  Integrated superconducting spectrometer (ISS) technology will enable
ultra-wideband, integral-field spectroscopy for (sub)millimeter-wave astronomy,
in particular, for uncovering the dust-obscured cosmic star formation and
galaxy evolution over cosmic time. Here we present the development of DESHIMA
2.0, an ISS for ultra-wideband spectroscopy toward high-redshift galaxies.
DESHIMA 2.0 is designed to observe the 220-440 GHz band in a single shot,
corresponding to a redshift range of $z$=3.3-7.6 for the ionized carbon
emission ([C II] 158 $\mu$m). The first-light experiment of DESHIMA 1.0, using
the 332-377 GHz band, has shown an excellent agreement among the on-sky
measurements, the lab measurements, and the design. As a successor to DESHIMA
1.0, we plan the commissioning and the scientific observation campaign of
DESHIMA 2.0 on the ASTE 10-m telescope in 2023. Ongoing upgrades for the full
octave-bandwidth system include the wideband 347-channel chip design and the
wideband quasi-optical system. For efficient measurements, we also develop the
observation strategy using the mechanical fast sky-position chopper and the
sky-noise removal technique based on a novel data-scientific approach. In the
paper, we show the recent status of the upgrades and the plans for the
scientific observation campaign.
