We successfully completed the development of a GaN based Tunable laser for Tapestry holographic data storage through
collaborative research with InPhase Technologies in 2010. After the collaborative research, with the aim to achieve
further advance development for commercial storage use, we have continued to improve the laser characteristics,
especially coherence property and high optical output power are significant issues for holographic data storage.
Longitudinal single mode lasing is one of most important property in hologram recording; therefore we addressed to
optimize laser diode structure for external cavity laser.
In parallel to that, we have reviewed not only a Laser diode structure but also laser drive processing, and have
successfully developed a function. In the case of performing high visibility hologram recording, prior to exposing to
medium, both the laser driving current and the wavelength are slightly adjusted to achieve single mode lasing. We call
this function “Mode Stabilizer”. Mode Stabilizer can automatically execute the adjustments in combination with an
internal mode sensor for visibility sensing. This function is advantageous in that erroneous page-recording can be
Moreover, we achieved high optical output power of 100 mW increased from conventional 45 mW, by optimizing the
device structure of GaN Laser diode. With this high optical output power, acceleration of recording bit rate becomes