V-number

Code snippets

curl "https://api.oanor.com/fiber-api/v1/v-number" \
  -H "x-oanor-key: oanor_test_..."

await fetch("https://api.oanor.com/fiber-api/v1/v-number", {
  headers: { "x-oanor-key": "oanor_test_..." }
});

$ch = curl_init("https://api.oanor.com/fiber-api/v1/v-number");
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-oanor-key: oanor_test_..."]);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$out = curl_exec($ch);

import requests
requests.get(
    "https://api.oanor.com/fiber-api/v1/v-number",
    headers={"x-oanor-key": "oanor_test_..."}
)

Example response

A real response from this endpoint, captured by the latest health check.

{
    "data": {
        "note": "V = 2π·a·NA/λ (normalized frequency). A fibre is single-mode when V < 2.405; above the cutoff wavelength it supports only the fundamental mode.",
        "inputs": {
            "wavelength_m": 1.31e-6,
            "core_radius_m": 4.5e-6,
            "numerical_aperture": 0.2425
        },
        "v_number": 5.233989,
        "mode_regime": "multimode",
        "single_mode": false,
        "cutoff_wavelength_m": 2.850946e-6
    },
    "meta": {
        "timestamp": "2026-06-05T11:30:30.816Z",
        "request_id": "6b4fced6-933c-4f3c-b52a-ab25b79f5bd7"
    },
    "status": "ok",
    "message": "V-number",
    "success": true
}