\input{preamble.tex}
\graphicspath{{images}, {images/1550}}

\title{1550 Laser Diode Driver Kirdy}
\author{M-Labs Limited}
\date{January 2025}
\revision{Revision 1}
\companylogo{\includegraphics[height=0.73in]{artiq_sinara.pdf}}

\begin{document}
\maketitle

\section{Features}

    \begin{itemize}
        \item{300mA max output current, 20-bit resolution}
        \item{Low noise current source}
        \item{18MHz-bandwidth modulation input}
        \item{Monitor photodiode and LD protection}
        \item{Built-in sub-mK stability temperature controller}
        \item{Full digital control over Ethernet}
    \end{itemize}

\section{Applications}

    \begin{itemize}
        \item{High-precision laser driver}
        \item{Suitable for use with adapter and preinstalled laser assembly or with external laser heads}
        \item{Spectroscopy and oher atomic physics applications}
    \end{itemize}

\section{General Description}

The 1550 Laser Diode Driver Kirdy is a 8hp EEM form factor module, part of the Sinara open hardware family. It serves as a precision laser diode driver, featuring a low-noise current source, low- and high-frequency modulation inputs, and full digital control over Ethernet. Soft turn-on, laser power monitoring with a user-defined trip point, overtemperature protection, and a protection relay minimize the risk of damage to the laser diode. 

1550 Kirdy supports both low-frequency modulation, suitable for laser locks and linewidth reduction, as well as RF modulation injected directly into the diode, typically to inject sidebands into the beam and implement stabilization schemes such as Pound-Drever-Hall and modulation transfer spectroscopy. 

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\begin{figure}[hbt!]
    \centering
    \includegraphics[height=2.5in]{photo1550.jpg}
    \caption{Kirdy card photo}
    \includegraphics[height=3in, angle=90]{fp1550.pdf}
    \caption{Kirdy front panel}
\end{figure}

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\sourcesection{1550 Laser Diode Driver Kirdy}{https://git.m-labs.hk/sinara-hw/kirdy} The associated adapter can be found at the repository /url{https://git.m-labs.hk/sinara-hw/kirdyAdapter/src/branch/master}. 

\section{Adapter and Laser Options}

An optional adapter allows compact lasers in butterfly packages to be mounted directly onto 1550 Kirdy, with a fibre-optic output in the front panel. Multiple single-frequency narrow-linewidth lasers are currently available as preinstalled options for order.

Alternatively, Kirdy accepts laser signals broken out to the front panel and is suitable for use in driving external laser heads, including commercial or custom ECDLs (with additional piezo driver) or injection-locked Fabry-Perot diodes.

\section{Specifications}

microcontroller datasheet: \url{https://www.st.com/resource/en/datasheet/DM00037051.pdf}

1550 Kirdy supports Power-over-Ethernet. Alternatively, power can be provided via 12V DC input in front panel. 

300mA max output
4V compliance

20 bit DAC control, 50Hz bandwidth
300pA/rt Hz current noise @ 1kHz
300nA RMS Noise (10Hz - 1MHz)

Laser power monitor

    0 - 2.5mA Photodiode current monitoring

TEC Controller

    1A max output
    5V compliance
    +- 1mK stability

\section{Selecting modulation gain}

DC to 10MHz modulation input (+/- 1V max) with selectable modulation gains
    0.25mA/V
    2.5mA/V
    25mA/V

\section{Firmware and Linien}

1550 Kirdy features front panel Ethernet and USB-C. Either DFU or OpenOCD can be used to flash firmware; OpenOCD however requires a JTAG adapter.

It can be connected in particular to the Sinara Fast-Servo and used with the Linien application that enables easy locking of lasers to spectral lines.

https://github.com/linien-org/linien

https://git.m-labs.hk/M-Labs/nix-servo

\ordersection{1550 Laser Diode Driver Kirdy}. 

\finalfootnote

\end{document}
