Semiconductor Ring Lasers for All-Optical Processing
Semiconductor ring and disk lasers (SRLs) have become an intense subject of research because of the rich variety of dynamics that is originated by the coexistence of two counter-propagating modes inside the same optical cavity. Of particular interest to practical applications is the strong lasing bistability that typically occurs between the clockwise or counterclockwise direction . When the SRL emits in a given direction, the external injection of a counter-propagating optical signal may stably reverse the emission direction of the device to the other direction. This behaviour makes the SRL a perfect all-optical Flip-Flop with very fast switching speed, small footprint, low switching energy and a unique potential for monolithical integration .
We exploited the all-optical bistability of SRLs to demonstrate all-optical flip-flop operation , optical logic gates (AND, OR and NOT), optical thresholders, signal regeneration and retiming , fast wavelength tunability  and integrated master-slave configurations .
From a technological and design viewpoint, large radius devices (i.e. R>100 μm) are now very well understood and have reached the performance and maturity of Fabry-Perot laser cavities. However, issues such as substrate losses, mode instabilities, thermal management, non-radiative recombination and power extraction become critical when the radius of the devices approaches a few tens of microns and below. We have been developing several device designs and technological processes to improve the performance and robustness of bistable SRLs with radii as small as 5 μm that operate CW and emit several mWs of optical power .
We are also exploring in more depth the potential for integration of SRLs to form complex optical networks. In fact, a circular optical cavity offers an ideal geometry for the flexible design of monolithically integrated coupled architectures with arbitrary and controllable coupling, cavity size, geometry or shape.
- Marc Sorel
- Michael Strain
- Gabor Mezosi
- Sandor Furst
- University of Bristol (Siyuan Yu, K. Thakulsukanant, B. Li, I. Memon, Z. Wang, C. Born)
- Universita’ di Pavia (Guido Giuliani, A. Trita, M. Zanola)
- Universitat de les Illes Balears (Salvador Balle, A. Scire’)
- Vrije University (Jan Danckaert, L. Gelens, S. Beri, G. Van Der Sande, G. Verschaffelt)
- Sorel, M, Laybourn, PJR, Giuliani, G, and Donati, S (2002) Unidirectional bistability in semiconductor waveguide ring lasers. Applied Physics Letters, 80 . pp. 3051-3053. (doi:10.1063/1.1474619)
- Mezosi, G., Strain, M.J. , Furst, S., Wang, Z., Yu, S., and Sorel, M. (2009) Unidirectional bistability in AlGaInAs microring and microdisk semiconductor lasers. IEEE Photonics Technology Letters, 21 (2). pp. 88-90. ISSN 1041-1135 (doi:10.1109/LPT.2008.2008660)
- Thakulsukanant, K., Li, B., Memon, I., Mezosi, G. , Wang, Z.R., Sorel, M. , and Yu, S.Y. (2009) All-optical label swapping using bistable semiconductor ring laser in an optical switching node. Journal of Lightwave Technology, 27 (6). pp. 631-638. ISSN 0733-8724 (doi:10.1109/JLT.2008.927755)
- Li, B., Memon, M.I., Mezosi, G. , Wang, Z.R., Sorel, M. , and Yu, S.Y. (2009) Characterization of all-optical regeneration potentials of a bistable semiconductor ring laser. Journal of Lightwave Technology, 27 (19). pp. 4233-4240. ISSN 0733-8724 (doi:10.1109/JLT.2009.2023087)
- Furst, S., Yu, S., and Sorel, M. (2008) Fast and digitally wavelength-tunable semiconductor ring laser using a monolithically integrated distributed Bragg reflector. IEEE Photonics Technology Letters, 20 (23). pp. 1926-1928. ISSN 1041-1135 (doi:10.1109/LPT.2008.2005000)
- Memon, M.I., Mezosi, G. , Li, B., Lu, D., Wang, Z.R., Sorel, M. , and Yu, S.Y. (2009) Generation and modulation of tunable mm-wave optical signals using semiconductor ring laser. IEEE Photonics Technology Letters, 21 (11). pp. 733-735. ISSN 1041-1135 (doi:10.1109/LPT.2009.2017383)
Mezősi, Gábor (2011) Semiconductor ring lasers for all-optical signal processing. PhD thesis, University of Glasgow
EPSRC GR/S63533/01: RAPTOR - Rapidly tuneable semiconductor ring laser
FP6-2005-IST-5: IOLOS - Integrated Optical Logic and Memory using ultrafast Micro-ring bistable Semiconductor Lasers