On our recent trip to China, we took the opportunity to go to Nanjing to visit Nanjing CQ Laser Technology. It is named after CQ Xu, the chairman, who is also a professor at McMaster University in Toronto.
Mr. Xu’s work in laser began with the development of periodically poled lithium niobate (PPLN) waveguide materials. By creating the right separation between the electrodes, an incoming laser wavelength can be converted to a higher frequency using a second harmonic generation process. In the case of Nanjing CQ Laser, they use a commercially available 808nm laser diode to generate green laser light at 532nm for projection applications, along with other wavelengths for a variety of needs.
Their facility consists of 400K square meters of workspace where they manufacture 200K chips/year. This production started with just the MgO doped PPLN chip. Xu said that MgO:PPLN chips and modules have much higher conversion efficiency and lower cost compared to KTP or LBO options for example. Production is done on 3” wafers that result in usable PPLN devices with over 90% yield.
The next step for the company was to make what they call their mGreen module. This consists of the MgO:PPLN and a NdY4 laser crystal packaged together in a sealed device. “This module makes the production of green laser much easier as the tricky alignment part is done in the module and sealed,” said Xu. “All one needs to do is add an 808 laser diode as the pump laser to get green laser light without having to do active (live laser light) alignment.”
With this complete, the company now offers a complete green laser device as well. Nanjing CQ Laser focuses on high power green lasers for use in projection applications today. Lasers are offered in 1.5 to 4W power levels. Ganging multiple lasers together and fiber optically coupling them allows projection systems with high lumen output to be assembled. Tens of optical green Watts are need for home theater projectors and hundreds needed for cinema projectors.
The company also buys red and blue laser die and packages them into higher power laser modules with red (638 nm) at 600-700mW and blue (457 nm) in 1.4W and 2.5W versions.
On our facilities tour, we saw a special demo being put together for the following week for their investors, which includes the Nanjing Economic Development Zone and other independent investors. Modules of blue, green and red light were shown as well as a home theater projector prototype. This consisted of a Barco projector that had the lamp removed and RGB laser light coupled in over multi-mode fiber (photo). The company has its own proprietary despeckling technology too. Images looked quite speckle-free with bright, saturated colors.
We saw an Epson projector being worked on with a 40W RGB engine and a Barco Cinema projector project is underway too that will feature a 300W RGB engine. Future development will also look at creating A 6p RGB laser solution.
Nanjing CQ laser is a laser company, so it is working with partners to build up these projector demonstrators to showcase their lasers. We will be checking back with them from time to time to see how they are getting on. – CC
