I also tried:
add_field => [ "[geo_link][type]", "linestring" ]
add_field => [ "[geo_link][coordinates][0][0]", " -87.623177" ]
add_field => [ "[geo_link][coordinates][0][1]", "41.881832" ]
add_field => [ "[geo_link][coordinates][1][0]", " -87.623177" ]
add_field => [ "[geo_link][coordinates][1][1]", "41.881832" ]
but the same result.