The Study On All-Optical Information Processing Based On Saturable Absorber Laser

As the tendency of future communication,optical communication networks are gaining increasing interests.Optical-electronic-optical(OEO)mode,which has been widely used in optical communication networks for a long time,is gradually replaced with all-optical networks due to the bottleneck of OEO in efficiency and power consumption.Semiconductor laser diode(LD),of which distributed feed back LD and distributed Bragg reflector LDs are implemented more for optical information processing,is an important component of all-optical networks.Recently,studies on novel external cavity semiconductor lasers,including saturable absorber laser,are attracting more attention.Based on the preceding background and related basic theory,this paper will focus on the following two new applications of saturable absorber laser in all-optical information processing:(1)One of the suitable ways to achieve the data rate of 400Gb/s that individual channels are required to have in future networks is to use multiple carriers of low baudrate combined in an overall superchannel.In this paper,the performance of all-optical wavelength conversion of Nyquist-WDM superchannels is investigated.This paper considers advanced modulation formats of DQPSK and 16-QAM for the subchannel modulation format achieving raw bit rates of 448Gb/s and 896Gb/s respectively.The simulation result demonstrates the wavelength conversion of Nyquist-WDM superchannel using degenerate and non-degenerate four-wave mixing in a saturable absorber laser.The study in this paper considers the effects of raised cosine and root raised cosine signal pulse shaping within the wavelength conversion process.The performance of the converted superchannels is found to be severely impaired by crosstalk due to cross-gain modulation of the pump by the superchannel.Optimum performance of the converted channel is achieved by setting the detuning between the continuous-wave pump and the central wavelength of the superchannel to be around 200GHzand using pumps of double the gain saturation power of the saturable absorber laser with 23dB pump to signal power ratio.(2)Based on the basic theory of saturable absorber laser,this paper proposes a low latency optical switch based on the saturable absorber laser implemented on chip multiprocessors for two scenarios:multiple-socket shared memory coherence network and optical top-of-rack switches for data centers.The switch architecture uses a control plane with a simplified send and forget server interface and the use of a.hybrid Mach-Zehnder interferometer and saturable absorber laser integrated optical switch with electronic buffering.Study results show that the proposed architecture offers some reduction in head latency at low loads compared with a conventional scheduled optical switch as well as offering increased performance of the chip multiprocessors.However,the performance of power consumption needs more investigation in the future to be optimized.