Renyuan Wang

High Linearity InP-Based Phase Modulators Using a Shallow Quantum-Well Design

Phase modulator nonlinearity is a major problem for implementing an optical phase-locked loop (OPLL) phase demodulator. In this letter, we report an improved InP phase modulator design that uses a detuned shallow multiquantum-well structure. The phase modulator shows high linearity and low optical loss. Its phase IP3 and optical loss per unit length are ~ 4 π/mm and ~ 0.9 dB/mm, respectively. This phase modulator design is thus suitable for implementing the OPLL linear phase demodulator.

Design and Fabrication of S 0 Lamb-Wave Thin-Film Lithium Niobate Micromechanical Resonators

Commercial markets desire integrated multifrequency band-select duplexer and diplexer filters with a wide fractional bandwidth and steep roll-off to satisfy the ever-increasing demand for spectrum. In this paper, we discuss the fabrication and design of lithium niobate (LN) thin-film S0 Lamb-wave resonators on a piezoelectric-on-piezoelectric platform. Filters using these resonators have the potential to fulfill all the above requirements. In particular, we demonstrated one-port high-order S0 Lamb-wave resonators with resonant frequencies from ~400 MHz to ~1 GHz on a black rotated y-136 cut LN thin film. The effective electromechanical coupling factor (k2eff ) ranges from 7% to 12%, while the measured quality factor ranges from 600 to 3300. The highest k2eff × Q achieved on this chip is 194, significantly surpassing contour mode resonators manufactured in other technologies.

A Monolithically Integrated ACP-OPLL Receiver for RF/Photonic Links

The first monolithically integrated optical phase-locked loop (OPLL) employing attenuating-counter-propagating waves is presented. It demonstrates the highest dynamic range among monolithically integrated OPLLs. Its performance is limited by the bandwidth and linearity of the photodetectors used in the OPLL.

High k t 2 ×Q, multi-frequency lithium niobate resonators

This paper presents design and vacuum measurements of lithium niobate (LN) contour-mode resonators (CMR). By carefully positioning the interdigital transducer (IDT), we achieved CMRs with k_t²×Q of 7%*2150=148 (IDT @ node) or resonators with very high k_t² of 12.3% and spur-attenuated response (IDT @ anti-node). In addition, we demonstrated resonators with frequencies ranging from 400MHz to 800MHz on a single chip.

Thin-film Lithium Niobate contour-mode resonators

This paper presents Lithium Niobate (LN) thin-film contour mode resonators (CMR) on a piezoelectric-onpiezoelectric platform. Using this platform, we demonstrate, on a black Y136 cut Lithium Niobate thin-film, one-port high-order width extensional contour mode resonators at 463MHz and 750MHz. The electro-mechanical coupling factor (k_t²) and quality factor (Q) of the 750 MHz resonator is 8.6% and 612, resulting in a k_t²*Q of 53. The 463MHz resonator exhibits a k_t²*Q of 105, with a 7% k_t² and 1500 Q. With this technology, we can potentially achieve multi-frequency band-pass filters with both wide bandwidth and steep roll-off.

Dual-Polarization Spatial-Hole-Burning-Free Microchip Laser

We propose a novel spatial-hole-burning-free dual-polarization Nd : YAG microchip laser lasing at 1064 nm. The device has been experimentally investigated. Stable dual-polarization operation was observed.

Novel Phase Modulator Linearity Measurement

Phase modulator linearity is an important concern for high dynamic range phase modulated optic links. However, the determination of phase modulator linearity is difficult as it requires an optical phase demodulator that generally contains nonlinear distortion that tends to contaminate the measurements. In this letter, we present a simple and effective approach for phase modulator linearity measurement that can be made into a photonic integrated circuit and does not require a reference linear phase modulator. We also present the measurement results.

Efficient RF Frequency Down-Conversion Using Coupled Quantum-Well Optical Phase Modulator

Frequency down-conversion is important to radar front-end. In this work, we achieve efficient RF frequency down-conversion using a coupled quantum-well optical phase modulator fabricated on an indium phosphide material platform. When used in conjunction with an optical phase-locked loop-based linear phase demodulator, a 1-mm-long device exhibits a down-conversion loss of ~2.6 dB and a spurious-free dynamic range of ~125 dB·Hz2/3 in the photodetector shot-noise limit. Furthermore, the phase modulator has a very low optical propagation loss (<;0.2 dB/mm). This allows for a longer modulator device capable of achieving even higher performance.

Quadratic Electrooptic Effect for Frequency Down-Conversion

A novel optical frequency down-conversion approach employing the quadratic electrooptic effect is proposed, analyzed, and verified. This down-conversion method can seamlessly integrate with an optical phase-locked-loop linear phase demodulator. It has the potential to achieve a large dynamic range and low conversion loss. Comprehensive theoretical studies are performed to investigate the noise, efficiency, and linearity of this down-conversion approach. Experiments are then conducted. It is found that the unwanted fourth-order electrooptic effect of the InP modulator device limits the dynamic range.

RF frequency down-conversion with quadratic electro-optic effect

The frequency down-converter is an essential element of a photonic radar frontend. In this paper we describe a new photonic frequency down-conversion approach employing a quadratic optical phase modulator. When paired with an OPLL linear phase demodulator, this approach can potentially achieve a large dynamic range and a low conversion loss. A preliminary experiment has been performed to verify frequency down-conversion with an InP MQW optical phase modulator. It has been found that the unwanted 4th order electro-optic effect that exists in phase modulator results in spurious distortion for the down-converted RF signal. The techniques for mitigation are discussed.