High-resolution Optical Vector Analysis Based On Double-sideband Modulation

Cutting-edge researches,such as ultrahigh-capacity optical communication,slow-light storage,and ultra-high-precision measurement,require optical devices and photonic integrated chips to have the ability to do with high-resolution multi-dimensional spectral parameters(including maglitude,phase and polarization).The multi-dimensional spectral response of these optical devices and photonic integrated chips should be finely measured in the process of development,production and application.At present,optical vector analysis(OVA)based on optical single sideband(OSSB)modulation is the only way to realize ultrahigh-resolution measurement of multi-dimensional spectral response of optical devices,but the method has the disadvantages of small measurement bandwidth,large nonlinear error and inability to measure band-pass devices.Aiming at these key problems,the OVA based on optical double sideband(ODSB)modulation is proposed and studied in this paper.The specific research works are as follows:The OVA based on ODSB modulation is proposed for the first time.Frequency-shifted optical carrier is used to realize asymmetric ODSB modulation.After photoelectric conversion,the responses information carried by two first order optical sidebands of the modulated signal are converted to two microwave signals respectively with different frequencies.The spectral responses on both sides of optical carrier can be obtained by microwave magnitude and phase detection.Compared with the traditional OSSB-based OVA,this method breaks through the limitation of the work bandwidth of optoelectronic devices and microwave devices in the measurement system,doubles the measurement bandwidth in one single-channel,and is immune to measurement errors introduced by the high-order sidebands.Three kinds of OVA based on ODSB modulation are proposed and experimentally demonstrated.The OVA based on acousto-optic modulator and asymmetric double sideband modulation can measure the magnitude response with high dynamic range and high signal-to-noise ratio,which is suitable for band-pass device measurement.OVA based on stimulated Brillouin scattering and asymmetric double sideband modulation can measure the magnitude and phase response simultaneously with large sideband suppression ratio,which leads to a suppressed enough residual sideband.OVA based on dualdrive modulator and asymmetric double sideband modulation can simultaneously measure the magnitude and phase response with a simpler structure and no significant distortions in the measurement results.In addition,the performance of the measurement system is studied in this paper.The influences on measurement precision by the residual sideband,the original carrier and the high-order sidebands of the asymmetric optical double sideband signal are studied by analytic analysis and numerical simulation.Key measurement performance improvement techniques are also proposed in this paper.Measurement bandwidth expanding technology based on optical frequency comb can achieve OVA with measurement bandwidth greater than 1THz.Common mode noise suppression technology can eliminate the light source power fluctuations and the measurement errors introduced by nonlinearity of electro-optical modulator.In this paper,novel schemes of the OVA based on ODSB modulation are proposed,theoretical analyzed and experimental demonstrated,which can achieve multi-dimensional,large measurement bandwidth,and high-precision measurement of spectral response of optical devices.It can obtain new datas of high-precision optical devices and innovative photonic integrated chips in the development and application,which strongly supports innovations and breakthroughs for cutting-edge research.