Integrated photonic power divider with arbitrary power ratios

Abstract

Integrated optical power splitters are one of the fundamental building blocks in photonic integrated circuits. Conventional multimode interferometer-based power splitters are widely used as they have reasonable footprints and are easy to fabricate. However, it is challenging to realize arbitrary split ratios, especially for multi-outputs. In this Letter, an ultra-compact power splitter with a QR code-like nanostructure is designed by a nonlinear fast search method. The highly functional structure is composed of a number of freely designed square pixels with the size of 120×120 nm which could be either dielectric or air. The light waves are scattered by a number of etched squares with optimized locations, and the scattered waves superimpose at the outputs with the desired power ratio. We demonstrate 1×2 splitters with 1:1, 1:2, and 1:3 split ratios, and a 1×3 splitter with the ratio of 1:2:1. The footprint for all the devices is only 3.6×3.6 μm. Well-controlled split ratios are measured for all the cases. The measured transmission efficiencies of all the splitters are close to 80% over 30 nm wavelength range.

Subwavelength-Grating Metamaterial Structures for Silicon Photonic Devices

“…The most compact devices, with footprints of the order of 10 µm 2 have been achieved using "inverse design" approaches, with the local refractive index profile optimized in both the longitudinal and transversal direction to achieve a specific functionality [24], [25]. However, these devices still have a limited performance and smaller bandwidth compared to other solutions.…”

Silicon chip-scale space-division multiplexing: from devices to system

“…Also, the objective-first inverse-design algorithm is an efficient way, where an alternative binarization method is introduced to obtain a "binary" structure with two materials only [93]. It has been used in automated design of photonic devices having ultracompact footprint [94][95][96][97][98][99]. In addition, compact bend is also achieved for a photonic crystal waveguide with high transmission and suppressed inter-mode crosstalk [100].…”

A Numerical Solution for Broadband PLC Splitter with Variable Splitting Ratio Based on Asymmetric Three Waveguide Structures

“…Several power splitting technologies have been developed, such as adiabatic Y branches [3], directional couplers [4], and multimode interference (MMI) couplers [5]. Some special MMI couplers based on special design are proposed to realize the function of arbitrary power splitting ratio, such as surface relief holograms [6], angled structure [7], special butterfly geometrical structure [8], cascaded step-size structure [9], quick response (QR) code-like structure [10], and asymmetric interference structure [11]. Some of those techniques are wavelength sensitive and some are wavelength insensitive.…”

“…Some of those techniques are wavelength sensitive and some are wavelength insensitive. Some of those MMI components are sensitive to wavelength [6][7][8] while some are wavelength insensitive [9][10][11]. Arbitrary-ratio power splitters with wavelength insensitivity are appealing for…”

“…2019, 9, 1892 2 of 10 power splitter applications. In this study, 1 × 2 MMI power splitters with 1:1, 1:2, 1:3 split ratios by using QR code-like structure are demonstrated [10]. The measured transmission efficiencies of those splitters are near 80% within the range from 1530 to 1560 nm.…”