, e.g. CD players. For the use in high-
	power diode lasers, several emitters such as illustrated in are united to a so-called laser
	diode bar. Theoretically, it would also be possible to mount several single chips onto one
	heat sink each and to integrate them on a single common mechanical base.
	Today, laser diode bars are used almost exclusively due to the simplified handling and the
	higher precision of the spatial arrangement of the single emitters obtainable with bars.
	Fig.2 Laser diode bars
	In a bar, the individual emitting areas (emitters) lie side by side and, together with the non-
	emitting areas between the emitters, they form the so-called active layer. Emitters may have
	the form of strip arrays or wide strips.
	The number, the width and the spacing of the emitters are dependent on the manufacturer.
	The relative value of the emitting areas in the active layer with respect to the bar width is called
	filling factor (FF). Typical filling factors are 30...90%.
	The center-to-center distance between two adjacent emitters is called pitch.
	Z is the propagation axis of the laser radiation. The propagation axis Y is called fast axis (FA),
	the propagation axis X is termed slow axis (SA). This is connected with the beam angle
	(divergence) in the two planes, XZ and YZ