Experimental demonstration of dissipative sensing in a self-interference microring resonator

Abstract

The dissipative sensing based on a self-interference microring resonator composed of a microring resonator and a U-shaped feedback waveguide is demonstrated experimentally. Instead of a frequency shift induced by the phase shift of the waveguide or the microcavity, the dissipative sensing converts the phase shift to the effective external coupling rate, which leads to the change of linewidth of the optical resonance and the extinction ratio in the transmission spectrum. In our experiment, the power dissipated from a microheater on the feedback waveguide is detected by the dissipative sensing mechanism, and the sensitivity of our device can achieve 0.22 dB/mW. This dissipative sensing mechanism provides another promising candidate for microcavity sensing applications.

Multi-Parameter Sensing in a Multimode Self-Interference Micro-Ring Resonator by Machine Learning

“…Figure 1a shows the schematic diagram of the SIMRR proposed in [26], where the upper and lower coupling regions (denoted by the alphabets 'U' and 'L' in Figure 1a) are connected by a U-shaped sensing arm waveguide. As described in our previous works [27,28], a tiny phase change induced by the sensing arm waveguide or microring waveguide adjusts effectively the effective coupling strength between the waveguide and microring, and then makes a significant change in the resonant wavelength and transmission depth of a transmittance dip. Consequently, as the analyte is only exposed to the sensing arm waveguide or microring waveguide, the proposed single mode intensity sensing is realized by measuring the change of transmission depth in a single resonant mode.…”

“…When the length change l of the sensing arm waveguide is adjusted, the SIMRR exhibits completely different wavelength dependent responses. Figure 1c is the enlarged diagram of Figure 1b in the wavelength range from 1442 nm to 1449 nm, where two transmittance dips are present near 1443 nm and 1448 nm at a fixed value of l. With the increasing of the induced length change l, the resonant wavelengths of transmittance dips are slightly shifted, and simultaneously their transmission depths are significantly varied, where the latter has been exploited to realize intensity sensing in a single resonant mode [26][27][28]. However, it is observed that their transmission depths do not show a monotonous change with l, and the single mode intensity sensing cannot be realized within the range of −10 nm ≤ l ≤ 10 nm.…”

“…Alternatively, when WGM resonators detect absorptive target analytes, the probe light may be strongly absorbed and then the linewidth of WGM resonator mode is significantly broadened, which is exploited to implement the dissipative sensing [16,20]. Lately, without the limitation of near-field interaction, a special intensity sensing has been presented in special waveguide-coupled WGM resonators [25][26][27][28].…”

“…In our previous works, the intensity sensing was exploited twice based on a microring resonator coupled with the sensing arm waveguide, which is called a self-interference microring resonator (SIMRR) [26][27][28]. The SIMRR sensor is designed only by exposing the target to be detected to the sensing arm or microring waveguide instead of the whole SIMRR structure.…”

“…The SIMRR sensor is designed only by exposing the target to be detected to the sensing arm or microring waveguide instead of the whole SIMRR structure. An induced tiny phase change of the sensing arm or microring waveguide mode is converted to a change of external effective coupling strength between the input waveguide and the microring waveguide, which then eventually leads to a significant change in the transmission depth, which is measured to realize the intensity sensing [26][27][28].…”