Analysis of optical fiber-based LP_01 ↔ LP_02 mode converters for the O-, S-, and C-Band

Abstract

This paper proposes a double fiber taper-based mode converter that converts LP(01) to LP(02) and vice versa. The first taper is used to convert LP(01) to some higher order LP(0m) (m>1) modes while the second taper suppresses the undesired higher order modes (m>2) and results in LP(02) overwhelmingly dominated. A simulation shows that conversion efficiency of almost 100% at the central wavelength of O-, S-, and C-Band, and above 98% over the S- and C-Band was achieved. Moreover, suppression of undesired higher order modes is more than 10 dB over the whole O-, S-, and C-Band. In particular, the suppression is more than 19 dB for the whole C-Band. The analysis also shows that the performance of the mode converter is not sensitive to slight variations of the converter's parameters. The same converter also can be used to convert LP(02) back to LP(01). It is shown that conversion efficiency higher than 99% and suppression of undesired higher order modes higher than 30 dB can be obtained. Further, a (de)multiplexer for an LP(02) and an LP(01) mode was designed using the mode converter combined with a symmetric directional coupler. The multiplexer is broadband and has an insertion loss less than 0.5 dB in the C-Band.

Recent progress in optical devices for mode division multiplex transmission system

“…The conversion approach with minimum IL (0.2-0.5 dB) reported here is the mechanical mode converter [26], which employs periodic structure using the grating period (PSG). The all-fiber-doubly tapered converter demonstrates higher conversion efficiency (CE) close to 97-99% [27].…”

Iterative method for the design of LP0m mode converter

“…For an LP 0m mode converter, based on multimode interference, an all-fiber LP 02 mode converter was proposed with a broad optical bandwidth [5]. A double fiber taperbased mode converter was proposed to convert LP 01 to LP 02 with more than 98% efficiency [6].…”

Design optimisation of a waveguide‐based LP 01 –LP 0m mode converter by using artificial intelligence technique

“…The more structural parameters are included, the more difficult the design/optimisation process is, and also a larger degree of freedom can be achieved in design. Other researchers in this field, usually try to manipulate the structural parameters by some try and error simulations to find out the relations between the structural parameters and the device output merit factors [14]. Therefore, the process and human involvement are tedious, and also the final design will mostly be far from the optimal structure.…”