US5054875A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fiber-optic equalizer
Assignee: Tacan Corp
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Filing: 1990-08-01
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Granted: 1991-10-08
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Expires: 2010-08-01
Abstract
Abstract A multi-mode optical fiber segment having partially reflecting mirrors on each end functions as a resonant cavity with respect to the modulation frequency when the length of the fiber is equal to one-half the modulation wavelength of the light injected into the fiber. Modulated light is injected through a hole in the mirror at one end, either from a fiber, a waveguide, or directly from a laser diode. The core diameter of the cavity fiber is limited only by the requirement that it must be much larger than the input hole. Light exits though a hole in the mirror opposite the input hole. Upon entry into the resonant cavity, light is subject to multi-modal propagation resulting in dispersion. The resultant output light of the fiber is lower overall in intensity, but its useful frequency response is expanded by the bandpass half-skirt of the fiber-optic filter.
Inventors
- 👤 Mark E. Curran
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 12:10
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/28; G02B6/293; G02B6/29346; G02B6/29358; H; H04; H04B; H04B10/00; H04B10/25; H04B10/2581
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
118 words
A method of extending the useful flat frequency response and increasing optical power of an optical device carrying an optical transmission of radio frequency signals which comprises: selecting a multi-mode optical fiber segment with a length equal to one-half the wavelength of a predetermined frequency; forming a pair of mirrors, one mirror on each end of said fiber segment so that a resonant cavity is formed to resonate light at said predetermined frequency; directing light into said fiber segment through a first mirror; and emitting light out of said fiber segment through a second mirror so that the emitted light has an extended useful flat frequency response and increased optical power beyond that of a non-equalized optical device.
Claim 2
Independent Claim
118 words
A method of extending the useful flat frequency response and increasing optical power of an optical device carrying an optical transmission of radio frequency signals which comprises: selecting a multi-mode optical fiber segment with a length equal to one-half the wavelength of a predetermined frequency; forming a pair of mirrors, one mirror on each end of said fiber segment so that a resonant cavity is formed to resonate light at said predetermined frequency; directing light into said fiber segment through a first mirror; and emitting light out of said fiber segment through a second mirror so that the emitted light has an extended useful flat frequency response and increased optical power beyond that of a non-equalized optical device.
Claim 3
Dependent Claim
25 words
A method as in claim 1 wherein the step of forming a pair of mirrors includes depositing a dielectric material on the respective fiber ends.
Claim 4
Dependent Claim
28 words
A method as in claim 1 wherein the step of directing light into said fiber segment comprises injecting light through a first axial hole in said first mirror.
Claim 5
Dependent Claim
28 words
A method as in claim 1 wherein the step of emitting light from said fiber segment comprises emitting light through a second axial hole in said second mirror.
Claim 6
Dependent Claim
57 words
A method as in claim 1 wherein the step of selecting a multi-mode optical fiber segment includes selecting a length such that the relationship L=λ/2=c/2nf c is satisfied, where λ is the modulation wavelength, c is the speed of light, n is the refractive index of said fiber segment and f c is the desired center frequency.
Claim 7
Independent Claim
222 words
A method of optical transmission of radio frequency signals with extended useful flat frequency response and increased optical power which comprises: selecting a multi-mode optical fiber segment with a length equal to one-half the wavelength of a predetermined frequency; forming a pair of mirrors, one mirror on each end of said fiber segment so that a resonant cavity is formed to resonate light at said predetermined frequency; directing a radio frequency signal into an RF splitter to provide a plurality of radio frequency signals; modulating the output light of each of a plurality of optical sources at the frequency of said radio frequency signal, each optical source of said plurality having a different wavelength; feeding the modulated output light into a wavelength division multiplexer to produce a single wavelength division multiplexed optical output; directing the multiplexed optical output into said fiber segment through a first mirror; emitting light out of said fiber segment through a second mirror so that the emitted light has an extended useful flat frequency response beyond that of a non-equalized optical device; transmitting output light into a wavelength division demultiplexer to separate light according to wavelength; receiving light of each wavelength at a separate receiver corresponding to each wavelength to produce an output radio frequency signal; and combining each output radio frequency signal into a single output signal.
Claim 8
Independent Claim
222 words
A method of optical transmission of radio frequency signals with extended useful flat frequency response and increased optical power which comprises: selecting a multi-mode optical fiber segment with a length equal to one-half the wavelength of a predetermined frequency; forming a pair of mirrors, one mirror on each end of said fiber segment so that a resonant cavity is formed to resonate light at said predetermined frequency; directing a radio frequency signal into an RF splitter to provide a plurality of radio frequency signals; modulating the output light of each of a plurality of optical sources at the frequency of said radio frequency signal, each optical source of said plurality having a different wavelength; feeding the modulated output light into a wavelength division multiplexer to produce a single wavelength division multiplexed optical output; directing the multiplexed optical output into said fiber segment through a first mirror; emitting light out of said fiber segment through a second mirror so that the emitted light has an extended useful flat frequency response beyond that of a non-equalized optical device; transmitting output light into a wavelength division demultiplexer to separate light according to wavelength; receiving light of each wavelength at a separate receiver corresponding to each wavelength to produce an output radio frequency signal; and combining each output radio frequency signal into a single output signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1994-10-07 | 1995-04-08 | 1995-10-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-10-07 | 1999-04-08 | 1999-10-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-10-07 | 2003-04-08 | 2003-10-08 | $7700.00 | Window Closed / Lapsed |