# Shanghai Institute of Optics and Fine Mechanics (SIOM/CAS)
*research-institute . companies*

Chinese Academy of Sciences institute; developer of the ACDL laser subsystem for the DQ-1/DQ-2 missions.

## Specifications
- **country**: China
- **operator domains**: ["siom.ac.cn"]
- **entity type**: company
- **last verified date**: 2026-06-10
- **verified by**: agency-doc
- **claim status**: unclaimed
- **attributes**: {"kind":"research-institute","country":"China","operator_domains":"[\"siom.ac.cn\"]","description":"Chinese Academy of Sciences institute; developer of the ACDL laser subsystem for the DQ-1/DQ-2 missions."}

## Editorial
The Shanghai Institute of Optics and Fine Mechanics (SIOM) is a research institute of the Chinese Academy of Sciences (CAS), established in 1964 and located in the Jiading district of Shanghai. SIOM has conducted spaceborne laser and lidar development since 2001.[^siom-official-2026]

SIOM developed the Atmospheric Carbon dioxide Detector (ACDL), the principal science instrument on the Daqi-1 (DQ-1) and Daqi-2 (DQ-2) atmospheric monitoring satellites. The ACDL combines a high-spectral-resolution lidar (HSRL) at 532 nm with dual-polarization detection and an iodine vapour filter, together with an integrated path differential absorption (IPDA) channel at 1572 nm for column CO2 retrieval.[^amt-acdl-2024] DQ-1 launched in April 2022 and DQ-2 in April 2026.[^eoportal-daqi-siom-2026] The satellite buses for both missions were built by the Shanghai Academy of Spaceflight Technology (SAST).

The ACDL is a spaceborne HSRL-IPDA combined instrument for simultaneous aerosol and greenhouse gas profiling from a single platform.

## Sources
- [siom-official-2026] | Shanghai Institute of Optics and Fine Mechanics - Official Site | http://english.siom.cas.cn/ | tier=operator-marketing | accessed=2026-06-10
  Established 1964, CAS institute, Jiading Shanghai, space-borne laser/lidar development since 2001
- [amt-acdl-2024] | Aerosol optical property measurement using ACDL on DQ-1 | AMT 2024 | https://amt.copernicus.org/articles/17/4425/2024/ | tier=peer-reviewed | accessed=2026-06-10
  Peer-reviewed: SIOM developed ACDL for DQ-1; HSRL 532nm dual-polarization + iodine vapor filter + IPDA 1572nm for CO2
- [eoportal-daqi-siom-2026] | Daqi-1/-2 - eoPortal | https://www.eoportal.org/satellite-missions/daqi-1-2 | tier=agency-doc | accessed=2026-06-10
  Confirms SIOM as ACDL developer; DQ-1 launched 2022-04-15; DQ-2 launched 2026-04-17

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