US 2002/0118439 A1 · Optical frequency synthesizing structure

Abstract

An Optical Frequency Shifter (Shifter) enables all-optical frequency translation to be imparted on a data-carrying Input Optical Signal (Input Signal). The Shifter includes a first difference-frequency-mixer for achieving quasi-phase-matching between a first pump channel, the Input Signal and an Intermediate Signal. A second difference-frequency-mixer is employed for achieving quasi-phase-matching between a second pump signal, the intermediate signal and a converted signal. A frequency shift discriminates the input signal from the output signal wherein the value of the frequency shift is proportional to the difference in frequencies of the first pump signal and the second pump signal. In this fashion, the value of the frequency shift in independent of the frequency of the input signal. A multiple of Input Signals may be coupled into the Shifter and may be simultaneously shifted to a multiple of respective converted signals wherein the frequency shift has a constant value and discriminates each input signal from each respective converted signal. The Shifter may employ cascaded second harmonic generation (SHG) and difference frequency generation (DFG) thereby enabling the use of pump sources having frequencies generally in the proximity of the frequencies of the Input Signal and Converted Signal. In this fashion, first and second sub-harmonic pump signals may be quasi-phase-matched by the Shifter for achieving SHG thereby generating said first and second pump signals. A plurality of Shifters may be coupled to each other, thereby enabling a plurality of frequency translations to be imparted on the Input Signals.

Claims84

Dependent claims

An optical frequency shifter capable of performing all-optical frequency translation comprising:

a first stage including a first nonlinear optical material having a first effective nonlinearity;
and
a second stage including a second nonlinear optical material having a second effective nonlinearity;
said first effective nonlinearity having a first spatial distribution in said first nonlinear optical material such that a first nonlinear optical interaction is achieved between a first pump channel having a first pump frequency, a signal channel having a signal frequency, and an intermediate channel having an intermediate frequency;
said second effective nonlinearity having a second spatial distribution in said second nonlinear optical material such that a second nonlinear optical interaction is achieved between a second pump channel having a second pump frequency, said intermediate channel and a converted channel having a converted frequency;
such that a shift frequency differentiates said signal frequency from said converted frequency.

3 more elements

An optical frequency shifter comprising:

a plurality of N optical frequency translation stages, with each optical frequency translation stage indexed by an integer n, n=0, . . . N, and with each optical frequency translation stage having an input port, and an output port, with the optical frequency translation stage for receiving an input signal at the input port and for translating a received input signal into a translated output signal provided by the output port, with the translated output signal having a frequency equal to an input signal frequency translated by a frequency equal to 2n Δ, where Δ is a frequency shift having a selected value;
and
an input signal coupling structure for coupling the input port of an nth optical frequency translation stage to the output ports of all optical frequency translation stages preceding the nth optical stage.

A method for synthesizing a plurality of optical frequencies comprising the steps of:

receiving an input signal having an input signal frequency;
performing a first translation of a frequency shift of Δ on the input signal to generate a first translated signal having a frequency translated from the input signal frequency by Δ;
performing a second translation of a frequency shift of 2Δ on both the input signal and the first translated signal to generate second and third translated signals translated from the input signal frequency by 2Δ and 3Δ;
and
sequentially performing n subsequent translations, n being an integer equal to 3, . . . , N, with the nth translation translating the frequency of the input signal and all previously generated translated signals by a frequency shift of 2nΔ to generate 2n translated signals translated from the input signal frequency by nΔ, n+1Δ, n+2Δ, . . . , 2n−2Δ, 2n−1Δ.

2 more elements

Dependencies are inferred from the claim text.

Optical frequency synthesizing structure

Life of this patent

Optical frequency synthesizing structure

Life of this patent

Abstract

Claims84