Page 300 - High Power Laser Handbook

268 So l i d - S t at e La s e r s Heat-Capacity Lasers 269

Figure 11.2 84 kW, 560-bar diode array manufactured by Simmtec. 5

A detailed view of the structure of a 10-bar tile is shown in Fig. 11.3,
which shows the relative relationship among all the major compo-
nents of a diode package, as well as the sophistication of the design.
Many processing steps, from etching the coolant passages in the glass
block to accurately positioning and soldering the actual diode bars to
the etched silicon submount, are required to make this sophisticated
device.
Figure 11.4 shows a graph of output power versus current into
the diode bars for quasi-continuous wave (QCW) operation. Approx-
imately 2 kW of peak output power is achieved at a drive current of
140 amps, with an electrical-to-optical efficiency of 55 percent. These
10-bar tiles are “burned in” for a period of 12 continuous hours at
165 amps and a 20 percent duty cycle, which is well in excess of the
nominal operating parameters and which ensures the desired perfor-
mance under safe and robust operation.
The second critical hardware component of the HCL is the laser
gain medium. The advent of large, transparent ceramics as laser gain
media is a key technological advancement in development of the