An interferometric measurement device includes a broad-spectrum spontaneous emission light source; a measurement interferometer, receiving a light signal with input light power and delivering a modulated light signal with output light power, the modulated light signal being modulated at a modulation frequency, depending on a physical parameter to be measured and being proportional to the input light power; an optical radiation detector, receiving the modulated light signal exiting from the measurement interferometer and delivering a modulated electrical signal representative of the output light power; a filtering interferometer, insensitive to the physical parameter to be measured, having a free spectral range ISL and a finesse F selected such that an interval of frequencies, centerd around an optimal frequency f.sub.optim equal to (2k+1)ISL/2, k being a natural number, and of width Δf equal to [0.9−(3/2F)]ISL, includes the modulation frequency of the modulated light.

An interferometric measurement device includes a broad-spectrum spontaneous emission light source; a measurement interferometer, receiving a light signal with input light power and delivering a modulated light signal with output light power, the modulated light signal being modulated at a modulation frequency, depending on a physical parameter to be measured and being proportional to the input light power; an optical radiation detector, receiving the modulated light signal exiting from the measurement interferometer and delivering a modulated electrical signal representative of the output light power; a filtering interferometer, insensitive to the physical parameter to be measured, having a free spectral range ISL and a finesse F selected such that an interval of frequencies, centerd around an optimal frequency f.sub.optim equal to (2k+1)ISL/2, k being a natural number, and of width Δf equal to [0.9−(3/2F)]ISL, includes the modulation frequency of the modulated light.

Waveguide includes fork with first and second bifurcated ends coupled to loop section and separated by angle determined based on velocities of portions of quantum mechanical wavefunction of atoms traveling above waveguide. Waveguide propagates blue-detuned laser having first evanescent field that repels atoms away from waveguide and red-detuned laser having second evanescent field that attracts atoms toward waveguide, together creating potential minimum/well. Laser cooling atoms, causing atoms positioned in potential minimum/well to move toward first fork section following potential minimum/well. Atomic state initialization section initializes atomic states of atoms to known ground-state configuration. Beam splitter section splits quantum mechanical waveform of each atom above surface of diverging waveguide into first portion at first velocity that travels into first end of first fork section into first loop section and second portion at second velocity that travels into second end of first fork section into first loop section.

Waveguide includes fork with first and second bifurcated ends coupled to loop section and separated by angle determined based on velocities of portions of quantum mechanical wavefunction of atoms traveling above waveguide. Waveguide propagates blue-detuned laser having first evanescent field that repels atoms away from waveguide and red-detuned laser having second evanescent field that attracts atoms toward waveguide, together creating potential minimum/well. Laser cooling atoms, causing atoms positioned in potential minimum/well to move toward first fork section following potential minimum/well. Atomic state initialization section initializes atomic states of atoms to known ground-state configuration. Beam splitter section splits quantum mechanical waveform of each atom above surface of diverging waveguide into first portion at first velocity that travels into first end of first fork section into first loop section and second portion at second velocity that travels into second end of first fork section into first loop section.

In one embodiment of a superluminescent diode, a first diode adapted on a semiconductor die is to be forward-biased to output optical energy in response to a bias signal, and a second diode adapted on the semiconductor die is to be reverse-biased, the second diode to receive and absorb back propagating optical energy from the first diode and output a measure of the back propagating optical energy as an absorber feedback current. A comparator may be configured to compare the absorber feedback current to a reference current and output a comparison signal, and a driver control circuit coupled to the comparator may provide the bias signal based at least in part on the comparison signal. Other embodiments are described and claimed.

An atom chip (Ach) for an ultra-cold atom sensor, the atom chip includes a first pair of waveguides, a second pair of waveguides, the projections of the guides along X and the guides along Y′ in the plane XY forming, at their intersection, a first parallelogram with a centre O and having a first surface, a first conductive strip and a second conductive strip arranged such that their respective projection in the plane XY forms, at their intersection, a second parallelogram also with a centre O and having a second surface, the strips being designed to be flowed through by DC currents, an intersection between the first and the second surface being greater than or equal to 40% of the first surface.

An atom chip (Ach) for an ultra-cold atom sensor, the atom chip includes a first pair of waveguides, a second pair of waveguides, the projections of the guides along X and the guides along Y′ in the plane XY forming, at their intersection, a first parallelogram with a centre O and having a first surface, a first conductive strip and a second conductive strip arranged such that their respective projection in the plane XY forms, at their intersection, a second parallelogram also with a centre O and having a second surface, the strips being designed to be flowed through by DC currents, an intersection between the first and the second surface being greater than or equal to 40% of the first surface.

Disclosed herein are configurations and methods to produce very low loss waveguide structures, which can be single-layer or multi-layer. These waveguide structures can be used as a sensing component of a small-footprint integrated optical gyroscope. By using pure fused silica substrates as both top and bottom cladding around a SiN waveguide core, the propagation loss can be well below 0.1 db/meter. Low-loss waveguide-based gyro coils may be patterned in the shape of a spiral (circular or rectangular or any other shape), that may be distributed among one or more of vertical planes to increase the length of the optical path while avoiding the increased loss caused by intersecting waveguides in the state-of-the-art designs. Low-loss adiabatic tapers may be used for a coil formed in a single layer where an output waveguide crosses the turns of the spiraling coil.

A disk resonator is pumped by counterpropagating pump signals to produce corresponding counterpropagating Brillouin laser signals. The pump laser optical frequencies are separated by a frequency offset Δν.sub.P but excite the same nominal resonator optical mode; the Brillouin laser optical frequencies are separated by a beat frequency Δν.sub.L with 0<Δν.sub.L<Δν.sub.P. A photodetector receives the Brillouin laser signals and produces an electrical signal at the beat frequency Δν.sub.L. The frequency offset Δν.sub.P can be large so enough to prevent locking of the Brillouin laser signals onto a common Brillouin laser frequency. A signal processing system derives from the beat frequency Δν.sub.L an estimated angular velocity component of the disk optical resonator about an axis substantially perpendicular to the disk optical resonator.

A disk resonator is pumped by counterpropagating pump signals to produce corresponding counterpropagating Brillouin laser signals. The pump laser optical frequencies are separated by a frequency offset Δν.sub.P but excite the same nominal resonator optical mode; the Brillouin laser optical frequencies are separated by a beat frequency Δν.sub.L with 0<Δν.sub.L<Δν.sub.P. A photodetector receives the Brillouin laser signals and produces an electrical signal at the beat frequency Δν.sub.L. The frequency offset Δν.sub.P can be large so enough to prevent locking of the Brillouin laser signals onto a common Brillouin laser frequency. A signal processing system derives from the beat frequency Δν.sub.L an estimated angular velocity component of the disk optical resonator about an axis substantially perpendicular to the disk optical resonator.