## 1 Introduction  
The semiconductor technology based on modern electronic integrated circuits is rapidly approaching their fundamental limits in terms of further transistors scaling and nanoscale elements' thermal budget. In addition, the electrical signal transmission rate between various elements limits the interconnects performance. One of the alternative technologies that could overcome the existing limitations and ensure further performance growth is optical interconnects (including plasmonic) [1]. The high optical frequency allows for dramatically increasing information transmission and processingrates. At the moment, there are two main approaches to optical interconnects design for a system in housing: multiplexed interconnects (where different optical signals are transmitted at individual frequencies using one common optical waveguide [2]) and non-multiplexed interconnects (where signals from each source are transmitted via individual optical waveguides [3]). One of the first implementations of optical interconnects was a rather cumbersome multiplexed scheme, proposed in 2001 by [PERSON]'s group [4]. In modern multiplexed optical interconnect schemes [5; 6], all bulky elements which connect waveguides and electronic microcircuits are replaced with dielectric waveguides and a dielectric multiplexer. Lens-free input/output systems based on integrated diffraction gratings were developed for optical waveguide coupling. However, despite the great progress in this field, the multiplexed scheme has a number of fundamental shortcomings. Firstly, diffraction grating-based input and output systems are speed-limited because of an increase in the transmission band leading to a decrease in power efficiency (growing scattering losses). Secondly, for the purpose of multiplexing signals from several sources, high-quality resonators are required. At the same time, excessively high-quality factors result in unfavorably high sensitivity to all the external influences, leading to signal modulation rate restriction (which is inversely proportional to the quality factor). On the other hand, the quality factor must be high enough to provide the entire frequency band separation into a row of separate channels. Keeping in mind the existing drawbacks of multiplexed schemes, a number of scientific groups proposed schemes without multiplexing. In particular, in Reference [3], the scheme based on plasmonic waveguides was presented. The main shortcoming of the design presented in Reference [3] is the extreme technological realization difficulty required for fabricating parallel data transmission lines, which implies the same sequence of outputs on the driving integrated circuit chip and inputs on the receiving integrated circuit chip. In practice, this condition is not met and usually, a comprehensive multilayer wiring (more than ten physical layers) is needed to ensure a layout of transmission lines without any intersections. The concept of interconnects without multiplexing was further developed in the European research project NAVOLCHI (Nanoscale Disruptive Silicon-Plasmonic Platform for Chip-to-Chip Interconnection) (Figure 1a) [7; 8; 9]. It was devoted to the development of a nanoscale plasmonic chip-to-chip and system-in-package interconnection platform, including integrated nanoscale light sources and photodetectors. The goal was to combine nanolasers with an operating wavelength of 1550 nm [10] and plasmonic modulators [8; 9] with silicon and polymer optical waveguides. In this project, signals from each nanolaser are transmitted using an individual waveguide to an individual photodetector. However, the technology of on-chip nanolasers [10; 11; 12] is insufficiently developed, therefore, their practical implementation is complicated. Taking into account the drawbacks of multiplexed schemes, we consider in this paper the scheme without multiplexing.