High-frequency characterization of high-speed modulators and photodetectors in a link with low-speed photonic sampling

We propose a low-speed photonic sampling for independent high-frequency characterization of a Mach–Zehnder modulator(MZM)and a photodetector(PD)in an optical link.A low-speed mode-locked laser diode(MLLD)provides an ultrawideband optical stimulus with scalable frequency range,working as the photonic sampling source of the link.The uneven spectrum lines of the MLLD are firstly characterized with symmetric modulation within the interesting frequency range.Then,the electro-optic modulated signals are down-converted to the first Nyquist frequency range,yielding the self-referenced extraction of modulation depth and half-wave voltage of the MZM without correcting the responsivity fluctuation of the PD in the link.Finally,the frequency responsivity of the PD is self-referenced measured under null modulation of the MZM.As frequency responses of the MZM and the PD can be independently obtained,our method allows self-referenced high-frequency measurement for a high-speed optical link.In the proof-of-concept experiment,a 96.9 MS/s MLLD is used for measuring a MZM and a PD within the frequency range up to 50 GHz.The consistency between our method and the conventional method verifies that the ultra-wideband and self-referenced high-frequency characterization of high-speed MZMs and PDs.

Optical A/D Quantizer Scheme Based on Parallel Phase Mod ulators

A high-speed and high-resolution optical A/D quantizer is proposed.Its architecture is discussed.Bit circuits are built by using the phase modulators in parallel.Based on the different character of the half-wave voltage for every phase modulator and the polarized bias design of incident light,the RF input signal is coled and transmitted in the form of optical digital signal.According to the principle of the architecture,the high-resolution quantizers with 8-bit and 12-bit,et al.are built,which operate at 100 GS/s.Their quantization noise is invariable almost with bit circuits increasing.The simulation result of 4-bit A/D quantizer is also given.

Optical Analog-to-digital Conversion Scheme Based on Tunable Fabry-Perot Resonator

Proposed is an interference type of optical analog-to-digital conversion(ADC). The refractive index of Fabry-Perot cavity changes with different voltages. The Fabry-Perot resonator converts electronic intensity into light wavelength through selecting lights of different wavelengthes. The parameters of the scheme are acquired with the transmission matrix of optical element and the time of steady-state light field. The maximum sampling speedes of 4-bit, 6-bit, 7-bit, 8-bit and 9-bit(ADC) are 1.695×1010 count/s, 4.33×109 count/s, 2.38×109 count/s, 1.24×109 count/s and 5.9×108 count/s, respectively.

An X-and Ku-band multifunctional radar receiver based on photonic parametric sampling

We demonstrate a novel multifunctional radar receiver scheme based on photonic parametric sampling.The working principle of photonic parametric sampling based on four-wave mixing(FWM)process is presented.To experimentally verify the multifulctional feasibility,the scheme is individually implemented to carry out a four-channel phased array radar reception and a dual-band radar reception.

Photonic Analog-to-Digital Conversion of Time-Continuous Signals using a TDM Switching-Wavelength Sampling Source

A 20 Gsample/s photonic analog-to-digital converter is constructed using a 4-switching-wavelength repetitive sampling pulse source. The signal-to-noise and distortion ratio (SINAD) is measured to be 44.5 dB and corresponds to 7 effective number of bits.