Menlo Dual Laser Lock¶
From: Menlo Systems
Class: herosdevices.hardware.menlo.dual_laser_lock.DualLaserLock
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:
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 a dual-wavelength laser-lock channel of a Menlo Systems frequency comb.
Some CW channels (e.g. “CW 507 / 1014 / 1542”, “CW 578 / 1157 / 1542” in Menlo’s vendor software) lock two
wavelengths through one shared dds/mainControls/frequencyControl/amp* node set, but have two
separate frequencyDistribution<wavelength> blocks (one per wavelength) instead of a single plain
frequencyDistribution, plus a single-wavelength thermo-electric-cooler node. Deploying plain
LaserLock against one of these channels fails, since its
frequencyDistribution.* properties hardcode a node name these channels don’t have - use DualLaserLock
instead, which composes both wavelength-suffixed nodes plus the TEC node explicitly.
Bold arguments are mandatory. For more information on the listed arguments refer to the class documentation: herosdevices.hardware.menlo.dual_laser_lock.DualLaserLock 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 dual-wavelength channel belongs to. |
|
funclayer_identifier |
<class ‘str’> |
Identifier of the module’s functional-layer settings object, e.g. “cw507_1014” for the sub-tree at functionalLayer.cw507_1014Settings. |
|
primary_frequency_distribution_node |
<class ‘str’> |
Relative node name of the first wavelength’s frequency-distribution block (mapped to |
|
secondary_frequency_distribution_node |
<class ‘str’> |
Relative node name of the second wavelength’s frequency-distribution block (mapped to |
|
tec_node |
<class ‘str’> |
Relative node name of the channel’s thermo-electric-cooler block, e.g. “spt1014Tec”. |
|
amp_node |
str | None |
None |
Relative node name of the channel’s shared laser-diode current-control block (amp*), see |
observables |
dict[str, dict[str, str]] | None |
None |
Additional observables to poll, merged on top of DEFAULT_OBSERVABLES, see |
The following JSON strings can be used to start a HERO device representation of DualLaserLock using BOSS.
{
"_id": "device_menlo_ofc_cw507_1014",
"classname": "herosdevices.hardware.menlo.DualLaserLock",
"arguments": {
"ofc": "$device_menlo_ofc",
"funclayer_identifier": "cw507_1014",
"primary_frequency_distribution_node": "frequencyDistribution507",
"secondary_frequency_distribution_node": "frequencyDistribution1014",
"tec_node": "spt1014Tec",
"amp_node": "amp507_1014"
},
"datasource": {
"async": false,
"interval": 15
}
}
Note
This example contains a variable that references another HERO with $.
from examples/menlo/ofc.json
{
"_id": "my_DualLaserLock",
"classname": "herosdevices.hardware.menlo.dual_laser_lock.DualLaserLock",
"arguments": {
"ofc": "<class 'herosdevices.hardware.menlo.ofc.OFC'>",
"funclayer_identifier": "<class 'str'>",
"primary_frequency_distribution_node": "<class 'str'>",
"secondary_frequency_distribution_node": "<class 'str'>",
"tec_node": "<class 'str'>",
"amp_node": null,
"observables": null
}
}
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