US5796506A
Expired / Lapsed
US
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Submillimeter indirect heterodyne receiver and mixer element
Assignee: Individual
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Filing: 1995-11-21
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Granted: 1998-08-18
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Expires: 2015-11-21
Abstract
Abstract A coherent receiver for electromagnetic radiation comprising an input optics (10) for collecting an input signal of electromagnetic radiation at a frequency F S , an optical local oscillator (100) for generating an optical signal at a frequency F O amplitude-modulated at a frequency F LO , a mixer element (60) responsive simultaneously to the frequencies F S , F O , and F LO , where the input signal is injected electrically into the mixer element and the optical signal is injected optically into the mixer element to produce an output signal at a frequency F IF equal to the difference between F S and F LO , and electronics (50) connected to the mixer element for processing the output signal.
Inventors
- 👤 Charles Su-Chang Tsai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 19:47
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/60; H04B10/61; H04B10/64
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
149 words
A coherent receiver for electromagnetic radiation comprising: an input optics means for collecting an input signal of electromagnetic radiation at a frequency F S lower than approximately 10 13 Hz, an optical local oscillator means for generating an optical signal at a frequency F O higher than approximately 3×10 13 Hz, said optical signal is amplitude-modulated at a frequency F LO lower than approximately 10 13 Hz, a mixer element means responsive simultaneously to said frequencies F S , F O , and F LO , wherein said input signal is injected electrically into said mixer element means and said optical signal is injected optically into said mixer element means to produce an output signal at a frequency F IF substantially equal to the difference between said frequencies F S and F LO , and an electronics means connected to said mixer element means for processing said output signal.
Claim 2
Dependent Claim
149 words
A coherent receiver for electromagnetic radiation comprising: an input optics means for collecting an input signal of electromagnetic radiation at a frequency F S lower than approximately 10 13 Hz, an optical local oscillator means for generating an optical signal at a frequency F O higher than approximately 3×10 13 Hz, said optical signal is amplitude-modulated at a frequency F LO lower than approximately 10 13 Hz, a mixer element means responsive simultaneously to said frequencies F S , F O , and F LO , wherein said input signal is injected electrically into said mixer element means and said optical signal is injected optically into said mixer element means to produce an output signal at a frequency F IF substantially equal to the difference between said frequencies F S and F LO , and an electronics means connected to said mixer element means for processing said output signal.
Claim 3
Dependent Claim
43 words
A receiver according to claim 1, wherein said optical local oscillator means comprises two nearly-monochromatic light sources at two frequencies F 01 and F 02 separated in frequency by said frequency F LO and centered in frequency around said frequency F O .
Claim 4
Dependent Claim
31 words
A receiver according to claim 2, wherein said light sources at said frequencies F 01 and F 02 are stabilized by locking to two cavity modes of a reference optical resonant-cavity.
Claim 5
Dependent Claim
76 words
A receiver according to claim 1, wherein said mixer element means comprises: a metal contact, a mixing section of a thickness t and an average doping concentration d, said mixing section comprising semiconductor materials optically absorbing at said frequency F O , a Schottky barrier formed from said metal contact and said mixing section, and a contact section comprising semiconductor materials optically transparent at said frequency F O , said contact section adjoins said mixing section.
Claim 6
Dependent Claim
43 words
A receiver according to claim 4, wherein said optical local oscillator means comprises two nearly-monochromatic light sources at two frequencies F 01 and F 02 separated in frequency by said frequency F LO and centered in frequency around said frequency F O .
Claim 7
Dependent Claim
31 words
A receiver according to claim 5, wherein said light sources at said frequencies F 01 and F 02 are stabilized by locking to two cavity modes of a reference optical resonant-cavity.
Claim 8
Dependent Claim
74 words
A receiver according to claim 4, wherein said thickness t is smaller than ##EQU4## where v n is the maximum electron-drift velocity of said semiconductor materials in said mixing section, and said average doping concentration d is higher than ##EQU5## where ε S is the dielectric permittivity of said semiconductor materials in said mixing section, V bi is the built-in potential of said Schottky barrier, and q is the electrical charge of an electron.
Claim 9
Dependent Claim
43 words
A receiver according to claim 7, wherein said optical local oscillator means comprises two nearly-monochromatic light sources at two frequencies F 01 and F 02 separated in frequency by said frequency F LO and centered in frequency around said frequency F O .
