Red Laser Diodes for New Application Fields Including Industrial and Medical Sensor and Display Light Source

TOKYO, JAPAN— October 5, 2006—Hitachi, Ltd., and Opnext, Inc., global leaders in state-of-the-art laser technology, have introduced the first low-operating current and high optical output power red laser diodes, HL6364DG, HL6365DG and HL6376DG (640nm wavelength band, 65mW optical output power) for use in industrial and medical sensor light source, measurement equipment and next-generation display applications.

Through the low-operating current, these products make it possible to lower the power consumption needed without sacrificing the 65mW high optical output power. In addition, these diodes extend the battery life for battery-powered equipment ultimately resulting in energy savings. Volume shipments of the HL6364DG, HL6365DG and HL6376DG begin in October 2006.

Laser diodes have features such as single wavelength lasing, directivity and a small size, making them ideal for digital information applications and use in the fiber optic communication field. Especially in the visible area of 800nm or shorter wavelength band, the wavelength band is being reduced for better visibility and high density optical disc equipment. Therefore, the 405nm wavelength band is in practical use today. The 630 to 640nm wavelength band laser diodes that have been developed are suitable for applications in laser levelers, distance meters, optical fiber checkers, and positioning
sensors such as chip mounters. Particularly, these laser diodes with the higher optical output are expected to be in high demand due to the number of available medical and display applications. Hitachi and Opnext are proud to offer a product with the lowest-operating current and highest optical output power of a 65mW red laser diode on the market.

“The Opnext HL6364DG, HL6365DG and HL6376DG offer the lowest operating current in 640nm wavelength band at 65mW optical output power,” explained Opnext Senior Vice President, Tadayuki Kanno. “This advance was achieved through a new process which includes a new waveguide structure and optimized structure parameter. The active layer thickness and facet reflectivity, results in a lower level of power consumption and extended battery driven time. These products make it possible to meet new application fields.”

In order to reduce the low operating current, the Multi-Quantum Well (MQW) *1 structure and wave-guide structure are optimized. Also, the aspect ratio*2 has been successfully improved from 3.5 to 2.1. Due to both the low operating current and aspect ratio, electrically driven products are then able to produce a higher optical output power with a lower operating current. The specification of operating temperature has kept 50 degree Celsius as the existing temperature. Therefore, it is possible to use the laser HITACHI diode under the same environmental conditions as utilized by previous products.
The HL6364DG, HL6365DG, and HL6376DG package is a standard size, 5.6mmφ, suitable for small-sized applications and selectable from three types of internal circuit which are anode common (HL6364DG), cathode common (HL6365DG), and cathode common for both LD and PD (HL6376DG). Also, the product provides a built in photodiode for monitoring laser output. This photodiode allows for easier control of the auto power circuit.
Moving forward, Opnext will continue to develop higher optical output power products.
The Company will also introduce a new lineup of laser diodes with low operating current, high optical output power, and low aspect ratio. Opnext is pleased to support new product development for applications in emerging technology fields.