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Abstract Hybrid photodetectors with 2D materials and quantum dots (QDs) offer new opportunities for spectral detection given their high mobilities and spectral tunability, respectively. Herein, the study presents a novel architecture of alternating PbS QDs with graphene monolayers positioned at different depths and with independent contacts. This geometry enables the probing of the photocurrent depth profile and therefore of different spectral bands. The study realizes devices with up to five graphene layers and five QD layers intercalated, using only one type of QDs (Single‐Bandgap devices) with an exciton absorption peak at 920 nm, as well as devices with different types of QDs (Multi‐Bandgap devices) with exciton peaks at 850, 1190, and 1350 nm. Since the absorption depth and photoresponse is wavelength dependent, each graphene has a different spectral response, which opens the path for spectral analysis. As expected, it is observed that top graphene layers have stronger response than deeper graphene layers, especially for short wavelengths. However, for the case of Multi‐Bandgap devices, a negative photoresponse coefficient is even observed for longer wavelengths, showing stronger response for deeper layers than for top layers. This intercalated architecture can be used for compact multispectral photodetection without any diffractive or beam splitting component. 

Abstract Phase‐sensitive integrated photonic devices are highly susceptible to minor manufacturing deviations, resulting in significant performance inconsistencies. This variability has limited the scalability and widespread adoption of these devices. Here, a major advancement is achieved through continuous‐wave (CW) visible light (405 and 520 nm) trimming of plasma‐enhanced chemical vapor deposition (PECVD) silicon‐rich nitride (SRN) waveguides. The demonstrated method achieves precise, bidirectional refractive index tuning with a single laser source in CMOS‐compatible SRN samples with refractive indices of 2.4 and 2.9 (measured at 1550 nm). By utilizing a cost‐effective setup for real‐time resonance tracking in micro‐ring resonators, the resonant wavelength shifts as fine as 10 pm are attained. Additionally, a record red shift of 49.1 nm and a substantial blue shift of 10.6 nm are demonstrated, corresponding to refractive index changes of approximately 0.11 and −2 × 10⁻². The blue and red shifts are both conclusively attributed to thermal annealing. These results highlight SRN's exceptional capability for permanent optical tuning, establishing a foundation for stable, precisely controlled performance in phase‐sensitive integrated photonic devices. 

Lithium niobate on insulator (LNOI) waveguides, as an emerging technology, have proven to offer a promising platform for integrated optics, due to their strong optical confinement comparable to silicon on insulator (SOI) waveguides, while possessing the versatile properties of lithium niobate, such as high electro-optic coefficients. In this paper, we show that mode hybridization, a phenomenon widely found in vertically asymmetric waveguides, can be efficiently modulated in an LNOI ridge waveguide by electro-optic effect, leading to a polarization mode converter with 97% efficiency. Moreover, the proposed device does not require tapering or periodic poling, thereby greatly simplifying the fabrication process. It can also be actively switched by external fields. Such a platform facilitates technological progress of photonics circuits and sensors.