Claim 10
Dependent Claim
31 words
A receiver according to claim 8, wherein said light sources at said frequencies F 01 and F 02 are stabilized by locking to two cavity modes of a reference optical resonant-cavity.
Claim 11
Dependent Claim
40 words
A receiver according to claim 7, wherein said mixer element means is positioned inside an enhancement optical resonant-cavity, whereby the total optical power absorbed by said mixer element means from said optical signal at said frequency F O is increased.
Claim 12
Dependent Claim
43 words
A receiver according to claim 10, wherein said optical local oscillator means comprises two nearly-monochromatic light sources at two frequencies F 01 and F 02 separated in frequency by said frequency F LO and centered in frequency around said frequency F O .
Claim 13
Dependent Claim
31 words
A receiver according to claim 11, wherein said light sources at said frequencies F 01 and F 02 are stabilized by locking to two cavity modes of a reference optical resonant-cavity.
Claim 14
Dependent Claim
33 words
A receiver according to claim 12, wherein said reference optical resonant-cavity is integrated with said mixer element means, said optical signal is injected through said reference optical resonant-cavity into said mixer element means.
Claim 15
Independent Claim
159 words
A method for receiving electromagnetic radiation at a frequency F S lower than approximately 10 13 Hz, comprising: providing an input optics means to collect an input signal at said frequency F S , providing an optical local oscillator means to generate an optical signal at a frequency F O higher than approximately 3×10 13 Hz, said optical signal is amplitude-modulated at a frequency F LO lower than approximately 10 13 Hz, providing a mixer element means responsive simultaneously to said frequencies F S , F O , and F LO , injecting said input signal electrically into said mixer element means and injecting said optical signal optically into said mixer element means to produce an output signal at a frequency F IF substantially equal to the difference between said frequencies F S and F LO , and providing an electronics means connected to said mixer element means to process said output signal at said frequency F IF .
Claim 16
Independent Claim
159 words
A method for receiving electromagnetic radiation at a frequency F S lower than approximately 10 13 Hz, comprising: providing an input optics means to collect an input signal at said frequency F S , providing an optical local oscillator means to generate an optical signal at a frequency F O higher than approximately 3×10 13 Hz, said optical signal is amplitude-modulated at a frequency F LO lower than approximately 10 13 Hz, providing a mixer element means responsive simultaneously to said frequencies F S , F O , and F LO , injecting said input signal electrically into said mixer element means and injecting said optical signal optically into said mixer element means to produce an output signal at a frequency F IF substantially equal to the difference between said frequencies F S and F LO , and providing an electronics means connected to said mixer element means to process said output signal at said frequency F IF .
Claim 17
Dependent Claim
50 words
A method according to claim 14, wherein said optical signal is generated by providing said optical local oscillator means comprising two nearly-monochromatic light sources at two frequencies F 01 and F 02 separated in frequency by said frequency F LO and centered in frequency around said frequency F O .
Claim 18
Dependent Claim
86 words
A method according to claim 14, wherein said input signal and said optical signal is injected into said mixer element means comprising: a metal contact, a mixing section of a thickness t and an average doping concentration d, said mixing section comprising semiconductor materials optically absorbing at said frequency F O , a Schottky barrier formed from said metal contact and said mixing section, and a contact section comprising semiconductor materials optically transparent at said frequency F O , said contact section adjoins said mixing section.
Claim 19
Dependent Claim
50 words
A method according to claim 16, wherein said optical signal is generated by providing said optical local oscillator means comprising two nearly-monochromatic light sources at two frequencies F 01 and F 02 separated in frequency by said frequency F LO and centered in frequency around said frequency F O .
Claim 20
Dependent Claim
34 words
A method according to claim 17, wherein said optical signal is stabilized by locking said light sources at said frequencies F 01 and F 02 to two cavity modes of a reference optical resonant-cavity.
Claim 21
Dependent Claim
85 words
A method according to claim 17, wherein said mixing section of said mixing element means is provided with said thickness t smaller than ##EQU6## where v n is the maximum electron-drift velocity of said semiconductor materials in said mixing section, and provided with said average doping concentration d higher than ##EQU7## where ε S is the dielectric permittivity of said semiconductor materials in said mixing section, V bi is the built-in potential of said Schottky barrier, and q is the electrical charge of an electron.
Claim 22
Dependent Claim
39 words
A method according to claim 19, wherein the total optical power absorbed by said mixer element means from said optical signal at said frequency F O is increased by positioning said mixer element means inside an enhancement optical resonant-cavity.
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