US5221839A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Double bevel gradient-index rod lens optical receiver having high optical return loss
Assignee: Agilent Technologies Inc
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Filing: 1991-02-15
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Granted: 1993-06-22
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Expires: 2011-02-15
Abstract
Abstract A gradient-index (GRIN) rod lens for use in an optical receiver, in which the end face of the GRIN rod lens opposite a photodetector is bevelled. The resulting optical receiver achieves an optical return loss which is >10 dB higher than known optical receivers having a bevelled end solely on an optical launch side of the GRIN rod lens.
Inventors
- 👤 David M. Braun
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 03:19
CPC Classifications
G; G02; G02B; G02B3/00; G02B3/0087; G02B13/00; G02B13/0095; G02B6/00; G02B6/24; G02B6/42; G02B6/4201; G02B6/4204; G02B6/4207; G02B6/26; G02B6/32; G02B6/327; G02B6/36; G02B6/38; G02B6/3807; G02B6/381; G02B6/3818; G02B6/3822
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
170 words
An optical receiver, comprising: an optical launch having an end face; a gradient-index (GRIN) rod lens, the GRIN rod lens comprising a rod lens oriented along an optical axis, the GRIN rod lens having an entrance face and an exit face, the entrance face of the GRIN rod lens being bevelled at a first predetermined angle with respect to the optical axis, and the exit face of the GRIN rod lens being bevelled at a second predetermined angle with respect to the optical axis; and a photodetector having a receiving surface, the photodetector being tilted at a third predetermined angle with respect to normal incidence; the optical launch, GRIN rod lens, and photodetector forming an optical circuit with the end face of the optical launch being opposite the entrance face of the GRIN rod lens and spaced apart therefrom by a first air gap and the exit face of the GRIN rod lens being opposite the receiving surface of the photodetector and spaced apart therefrom by a second air gap.
Claim 2
Dependent Claim
170 words
An optical receiver, comprising: an optical launch having an end face; a gradient-index (GRIN) rod lens, the GRIN rod lens comprising a rod lens oriented along an optical axis, the GRIN rod lens having an entrance face and an exit face, the entrance face of the GRIN rod lens being bevelled at a first predetermined angle with respect to the optical axis, and the exit face of the GRIN rod lens being bevelled at a second predetermined angle with respect to the optical axis; and a photodetector having a receiving surface, the photodetector being tilted at a third predetermined angle with respect to normal incidence; the optical launch, GRIN rod lens, and photodetector forming an optical circuit with the end face of the optical launch being opposite the entrance face of the GRIN rod lens and spaced apart therefrom by a first air gap and the exit face of the GRIN rod lens being opposite the receiving surface of the photodetector and spaced apart therefrom by a second air gap.
Claim 3
Dependent Claim
32 words
The optical receiver of claim 1 wherein the optical launch is an optical fiber having an end face which is bevelled at a fourth predetermined angle with respect to the optical axis.
Claim 4
Dependent Claim
15 words
The optical receiver of claim 2 wherein the optical fiber is a single mode fiber.
Claim 5
Dependent Claim
45 words
The optical receiver of claim 2 wherein the first predetermined angle and the fourth predetermined angle are such that with the GRIN rod lens and optical fiber geometric center axes parallel, a predetermined lateral offset provides an on-axis optical path through the GRIN rod lens.
Claim 6
Dependent Claim
19 words
The optical receiver of claim 2 wherein the second predetermined angle and the fourth predetermined angle are corresponding angles.
Claim 7
Dependent Claim
18 words
The system of claim 5 wherein the second predetermined angle and the fourth predetermined angle are approximately 10.5°.
Claim 8
Dependent Claim
20 words
The optical receiver of claim 2 wherein the GRIN rod lens is spaced equidistantly between the optical fiber and photodetector.
Claim 9
Dependent Claim
44 words
The optical receiver of claim 2 wherein the first predetermined angle is approximately 8°, the second predetermined angle and the fourth predetermined angle are approximately 10.5°, the third predetermined angle is approximately 22°, and the first and second air gaps are approximately 1.3 mm.
Claim 10
Dependent Claim
23 words
The optical receiver of claim 1 wherein the photodetector is a frontside illuminated In 0 .53 Ga 0 .47 As/InP p-i-n photodiode detector.
Claim 11
Dependent Claim
31 words
The optical receiver of claim 1 wherein the receiving surface is coated with an anti-reflection coating to reduce reflections at the interface of the second air gap and the receiving surface.
Claim 12
Dependent Claim
15 words
The optical receiver of claim 10 wherein the anti-reflection coating is a silicon nitride coating.
Claim 13
Dependent Claim
31 words
The optical receiver of claim 1 wherein the second air gap is adjustable so that the GRIN rod lens properly focuses light received from the optical launch onto the receiving surface.
Claim 14
Dependent Claim
24 words
The optical receiver of claim 1, further comprising an anti-reflection coating applied to the entrance face to reduce specular reflections and improve optical transmission.
Claim 15
Dependent Claim
15 words
The optical receiver of claim 13 wherein the anti-reflection coating is a silicon nitride coating.
Claim 16
Dependent Claim
34 words
The optical receiver of claim 1 wherein the second predetermined angle is such that reflection from the exit face of the GRIN rod lens is due only to diffuse reflection and not specular reflection.
Claim 17
Dependent Claim
35 words
The optical receiver of claim 1 wherein the GRIN rod lens is a microlens, type H, refractive index n 0 (λ=1300 nm)=1.636, n 0 (λ=1550 nm)=1.634, diameter 1.8 mm, and 0.27 pitch at λ=1300 nm.
Claim 18
Dependent Claim
19 words
The optical receiver of claim 1 wherein the first predetermined angle and the second predetermined angle are different angles.
Claim 19
Dependent Claim
22 words
The optical receiver of claim 17 wherein the first predetermined angle is approximately 8° and the second predetermined angle is approximately 10.5°.
References Cited (Backward Citations)
US4331380A
Cited
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1996-06-21 | 1996-12-21 | 1997-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-06-21 | 2000-12-21 | 2001-06-22 | $3760.00 | Window Closed / Lapsed |
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