Figure 1: Microspectrometer with access waveguides and diffraction grating.
PARTNER INSTITUTION: Concordia University
BACKGROUND
The possibility to acquire a spectrum is determinant in sensing for the accurate detection of biological and chemical species, their discrimination, their quantification, and possibly simultaneous identification. In the same time, hand-held devices are desired for easy, fast, and ubiquitous detection. On-chip integrated spectrometers provide an answer to these requirements, as they offer a small foot-print, are cheaper to manufacture and more robust (no moving or assembled parts). These devices are expected to be significantly more present in the near future. Additional uses include telecoms and microelectronics, notably with silicon photonics. A high spectrometer efficiency is desired to minimize optical losses, which for detectors translates into a higher sensitivity.
TECHNOLOGY
The invention is a new type of diffraction grating for planar integrated optics, which separates the different wavelengths spatially.
- Monolithic spectrometer/demultiplexer using an elliptical Bragg mirror concave diffraction grating.
- Non-metallic, no deep etching.
- Single fabrication step possible.
COMPETITIVE ADVANTAGES
- Small foot-print.
o Smaller size, lower cost, higher yield/reliability, more channels.
o Reduction of size ~ 8× vs AWG, or more when many channels.
- High efficiency.
o Theoretical efficiency: -0.14 dB (97%), the highest for concave diffraction grating spectrometers.
o Higher sensitivity (for sensor), specific applications with low light levels (photon counting).
- Lower polarization-dependent loss (PDL).
- Simplified fabrication (no deep etching, no metal).
- Well suited for silicon photonics.
APPLICATIONS
- Integrated sensors (biophotonics, gas sensor, etc.).
o Detection of biological & chemical species (identification, quantification, multiple detection).
- Miniature spectrometers (stand-alone, optical coherence tomography, etc.).
o Hand-held devices desired for easy, fast, ubiquitous detection.
- Optical interconnects for microelectronics.
- Wavelength-division multiplexing for optical telecommunications.
TECHNOLOGY DEVELOPMENTAL STAGE
First device fabricated and tested:
- Efficiency of -3.0 dB (includes all internal spectrometer losses).
- Channel uniformity: 0.4 dB (over 30 nm).
- Crosstalk of 15 dB.
- These values can be enhanced (as done for other spectrometers) by, e.g., optimization of coupling back to output waveguides (not done so far).
- Potential to achieve theoretical performance.
PATENT STATUS
Pending.
BUSINESS OPPORTUNITY
- An patent-pending technology that is available through Aligo Innovation.
- A licensing opportunity for co-developing the technology into a commercial grade product.
- A unique opportunity to address the fast growing Spectrometer, Sensor and DWDM markets.
Figure 2: Details of silicon photonics microspectrometer.
Keywords: Integrated optics, on-chip, spectrometer, waveguide, diffraction grating, sensor,
lab-on-a-chip, optical interconnects, wavelength-division multiplexers (WDM).