The application of silicon photonic technologies to
optical telecommunications requires the development of near-infrared detectors
monolithically integrated to the Si platform. Most present approaches require
the bonding of the semiconductor detector material to the silicon circuitry,
which can be time consuming and expensive. While approaches to integrate Ge with
Silicon have also been explored, the direct absorption edge of pure Ge falls in
the middle of one of the infrared optical communications windows, and provides
poor absorption (hence optical signal detection) in the other two optical
communication wavelength bands.
To address these issues, researchers at ASU have developed
infrared detectors using Germanium-Tin (GeSn) materials that may be grown with
high crystalline quality on Si substrates. The researchers have demonstrated
prototype p-i-n detectors based on Ge0.98Sn0.02 with an extended infrared
absorption that covers all three telecommunications wavelength bands, and higher
optical absorption characteristics than Ge.
Potential Applications
- Long, medium and short-distance telecommunications:
detectors integrated directly with silicon will reduce costs and may also
reduce power consumption of receiver modules for apps such as Fiber to the
Home and Ethernet
- Optical interconnects: parallel arrays of photodetectors
integrated with silicon could be used to achieve ultra-fast data transfer
between and within microchips
- Infrared detectors for instrumentation: Detectors could
replace materials such as pure Ge and InGaAs in instrumentation and
measurement settings
Benefits and Advantages
- Detectors are integrated directly on Si using
low-temperature CMOS-compatible conditions
- Extended optical absorption response over the entire C-,
L- and U- bands for telecommunications (IR detection to at least 1750 nm,
beyond 1550 nm usually offered by Ge)
- Higher optical absorption, when compared to Ge
Download
Original PDF
