PHOTONIC RF DOWN-CONVERTER BASED ON OPTOMECHANICAL OSCILLATION

• US 20090263137A1
• Filed: 01/26/2009
• Published: 10/22/2009
• Est. Priority Date: 01/25/2008
• Status: Active Grant

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Hossein-Zadeh, Mani, Vahala, Kerry J.
• Granted Patent: US 9,246,529 B2
• Time in Patent Office: Days
• US Class Current: 398/115
• CPC Class Codes: G02F 1/0128 based on electro-mechanical, magneto-mechanical, elasto-optic effects
• CPC Class Codes: G02F 1/21 by interference
• CPC Class Codes: G02F 2/002 using optical mixing
• CPC Class Codes: G02F 2203/055 wavelength filtering
• CPC Class Codes: G02F 2203/15 involving resonance effects, e.g. resonantly enhanced interaction
• CPC Class Codes: H04B 1/30 for homodyne or synchrodyne receivers demodulator circuits H03D1/22
• CPC Class Codes: H04B 2210/006 Devices for generating or processing an RF signal by optical means

Abstract

An all optical radio frequency converter. The invention relates to a microtoroid optomechanical oscillator that can provide a local oscillation frequency and a mixing functionality. The microtoroid optomechanical oscillator can be fabricated from a silica-on-silicon wafer. When an input optical signal having an optical carrier frequency carrying a modulated RF signal representing information is applied to the microtoroid optomechanical oscillator, a signal including the baseband information modulated on the optical carrier is provided as output. The output signal can be detected with a photodetector. Information carried by the optical signal can be recorded and/or displayed to a user. Injection locking of the microtoroid optomechanical oscillator can be accomplished by providing a signal of suitable frequency. The frequency and the phase of operation of the microtoroid optomechanical oscillator can be locked to the respective frequency and phase of the injected locking signal.

Claims

1. An all-optical RF frequency converter, comprising:

a microtoroid optomechanical oscillator configured to provide a RF local oscillation frequency and configured to provide a RF mixing functionality, said microtoroid optomechanical oscillator having an optical input port configured to receive an optical signal having an optical frequency carrier and an RF frequency sub-carrier that carries a lower frequency single-tone, modulated thereon, and an optical output port configured to provide an optical signal modulated with said low frequency single-tone without said RF carrier.

2. The all-optical RF frequency converter of claim 1, wherein said optical input port configured to receive an optical signal is an optical input port configured to receive an optical signal comprising an injection frequency component that is configured to lock at least one of a frequency and a phase of said microtoroid optomechanical oscillator to a respective at least one of a frequency and a phase of said injection frequency component.

3. The all-optical RF frequency converter of claim 2, wherein, in response to the provision of an optical signal comprising an injection frequency component that is configured to lock at least one of a frequency and a phase of said microtoroid optomechanical oscillator to a respective at least one of a frequency and a phase of said injection frequency component at said optical input port, said microtoroid optomechanical oscillator is constrained to operate at a respective at least one of a frequency and a phase of said injection frequency component.

4. The all-optical RF frequency converter of claim 1, wherein said microtoroid optomechanical oscillator comprises silica.

5. The all-optical RF frequency converter of claim 1, in combination with:

a signal source configured to provide a signal representing information to said input port of said microtoroid optomechanical oscillator, said signal comprising an optical carrier frequency and information provided in an RF signal having a RF carrier and baseband frequency where said RF carrier frequency is equal to an optomechanical oscillation frequency of said microtoroid optomechanical oscillator;

a photodetector having a bandwidth matched to said baseband frequency, said photodetector configured to receive an output signal from said output port of said microtoroid optomechanical oscillator, and configured to provide as output an electrical signal representative of said information; and

an electrical apparatus configured to receive said electrical signal representative of said information and configured to perform a selected one of recording said information and displaying said information.

6. The all-optical RF frequency converter of claim 1, wherein said all-optical RF frequency converter is configured to receive an optical signal having an optical frequency carrier and an RF frequency sub-carrier that carries a lower frequency single-tone representing information modulated thereon, in combination with:

a photodetector having a bandwidth matched to said baseband frequency, said photodetector configured to receive an output signal from said output port of said microtoroid optomechanical oscillator, and configured to provide as output an electrical signal representative of said information; and

an electrical apparatus configured to receive said electrical signal representative of said information and configured to perform a selected one of recording said information and displaying said information.

7. The all-optical RF frequency converter of claim 6, in combination with said photodetector and said electrical apparatus, wherein said combination comprises an RF receiver.