Abstract: The disclosed technology generally relates to medical devices, and more particularly to a chemical fluid injection device. In an aspect, a chemical fluid injection device is configured to recognize whether a needle attached to a needle holder is inserted into a patient by sliding the needle holder and sensing whether the needle holder is adjacent to a needle penetration hole.

Abstract: A WDM optical transmission system with a bi-directional WDM-ADM is disclosed. The system includes first and second transceivers for multiplexing a multi-channel optical signal before transmission and for de-multiplexing a received multi-channel optical signal; and, a bi-directional WDM-ADM for interleaving the channels of an optical signal received from the first transceiver and the channels of an optical signal received from a second transceiver, for adding/dropping the interleaved optical signals according to channels, for de-interleaving the added/dropped optical signals into a first optical signal and a second optical signal, and for providing the first and the second optical signals to the first and second transceivers, respectively.