Alan W Donaldson

US Patent:

6771910, Aug 3, 2004

Filed:

Aug 25, 2000

Appl. No.:

09/648151

Inventors:

Bruce R Napier - Torquay, GB
Alan Donaldson - Clarksville MD

Assignee:

Nortel Networks Limited - St. Laurent

International Classification:

G02B 602

US Classification:

398185, 398 98

Abstract:

The capacity of an optical transmission system can in principle be increased by interleaving two bits streams with orthogonal polarisation states. This requires, in the interleaved bit stream, the bits of one component bit stream to be timed to occur close to midway between the bits of the other component bit stream. Achieving this by adjustment of relative optical path lengths upstream of the interleaver requires control of those lengths to Â200 microns for Â1 ps bit interleaving accuracy. Such precision is awkward to achieve using fusion splicing. Instead, the necessary precision of interleaving accuracy is achieved by trimming a length of birefringent fiber inserted downstream of the interleaving, this fiber oriented to have its principal polarisation planes (principal axes) aligned with the polarisation states of the two bit streams. Employing birefringent fiber with a beat length of 2. 5 mm makes adjustment of fiber length for Â1 ps bit interleaving accuracy very readily achievable, being of the order of Â500 mm.

US Patent:

6795620, Sep 21, 2004

Filed:

Nov 27, 2002

Appl. No.:

10/304699

Inventors:

Robert Tavlykaev - Ellicott City MD
Alan Donaldson - Clarksville MD

Assignee:

Codeon Corporation - Columbia MD

International Classification:

G02B 642

US Classification:

385 48

Abstract:

A method and optical tap is provided for forming a monitor signal that is a measure of optical power in a guided mode output of an optical modulator. The method and optical tap may monitor the guided mode power without tapping the guided mode light, even when optical power of the radiation modes is non-complementary to that of the output mode. Light from the radiation modes of the optical modulator is coupled into the wall of a capillary through a front face. Separate portions of the radiation mode light are reflected into photodetectors, which form photocurrents that are incoherently added to form the monitor signal.

US Patent:

7103257, Sep 5, 2006

Filed:

Feb 27, 2002

Appl. No.:

10/083464

Inventors:

Alan Donaldson - Clarksville MD, US
Yu Yan - Jessup MD, US

Assignee:

Codeon Corporation - Columbia MD

International Classification:

G02B 6/00

US Classification:

385138

Abstract:

A fiber tail assembly is provided that includes an outer sleeve, which can be attached and hermetically sealed to the housing of an optical device, and a sealing ferrule, which may be inserted into and hermetically sealed to the outer sleeve. An optical fiber may be inserted through an axial bore in the sealing ferrule and hermetically sealed thereto, such as with a glass seal. The hermetic seal between the sealing ferrule and the fiber avoids high or transversely asymmetric stress that may change the birefringence of the fiber. The optical fiber may be inserted through a cap ferrule or a stress relief tube, which may be attached to the fiber and to the outer sleeve, protecting the fiber tail assembly from axial stress that may damage the fiber or the hermetic seals. Methods for forming the same are provided.

US Patent:

20210242662, Aug 5, 2021

Filed:

Jan 29, 2021

Appl. No.:

17/162104

Inventors:

- Jessup MD, US
Alan DONALDSON - Clarksville MD, US
Jacob MERTZ - Elkridge MD, US
Robert ROCHE - Laurel MD, US

International Classification:

H01S 5/0687
H01S 5/00
H01S 5/02326
H01S 5/024
H01S 5/04
H01S 5/02216

Abstract:

A tunable laser assembly housed in a single enclosure and a method of control is described that provides high-speed monitoring and control of the spectral properties of widely tunable lasers, such as MEMS-tunable VCSELs, with an optical configuration that does not introduce perturbations into the swept-source laser output spectrum that would cause artifacts in imaging applications such as optical coherence tomography (OCT).