A light polarizing beam splitter

Abstract

The invention discloses an optical polarization beam splitter. The beam splitter of the present invention includes a directional coupler whose narrow waveguide receives the input light source and TE 0 light output, and the TM that puts that input into the light source 0 Light is coupled into a wide waveguide and converted into a TM 1 light, the output end of the wide waveguide is connected with the first MMI coupler, and the first MMI coupler connects the input TM 1 The light is divided into two TM beams with equal power and 180° phase difference 0 Polarized light; its two output ends are respectively connected to the input end of the second MMI coupler through a 90° phase shifter, and an output end of the second MMI coupler is used as TM 0 Polarized light output port; length of first MMI coupler L π 1 is the beat length of the first MMI coupler; the second MMI coupler is an interference coupler. The invention can realize a high-capacity single-chip integrated chip, and has the characteristics of large bandwidth, very high extinction ratio and low loss.

Description

technical field [0001] The invention relates to the fields of optical communication, optical interconnection and optical device integration, specifically, an optical polarization beam splitter based on the combination of a directional coupler, a phase shifter and an MMI coupler. Background technique [0002] In future optical interconnection and optical communication chips, optoelectronic integrated circuits (PICs) with high capacity, compact size and low cost will become people's first choice. There are currently several ways to increase capacity, among which the multiplexing of polarization modes is an effective solution. Polarization beam splitter, as an important device to achieve polarization multiplexing, has also become a research hotspot. [0003] Current multi-mode interference beam splitters, polarization beam splitters, and polarization beam splitters using multi-mode interference principles and common multiple principles are all relatively large in size. Some r...

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Problems solved by technology

Some reports use the principle of quasi-imaging to reduce the size, but quasi-imaging has an additional loss of 2dB due to its own imaging characteristics, and the bandwidth is not very large

The reported traditional symmetric directional coupler usually utilizes L=pL πTE =qL πTM , among them, L πTE and L πTM is the coupling length of TE and TM modes, p and q are integers satisfying p=q+m (m=±1,3,5…), in order to satisfy the above formula, the size of the waveguide needs to be strictly controlled, and the size of the device Relatively long, especially for weakly confining index waveguide materials

Recently reported polarizing beam splitters based on symmetrical directional couplers are relatively compact in size, but the extinction ratio is not very high

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