Optimization Design Of Polymer Optical Switch/Router And Development Of Its Measurement System

Electro-optic (EO) switches and optical routers play a crucial role for improving theperformances of optical communication systems. Over the past several years, along with agrowing number of research groups, one can witness an unprecedented explosion in the field ofoptical switches and optical routers. Microring resonators (MRRs) have some excellent featuresincluding compactness and possibility of dense integration, therefore they have been widely used.Besides, Poled polymer materials can be widely used in the fabrication of optical switches andmodulators, because of their high EO coefficient, fast response speed, easy control of refractiveindex, and simple processing technology. Boxlike-spectrum polymer electro-optic switch andpassive—optical router are optimized and designed by combining the advantages of polymermaterial and microring resonator. Dynamic/Static measurement systems of optical switch aredeveloped. The main contents of the work are as follows.1. Cross-coupling electro-optic(EO) switches based on single-group one microring,single-group seven microrings, single-group2N+1microrings and double-group2N+1microrings are optimized and designed. Firstly, the switch based on single-group one microringis designed, waveguide core size is optimized, and the spectral characteristics and switchingcharacteristics are analyzed. Secondly, for realizing boxlike output spectrum, electro-optic(EO)switches based on single-group seven microrings and single-group2N+1microrings areoptimized and designed. The relationships between the characteristics of the optical switches andN are analyzed. The results show that when the central coupling gap between channel waveguideand MRR waveguide is0.14and between two adjacent microrings is0.68,the crosstalkand the insertion loss of the switch are almost the smallest. For obtaining <30dB crosstalkunder through-state, the dependency of switching voltage on N is determined as7.19×exp(N/0.72)+1.72(V). In order to obtain lower than10dB insertion loss under both states, theparameter N should be less than10. Under the operation voltages of0V (drop state) and thepredicted switching voltages (through state), the device performances are analyzed. The crosstalkof the ten devices (N=110) are <19.5dB and the insertion losses of the ten devices (N= 110) are <9.715dB under drop state. The crosstalk of the ten devices (N=110) are <28.7dB and the insertion losses of the devices (N=110) are <1.573dB under through state. Thedevice also has ultra-compact footprint size of only0.331.06mm. Finally, electro-optic (EO)switches based on double-group2N+1microrings are optimized and designed, which haveboxlike output spectrum. When N increases from1to5, the insertion losses of five devices arealmost identical (~0.24dB) and the crosstalk decreases dramatically from28.2for N=1to134.2dB for N=5under through state. The insertion loss of five devices rises from1.40dB to5.12dB and the crosstalk firstly drops and then increases with a variation range of51103dBunder drop state.2. Device architecture and design scheme of passive optical router with scalable channelwavelengths are proposed. Firstly, Basic cross-coupling two-microring resonator routing elementbased on polymer materials is optimized for single-mode transmission, low optical loss andphase-match between microring waveguide and channel waveguides. Secondly, a one-stagefour-port optical router is constructed using four-group basic routing elements, which has12possible I/O routing paths and3channel wavelengths. The insertion losses of each channelwavelength along every routing path are within the range of0.02~0.61dB, the maximumcrosstalk between the on-port along each routing path and other off-ports is less than39dB,and the device footprint size is~0.13mm2. Aiming at wideband signal routing applications, wethen construct a universal N-stage cascaded polymer four-port optical router possessing scalable3N channel wavelengths. Finally, Using eight-group basic elements, a new one-stage five-portpolymer optical router is proposed, and it can optically route four channel wavelength. Theinsertion losses along all routing paths are within0.030.62dB, the maximum crosstalk of allrouting operations is less than39dB. At the same time, we construct a universal N-stagecascaded polymer five-port optical router possessing scalable4N channel wavelengths.3. Dynamic/static measurement systems of optical switch are developed. In order to measurethe performance of the optical switch, using ARM7processor and InGaAs photoelectric detector,measurement system for optical switch was developed. Optical power meter is mainly composedof photoelectric detector, preamplifier, signal regulator, AD converter, main controller, displaymodule, etc. The system was calibrated with the help of a commerical optical power meter, andits zero drift is found to be smaller than0.5dBm. the output optical power from one port of theswitch was both measured by the self-developed optical power meter and the commerical powermeter. The experimental results show that, the obtained two curves have the same variation trend.This shows that the measurement system has good performance and can meet the needs of the actual measurement.Lock-in amplifier is composed of photoelectric detector, preamplifier, signalregulator, reference signal generator, AD630multiplier circuit, low-pass filter circuit, the addercircuit, the sample hold circuit, the AD converter circuit.The max error is smaller than5%of thelock-in amplifier. The system provides a solution for the performance measurement of the opticalswitch due to its small size and high performance-cost ratio.The novelties of this thesis are as follows.(1) Cross-coupling electro-optic(EO) switches based on single-group2N+1microrings anddouble-group2N+1microrings are optimized and designed. The relationships between theswitches characteristics and N are analyzed. When N takes the appropriate value, the outputnon-resonant light is suppressed and the device has boxlike output spectrum, lower crosstalk andlower insertion loss.(2) A one-stage four-port and a one-stage five-port optical routers based on polymer materialsare optimized and designed. Aiming at wideband signal routing applications, we construct auniversal N-stage cascaded polymer four-port optical router possessing scalable3N channelwavelengths and a universal N-stage cascaded polymer five-port optical router possessingscalable4N channel wavelengths.(3) Dynamic/static measurement systems of optical switch are developed.The output opticalpower from one port of the switch was both measured by the self-developed optical power meterand the commerical power meter. The experimental results show that the obtained two curveshave the same variation trend. The system provides a solution for the performance measurementof the optical switch.