EP0352002A2
Expired / Lapsed
EP
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Optical nonreciprocal device
Assignee: HP Inc
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Filing: 1989-07-10
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Granted: —
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Expires: 2009-07-10
Abstract
Abstract An optical nonreciprocal device (10) comprises three anisotropic crystal members (12, 16, 20), each having a walk off direction for separating light into ordinary and extraordinary rays, and at least one non-reversible rotation element (14,18) interposed between every two adjacent anisotropic crystal members. The rotations of the elements (14, 18) and the orientations and thicknesses of the anisotropic crystal members (12, 16, 20) are such that light in the forward direction is separated into ordinary and extraordinary rays which are synthesized after passing through the device, whereas light in the reverse diretion is separated into ordinary and extraordinary rays which substantially do not superpose each other upon emerging from the device, independently of temperature and wavelength.
Inventors
- 👤 Kok Wai Chang
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 14:51
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/27; G02B6/2746; G02F; G02F1/00; G02F1/01; G02F1/09; G02F1/093; G02F2203/00; G02F2203/04; G02F2203/06; Y; Y10; Y10S; Y10S372/00; Y10S372/703
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
195 words
An optical nonreciprocal device (10; 100; 150; 200; 300) for passing light in a forward direction from a first point (1) to a second point (2) and for reducing light passing in a reverse direction from the second point to the first point, characterised in that it comprises: at least three anisotropic crystal members (12, 16, 20) arranged in a linear array, each member having a walk off direction for separating light into ordinary and extraordinary rays; and at least two non-reversible rotation elements (14, 18), wherein at least one of the elements is interposed between every two adjacent anisotropic crystal members, and wherein rotations of the elements and the orientations and thicknesses of the members are such that light in the forward direction is separated into ordinary and extraordinary rays which are synthesized when they arrive at the second point, and that light in the reverse direction is separated into ordinary and extraordinary rays which substantially do not superpose each other at the first point, and so that light passing in the reverse direction is reduced in a manner which is substantially insensitive to temperature and wavelengths of the light passing in either direction.
Claim 2
Dependent Claim
195 words
An optical nonreciprocal device (10; 100; 150; 200; 300) for passing light in a forward direction from a first point (1) to a second point (2) and for reducing light passing in a reverse direction from the second point to the first point, characterised in that it comprises: at least three anisotropic crystal members (12, 16, 20) arranged in a linear array, each member having a walk off direction for separating light into ordinary and extraordinary rays; and at least two non-reversible rotation elements (14, 18), wherein at least one of the elements is interposed between every two adjacent anisotropic crystal members, and wherein rotations of the elements and the orientations and thicknesses of the members are such that light in the forward direction is separated into ordinary and extraordinary rays which are synthesized when they arrive at the second point, and that light in the reverse direction is separated into ordinary and extraordinary rays which substantially do not superpose each other at the first point, and so that light passing in the reverse direction is reduced in a manner which is substantially insensitive to temperature and wavelengths of the light passing in either direction.
Claim 3
Dependent Claim
101 words
The device of claim 1, wherein each rotation element (14, 18) rotates the ordinary and extraordinary rays by about 45 degrees at predetermined light wavelengths, and wherein the rotations are affected by temperature and wavelengths of the rays so that the rotations performed by each element will deviate by an error angle from 45 degrees, so that the coupling loss of the device is proportional to the product of the squares of the cosine of the error angles, and so that the isolation of the device is proportional to the product of the squares of the sine of the error angles.
Claim 4
Dependent Claim
62 words
The device of claim 2, wherein a first rotation element (14) rotates rays of light at a first wavelength by about 45 degrees, and a second element (18) rotates rays of light at a second wave length by about 45 degrees, so that the device is effective for reducing light transmission in the reverse direction at both the first and second wavelengths.
Claim 5
Independent Claim
23 words
The device of any preceding claim, said device comprising three anisotropic crystal members (12, 16, 20) and two non-reversible rotation elements (14, 18).
