MEMS gratings for wavemeters and tunable light sources
Abstract
A review of three different systems based on the MEMS tunable blazed grating technology is presented. A MEMS tunable blazed grating is a versatile optical element providing a compact tunable mechanism for optical systems. The MEMS chip measures 5x5 mm2, including a position encoder, and is shock resistant up to 3000 g. The grating can operate in different spectral regions (Visible to Mid-IR) and high optical throughput is guaranteed at all wavelengths by operating it in Littrow condition. The first system shown uses the MEMS grating in a compact wavemeter. It is tested as Fiber Bragg Grating interrogating system. At 1.5 μm wavelength, it detects lines as narrow as 0.2 nm, resolves lines 2 nm apart and retrieves the central wavelength with accuracy better than 20 pm. By using the position encoder the expected accuracy can be on the order of 1pm. The second system shown demonstrates a compact (<10 cm3) tunable external cavity Quantum Cascade Laser using the MEMS grating. The resulting laser operates at a center wavelength of 9.5 μm and is tunable over a range of 150 nm. Finally a double stage monochromator is presented. Two MEMS chips with different grating periods are cascaded, in order to cancel out undesired grating orders, and to improve the filter linewidth (~1nm) and the extinction ratio (26 dB). The cascaded filter can be combined with a broadband source to select an arbitrary wavelength in the 400-800 nm range or the 800-1600 nm range.
- Publication:
-
Reliability, Packaging, Testing, and Characterization of MOEMS/MEMS and Nanodevices XII
- Pub Date:
- March 2013
- DOI:
- 10.1117/12.2000530
- Bibcode:
- 2013SPIE.8614E..08T