Multi-port C-band Tunable Wavelength Blocker Based On Digital Micromirror Device

With the wide application of dense wavelength-division multiplexing(DWDM)technology and the tremendous growth in optical fiber transmission capacity,existing electrical switching technologies have long been overwhelmed in terms of switching capacity and energy efficiency,and the next generation of intelligent full-light based on wavelength switching has been built.Communication networks have gradually become an important consensus in communications research and industry.The reconfigurable optical add/drop multiplexer(ROADM)and multi-dimensional optical cross-connect(OXC)devices that can be remotely controlled by software are crucial for the development of future all-optical communication networks.Value and broad international market demand.The ROADM can not only realize the intelligent and flexible configuration of existing network resources,but also can flexibly expand the network scale and services according to the needs.Wavelength Blocker(WB)is one of the ROADM key technologies.It is an optical system that can spatially block any communication wavelength flexibly.At present,the core technologies of wavelength blockers mainly include micro-electromechanical systems(MEMS),liquid crystals(LS),planar photonics(PLC)photonic integration technologies,and liquid crystal on silicon(LCOS)technologies.In recent years,as a mature spatial light modulator,digital micromirror devices(DMDs)are gradually expanding into the non-projection display field due to their advantages such as fast response speed,polarization independence,stable performance,and reasonable price.In this context,this paper proposes a multi-port C-band tunable wavelength blocker based on digital micro-mirror devices,and finally achieves a 16-port,100-GHz,channel-interval blocking function that can be flexibly controlled by remote software.The specific research work is as follows:1.Using scalar diffraction theory to analyze two types of DMD:The DLP5500(single pixel size 10.8 ?m)and 0.7" XGA(single pixel size 13.68 ?m)diffraction characteristics mainly analyze the effects of single-pixel size and incident angle on the DMD diffracted light distribution when coherent light is incident.The appropriate single-pixel size and angle of incidence are chosen to achieve a near-diffraction state with high diffraction efficiency.Theoretical analysis shows that the DLP5500(single pixel 10.8?m)achieves near-brilliance at the incident angle of 12°,the near-blink order is(-2,-2),the diffraction angle is-11.42°,and the diffraction efficiency of the array is 98%.At this time,the diffracted light and the incident light basically coincide;For 0.7" XGA(single pixel 13.68?m),the diffracted beam deviates from the blazed condition at an incident angle of 12°,four interference maxima occur,and it is difficult to return the original coupling into the fiber.At the incident angle of 52°,the near-bladder state is reached.The light level is(-2,-2),and the diffraction efficiency of the array is as high as 100%.2.The DMD model was constructed in optical software and applied to the analysis of DMD diffraction characteristics in optical systems.A multi-port C-band tunable wavelength blocker based on a 0.7" XGA model DMD was designed and fabricated.The structure of the system is optimized in the software.3.Based on the theoretical analysis,a 16-port C-band wavelength blocker based on DMD was built to achieve blocking of any wavelength within the wavelength range of 1530 nm-1560 nm.The 16-port loss range is 12dB-15dB,where the loss is low at 1545nm,and the bandwidth edge causes higher loss due to the,diffraction angle problem.The reason for higher system loss is that the DMD model is not fully compliant,and the 7-9dB loss introduced by the DMD can be eliminated by selecting a more suitable model.Each port has good uniformity and crosstalk between channels is less than-35dB(no crosstalk).The blocking extinction ratio of each channel is-35dB,and effective wavelength blocking can be achieved.The tuning accuracy of the center wavelength is 5 GHz,the minimum channel spacing is 100 GHz,and the minimum tuning accuracy of the spectral bandwidth is 10 GHz.This work provides a theoretical basis and technical support for the subsequent development of more ports of wavelength blocker experimental prototype.