Claim 6
Dependent Claim
95 words
The device of claim 4, wherein the array comprises a first member (12) closest to the first point, a second member (10) in the middle and a third member (20) closest to the second point, wherein the first and third members have substantially the same thickness and the thickness of the second member has a thickness which is substantially 1.41 times the thickness of the other two members, and wherein the walk off directions of the second and third members are orientated about 135 and 270 degrees respectively relative to that of the first member.
Claim 7
Independent Claim
29 words
The device of any of claims 1 to 3, said device (100 comprising four anisotropic crystal members (102, 106, 110, 114) and three non-reversible rotation elements (104, 108, 112).
Claim 8
Dependent Claim
101 words
The device of claim 6, wherein the array comprises a first member (102) closest to the first point, a fourth member (114) closest to the second point, a second member (106) adjacent to the first member and a third member (110) between the second and fourth members, wherein the first and third members have substantially the same thickness a and the second and fourth members have substantially the same thickness a/1.41, and wherein the second, third and fourth members are oriented so that their walk off direction are respectively 135, 270 and 135 degrees relative to that of the first member.
Claim 9
Dependent Claim
100 words
The device of claim 6 or 7 wherein a first rotation element (104) rotates rays of light at a first wavelength by about 45 degrees, and a second element (108) rotates rays of light by about 45 degrees, and the third element (112) rotates rays of light by about 45 degrees where such rays of light have a wavelength which is approximately the arithmetic mean of the first and second wavelengths so that the device is effective for reducing light transmission in the reverse direction at both the first and second wavelengths and at wavelengths between the first second wavelengths.
Claim 10
Dependent Claim
84 words
The device of claim 6, wherein the array comprises a first member closest to the first point, a fourth member closest to the second point, a second member adjacent to the first member and a third between the second and fourth members, wherein the first and third members have substantially the same thickness 1.41a, and wherein the second, third and fourth members are oriented so that their walk off directions are respectively 135, 180 and 225 degrees relative to that of the first member.
Claim 11
Dependent Claim
27 words
The device of claim 1, said device (150) comprising five anisotropic crystal members (152, 156, 160, 164, 168) and four non-reversible rotation elements (154, 158, 162, 166).
Claim 12
Dependent Claim
98 words
The device of claim 10, wherein a first rotation element rotates rays of light at a first wavelength by about 45 degrees, a second element rotates rays of light at a second wavelength by about 45 degrees, a third and a fourth element rotates rays of light each by 45 degrees at a third and a fourth wavelength, wherein the third and fourth wavelengths are between the first and second wavelengths so that the device is effective for reducing light transmission in the reverse direction at both the first and second wavelengths between the first and second wavelengths.
Claim 13
Dependent Claim
32 words
The device of claim 11, wherein the first wavelength is about 1.3 microns, the second wavelength is about 1.55 microns, and the third and fourth wavelengths are 1.37 and 1.44 microns respectively.
Claim 14
Independent Claim
92 words
The device of any of claims 10 to 12, wherein the array comprises a first, second, third, fourth and fifth member arranged in such order with the first member (152) closest to the first point and the fifth members (152, 160) have thickness a, the second and fourth members (156) and 164) thickness 1.41a, and the fifth member thickness 2a, and wherein the second, third, fourth and fifth members are orientated so that their walk off directions are respectively 135, 180, 315 and 90 degrees relative to that of the first member.
Claim 15
Independent Claim
51 words
The device of any preceding claim, further comprising: means (201) for supplying light of unknown polaritization from the first point in the forward direction towards to the second point; and means (215, 216) disposed adjacent to the first point for detecting the ordinary and extraordinary rays travelling in the reverse direction.
Claim 16
Independent Claim
82 words
The device of any of claims 1 to 13, further comprising: means (302) disposed adjacent to the second point for transmitting light of a predetermined polarization towards the first point, said transmitting means being so located relative to the second point that such light arrives at substantially the first point; and means (330) disposed substantially at the second point for detecting a beam formed by the synthesis of ordinary and extraordinary rays travelling from the first point to substantially the second point.
Claim 17
Dependent Claim
17 words
The device of claim 14 or 15, wherein the detecting means comprises one or more optical fibers.
References Cited (Backward Citations)
No citation records indexed.
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