Menlo OFC Setup¶

This driver is split into one core device and several modules attached to it.

OFC opens the single QWebChannel websocket connection to the comb and exposes its raw control/status tree via get_node/set_node/explore.

Each functional-layer module (DDS, LaserLock, DualLaserLock, FXE, RepetitionRate, CEO, Oscillator) is a separate HERO. It takes the already-running OFC HERO as a constructor argument via BOSS’s "ofc": "$device_menlo_ofc" reference, so all modules share the one physical connection instead of each opening their own.

See examples/menlo/ofc.json for a complete BOSS config wiring one comb with all its modules.

Some CW channels lock two wavelengths through one shared lock loop, with two separate frequency-distribution blocks instead of one. Deploying plain LaserLock against one of these fails, since it hardcodes a single frequency-distribution node name that these channels don’t have. Use DualLaserLock instead, passing both wavelengths’ node names explicitly; see examples/menlo/ofc.json for an example.

FXE wraps the comb’s 16-channel frequency counter. Unlike the other modules, it has no default observables, since which channel carries which signal is deployment-specific. Pass observables for the channels relevant to your comb, e.g. a beat on channel 3:

"arguments": {
  "ofc": "$device_ofc",
  "observables": {
    "cw_beat": {"path": "counterFrequencies.channel03", "unit": "Hz"}
  }
}

Node paths (used in get_node/set_node/observables) are firmware-dependent and not documented by Menlo. Use format_tree() to find them interactively:

>>> print(ofc.format_tree("functionalLayer.rrSettings", depth=2))
functionalLayer.rrSettings
|-- dds
|   |-- ddsFrequency = 28286800
|   |-- outputOn = True
|   `-- outputPower = 0.64
|-- mainControls
|   |-- fastOutput ...
|   |-- lock = True
|   `-- slowOutput ...
`-- repetitionRate
    |-- rrCounterRepRate = 250105340.0
    `-- rrTargetBeatRF = 250105340

Nodes shown as ... are unexpanded branches; raise depth or call format_tree again rooted at that path to descend further. explore() returns the same tree as a plain dict instead of a rendered string, if you want to process it programmatically.

For anything specific to your comb (e.g. a customer-specific fiber-noise-cancellation module), poll or control it directly instead of adding a new class: every module accepts an observables argument, merged on top of its DEFAULT_OBSERVABLES, and OFC.get_node/OFC.set_node give full read/write access to any node regardless.

"arguments": {
  "host": "IP_OR_HOSTNAME",
  "observables": {
    "fnc578_locked": {"path": "functionalLayer.fnc578Settings.mainControls.lock", "unit": ""},
    "fnc1157_locked": {"path": "functionalLayer.fnc1157Settings.mainControls.lock", "unit": ""}
  }
}

Important

The OFC device’s _ensure_connected method must be reachable from the other modules over the network. HEROS excludes underscore-prefixed methods from a RemoteHERO proxy unless marked force_remote, so the OFC row in your BOSS config needs:

"extra_decorators": [["_ensure_connected", "heros.inspect.force_remote"]]

See examples/menlo/ofc.json for this in context.

Warning

The PyPI package named pywebchannel is an unrelated project; installing it will not work. Install it from source instead:

pip install "pywebchannel @ git+https://github.com/MenloSystems/pywebchannel"

pywebchannel is not declared as a project dependency, so this install step must be run manually wherever the Menlo driver is used: locally, in CI, and in any Docker image.

In a Docker Container deployment via BOSS, use the BOSS_PIP_PKGS environment variable (see the BOSS documentation) instead of extending the image:

docker-compose.yml¶

 services:
   device_ofc:
     image: registry.gitlab.com/atomiq-project/herosdevices:latest
     restart: always
     network_mode: host
     volumes:
       - ./ofc.json:/ofc.json:ro
     environment:
       - BOSS_PIP_PKGS=pywebchannel@git+https://github.com/MenloSystems/pywebchannel
     command: python -m boss.starter -u file:///ofc.json --log info