Lead Inventors:
Chee Wei Wong, Sc.D., Xiaodong Yang, James McMillan
All-Silicon Raman Lasers
Raman lasing, demonstrating record low threshold and high efficiency, have been increasingly studied. The Raman effect is widely used today to make amplifiers and lasers in glass fiber. However, silicon is more advantageous material because its bulk Raman gain coefficient is 10,000 times higher than in glass.
Recently, low-threshold continuous-wave all-silicon Raman laser has been demonstrated, which has greatly advanced the state of art. However, the demonstrated Raman laser has a relatively large effective modal area (1.6 um2). Also, a p-i-n diode structure is needed to minimize non-linear losses due to two-photon absorption (TPA) induced by free-carrier absorption (FCA) and to achieve low lasing threshold.
All-Silicon Raman Lasers Based on Micro-Ring and Micro-Racetrack Resonators
This technology presents methods and devices for all-silicon Raman lasers based on micro-ring and micro-racetrack resonators. The resonators used here typically have 10 times smaller effective modal area (~ 0.1 um2) and thus the surface area to volume ratio is higher and the effective free carrier lifetime is significantly reduced to below 1 ns. This allows the device to lase without an external p-i-n diode to drive the carriers away.
The lasing input-output characteristics and lasing threshold have been analyzed by coupled-mode theory framework. And, the enhancement of spontaneous emission, a pre-requisite for lasing, in micro-racetracks has been experimentally verified.
Applications:
• Can lead to practical applications as optical amplifiers, lasers, wavelength converters, optical computing and communications devices, and new kinds of lossless optical devices
• Can be used to develop silicon chips used in both electronic and photonic applications, to replace existing photonic devices made from expensive compound semiconductor materials
• Can be used to manufacture high-quality photonic devices and bring the benefits of low-cost, high-bandwidth silicon based optical devices to the mass market
• Low-cost all-silicon Raman laser can also be used to develop new medical, sensor, and spectroscopy devices. For example, this can be used to develop more affordable medical lasers with special wavelength used in dentistry.
Advantages:
• Develops Raman lasers based on micrometer resonators such as micro-ring and micro-racetrack
• Achieves more than 10 times smaller effective modal area (~ 0.1 um2)
• Reduces free carrier lifetime to below 1 ns, advancing the efficiency and applicability of all-silicon Raman laser devices
• Achieves Raman lasing without p-i-n diode or external biased voltage
• Allows lasing devices to be made of silicon, which is much cheaper than more exotic and expensive materials, such as indium phosphide and gallium arsenide
Patent Status: Patents Pending
Licensing Status: Available for Licensing and Sponsored Research Support
Related Cases: M05-049 (
US 2007/0025409 A1)
M05-004/M05-098 (
US 2006-0050744 A1 &
WO 2007/027982)