Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Efficient and mode selective spatial mode multiplexer based on
  Multi-Plane Light Conversion   We designed and built a new type of spatial mode multiplexer, based on
Multi-Plane Light Conversion (MPLC), with very low intrinsic loss and high mode
selectivity. In this first demonstration we show that a typical 3-mode
multiplexer achieves a mode selectivity better than -23 dB and a total
insertion efficiency of -4.1 dB (optical coating improvements could increase
efficiency to -2.4 dB), across the full C-band. Moreover this multiplexer is
able to perform any mode conversion, and we demonstrate its performance for the
first 6 eigenmodes of a few-mode fiber: LP$_{01}$, LP$_{11\mathrm{a}}$,
LP$_{11\mathrm{b}}$, LP$_{02}$, LP$_{21\mathrm{a}}$ and LP$_{21\mathrm{b}}$.

36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
16
The categories of this paper are: stat
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ
7
The categories of this paper are: hep-th
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph