Silicon nitride polarization beam splitter based on polarization-independent MMIs and apodized Bragg gratings

Abstract

We present the design and experimental results of a novel polarization beam splitter (PBS) with a high polarization extinction ratio (PER) made on a Si3N4 platform. The PBS is composed of two identical polarization-independent multi-mode interferometers and two identical apodized Bragg gratings. The operating principle of this device is based on the fact that the TE and TM stopbands of the grating are centered at different wavelengths. The reflected and transmitted light from the gratings are routed to separate output ports by the two-MMI configuration. The experimental results show that a PER of > 30 dB is achieved over a bandwidth of 22 nm, with an insertion loss of ∼ 1.1 dB. The total length of the device is ∼ 820 µm.

Methods and applications of on-chip beam splitting: A review

“…According to the general design principle, it can realize multi inputs and multi outputs distribution. In recent years, for different separation characteristics, a number of improved designs for multimode waveguides have emerged, which can efficiently realize the functions of power beam splitting [60][61][62][63][64][65][66][67], polarization beam splitting [52][53][54][55][56][57][58][59], wavelength division multiplexing (WDM) [110][111][112][113][114], mode division multiplexing (MDM) [68,115,116], and the power splitter based on MMI coupling is easy to realize polarization-insensitive design. By analyzing the propagation of the photons, it is known that the position of the reproduced n-double image is: Where L π is the beat length, which is defined as:…”

“…Nowadays, several classical structures used for on-chip beam splitting mainly include y-branch waveguide [35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51], splitters based on multimode interference (MMI) coupling [52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69], splitters based on directional coupling (DC) [70][71][72][73][74][75], and splitters based on inverse design [76][77][78][79][80][81]. Among them, the design principle of y-branch waveguide is relatively simple, and the separation of mode and power is mainly realized through the y-type structure design.…”

Silicon and silicon nitride based bilayer polarization-insensitive optical filter

“…Silicon photonics provides a powerful platform for wavelength division multiplexing (WDM) technology because of the CMOS compatibility and high integration density. Meanwhile, silicon nitride materials [1][2][3][4][5] have attracted the interest of many researchers because of their small refractive index difference and temperature insensitivity. An ideal WDM filter requires a flat-passband and broad bandwidth.…”

Nano-wire bridge waveguide-assisted silicon polarizing beam splitter

“…However, its high index contrast also leads to strong birefringence, further causing the polarization sensitive properties. Thus, polarizing beam splitter (PBS) is usually essential for silicon-based photonic integrated circuits [9], which can separate the orthogonally polarized transverse electric (TE) and transverse magnetic (TM) modes into different pathways [10][11][12][13][14][15][16].…”