Wavelength selective optical cross switch and optical add/drop multiplexer using volume phase grating and array of micro electro mechanical mirrors

US 6,671,428 Term ended

Overview Sources & methods

Term ended Jan 26, 2022 · From the USPTO record

Computed 20-year base term

Named at grant BaySpec, Inc. · find this owner

Filed Mar 20, 2001 as application 09/813,772 · Granted Dec 30, 2003

Base term plus 312 days of patent term adjustment (USPTO delay)

Today

20 years from filing

Term ended Jan 26, 2022

2001 2026

Clock starts
Mar 20, 2001

Term ended
Jan 26, 2022

Granted
Dec 30, 2003

base term patent term adjustment after the term ends fee events Updated Nov 15, 2026 · includes USPTO assignment & status data published Nov 15, 2026 and grant & fee data published Nov 10, 2026 (weekly) · how we know

312

Days of term adjustment

Read from the USPTO patent term adjustment record, not recalculated here.

None

Terminal disclaimer

No disclaimer on this record.

3 of 3

Maintenance fees paid

Three maintenance fees fall due, at 3.5, 7.5 and 11.5 years from grant. This counts the ones the record shows paid.

How we calculated this date

One row per rule, each showing its own input and what it did to the date. A step we could not verify says so instead of resolving itself.

Step	Input	Date after this step	Confidence
Base term, 20 years from filing	Clock starts Mar 20, 2001, when this application, 09/813,772, was filed	Mar 20, 2021	High confidence
Continuity chain	Every parent in the chain resolved	no change	High confidence
Patent term adjustment	+312 days, USPTO patent term adjustment record	Jan 26, 2022	High confidence
Terminal disclaimer cap	None on record	no cap applied	High confidence
Patent term extension	None on file	no change	High confidence
Fee events	3 of 3 maintenance fees paid	term ended	High confidence
Computed term end	The steps above, in order	Jan 26, 2022	From the USPTO record

Sources

Google Patents · The patent document at USPTO · Assignment records at USPTO

USPTO account required: This application in Patent Center · USPTO's maintenance fee lookup

Maintenance fee events come from USPTO's own fee records. Its fee lookup asks for the patent number and the application number.

Not on this page: the patent's family, its recorded assignments and its citation count. USPTO's assignment records, linked above, list every recorded assignment.

Every date shows its work: the base term, any term adjustment or extension, any disclaimer cap, and the maintenance fee record, each with a confidence tier. How this record was built

Computed patent terms end on the dates shown. Related patents and pending applications may cover overlapping subject matter.

Wavelength selective optical cross switch and optical add/drop multiplexer using volume phase grating and array of micro electro mechanical mirrors

Term ended Jan 26, 2022 · From the USPTO record

20-year base term ended Mar 20, 2021

How we calculated this date

Sources