Menlo Oscillator

From: Menlo Systems

Class: herosdevices.hardware.menlo.oscillator.Oscillator

Driver Quality Index: alpha

Additional Information Check before use

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

Driver for the main seed oscillator (fs laser) of a Menlo Systems frequency comb.

Wraps the OFC’s functionalLayer.ofcSettings sub-tree, a fixed, singleton module (there is only one seed oscillator per OFC, so unlike DDS/ LaserLock there is no funclayer_identifier to select).

ofcSettings also has xps/fsOscillator pump-diode current-control nodes (e.g. xps.diode01, fsOscillator.preampDiode01), but which diodes are actually populated appears to vary by comb configuration (one observed unit had diode01/diode03/diode04 under both trees, with no diode02) - not modeled here since it isn’t confirmed to be a fixed, general shape. Poll/control specific diode nodes for your comb via observables, or ofc.get_node/set_node directly.

Bold arguments are mandatory. For more information on the listed arguments refer to the class documentation: herosdevices.hardware.menlo.oscillator.Oscillator If parameters appear in this list but not in the class definition, please recursively check the linked base classes for the definition of the parameter.

Argument

Type

Default Value

Description

ofc

<class ‘herosdevices.hardware.menlo.ofc.OFC’>

The OFC HERO this oscillator belongs to.

observables

dict[str, dict[str, str]] | None

None

Additional observables to poll, merged on top of DEFAULT_OBSERVABLES, see FunctionalLayerModule.

The following JSON strings can be used to start a HERO device representation of Oscillator using BOSS.

{
    "_id": "device_menlo_ofc_oscillator",
    "classname": "herosdevices.hardware.menlo.Oscillator",
    "arguments": {
        "ofc": "$device_menlo_ofc"
    },
    "datasource": {
        "async": false,
        "interval": 15
    }
}

Note

This example contains a variable that references another HERO with $.

from examples/menlo/ofc.json

{
    "_id": "my_Oscillator",
    "classname": "herosdevices.hardware.menlo.oscillator.Oscillator",
    "arguments": {
        "ofc": "<class 'herosdevices.hardware.menlo.ofc.OFC'>",
        "observables": null
    }
}

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