In order to reach faster speeds, laser diodes – the components that produce the light beam used to read and write data to and from the disk – need to become more powerful. The companies have developed such higher-power laser diodes, paving the way for 4x DVD-R, -RW, -RAM and +RW drives.
The new components can deliver 100 milliwatts in pulses, making them around 40 per cent more powerful than the 70-milliwatt versions used for 2x drives. This means data will be able to written to the disk at a rate of 44Mbps (megabits per second), speeding up the time taken to write a 4.7GB disk to around 14 minutes. Double-speed drives take twice as long and single-speed drives take almost an hour to carry out the same task.
Both companies will soon ship samples of the higher-power laser diodes – Sharp for $22 and Mitsubishi Electric for $37. They expect to begin commercial production in May or June at a rate of 100,000 diodes per month.
Sales of recordable and rewritable DVD drives are climbing fast, as the products drop in price. For example, the Matsushita DVD-RAM/DVD-R unit – reputedly employed by Apple in its SuperDrive – now costs $246 in Japan.
Sales are expected to jump from 1.3 million in 2001 to 9.8 million this year, according to analyst Jon Peddle, of Jon Peddle Research. He predicts drive shipments will surpass 50 million in 2005.
The next speed hike for rewritable DVD drives to 6x models, is not expected until sometime in 2003, when laser diodes capable of delivering 120 milliwatts will become available.