Photonic crystal nanocavity assisted rejection ratio tunable notch microwave photonic filter

Abstract

Driven by the increasing demand on handing microwave signals with compact device, low power consumption, high efficiency and high reliability, it is highly desired to generate, distribute, and process microwave signals using photonic integrated circuits. Silicon photonics offers a promising platform facilitating ultracompact microwave photonic signal processing assisted by silicon nanophotonic devices. In this paper, we propose, theoretically analyze and experimentally demonstrate a simple scheme to realize ultracompact rejection ratio tunable notch microwave photonic filter (MPF) based on a silicon photonic crystal (PhC) nanocavity with fixed extinction ratio. Using a conventional modulation scheme with only a single phase modulator (PM), the rejection ratio of the presented MPF can be tuned from about 10 dB to beyond 60 dB. Moreover, the central frequency tunable operation in the high rejection ratio region is also demonstrated in the experiment.

Recent Trends and Advances of Silicon-Based Integrated Microwave Photonics

“…A summary of silicon-based IMPF demonstrations since 2014 until mid-2018 is shown in Table 1, targeting to meet key performance metrics, such as high rejection ratio, high selectivity, wide frequency tunability, low power consumption, and low footprint. Many of these approaches have been mainly based on single micro-resonators [49,61,[105][106][107][108][109][110][111][112][113], in either of ring, disk or ultra-compact photonic crystal nanocavity shapes. A few, however, have focused on more elaborated designs involving more than one micro resonator or incorporating Mach-Zehnder interferometers (MZIs) [114][115][116][117].…”

“…A few works also have investigated the use of other photonic devices such as nanowires, photonic crystal MZIs, optomechanical cavity-waveguides, and WBGs [50,[118][119][120][121][122][123]. Representative results from one micro-resonator can be found in [61,[105][106][107][108][109][110]. These MPF proposals share the same operation concept, shown in Figure 12.…”

“…In both schemes, a microwave signal is first modulated on a signal optical carrier, and then processed by a resonator and detected by a PD. However, the modulation format determines the bandpass or bandstop (notch) nature of the MPF [61,[105][106][107][108][109][110]. To be specific, in Figure 12b, we first assume that an RF signal is modulated onto an optical carrier (CW light) of frequency f s by the phase modulation technique.…”

“…Hence, with the optical-to-RF mapping, a bandpass MPF with a central frequency of would be achieved, as shown in Figure 15b. Note that, however, in practice micro-resonators introduce a non-ideal, non-zero phase outside As mentioned above, two general mechanisms have been employed in the reported IMPFs to tune the frequency of the MPFs [61,[105][106][107][108][109][110]. The primary mechanism is to tune the optical carrier wavelength (changing the source wavelength) with respect to the resonance wavelength of the micro-resonator (see Figure 16a).…”

On-chip silicon photonic signaling and processing: a review

“…However, devices based on the aforementioned material platforms have relatively large footprint, and are lack of abilities for massive integration. The development of silicon photonics offers the possibility to perform photonic signal processing on an ultracompact silicon chip [54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71][102][103][104][105][106][107][108][109][110][111][112][113][114]. Silicon-on-insulator (SOI) platform is quite suitable for linear photonic signal processing for its low loss and ultracompact footprint.…”