893 results about "Optical coupler" patented technology

The invention discloses an optical frequency comb generation method and device based on Brillouin scattering and an electro-optical modulator, and belongs to the field of photoelectric measurement. The method comprises the steps that a first laser and a second laser are used for generating pump light and seed light respectively, multi-wavelength pump light is generated through a cascade electro-optical modulator, the pump light and the seed light are emitted into a Sagnac loop, an optical frequency comb is output through the forward Brillouin scattering effect of an optical fiber and the electro-optical modulator, and the seed light and the pump light are output. The polarization controller is adjusted to optimize polarization state matching of the pump light and the seed light, so that the Brillouin scattering effect reaches the maximum value. The device is composed of a laser, an electro-optical modulator, a signal generator, an optical amplifier, an optical isolator, an optical coupler, a polarization controller and an optical fiber. The optical fiber forward Brillouin scattering effect and the electro-optical modulator are combined, the optical frequency comb giving consideration to the wide frequency spectrum and the narrow interval is generated, meanwhile, the comb tooth interval of the optical frequency comb can be accurately controlled by independently adjusting the frequency of the signal generator, and accurate measurement of signals or objects is achieved.

The invention relates to a phase-sensitive optical time domain reflectometer based on multi-frequency reference switching. Continuous laser generated by a continuous laser is divided into a local path and a detection path through an optical coupler; the local path is input to the polarization coherent receiving module, the detection path is incident to a light intensity modulator driven by the signal generation circuit module, and the light intensity modulator is converted into a multi-frequency pulse laser sequence with intensity modulation; the multi-frequency pulse laser sequence enters the sensing optical fiber to be measured through the optical circulator; generated Rayleigh backscattered light and local continuous laser are subjected to beat frequency coherent receiving in a polarization coherent receiving module through a circulator; and the signal acquisition circuit adopts a demodulation algorithm to compensate phase drift and sensitivity difference of detection pulse demodulation signals with different frequencies so as to realize dynamic strain sensing. Compared with the prior art, the phase drift and the sensitivity difference between the frequencies are extracted to realize the compensation of the interleaved signals, and the method does not depend on the fixed reference frequency, so that the robustness and the adaptability of the system in a complex environment are remarkably enhanced.

Configurations for an optical coupler that includes waveguides that provide asymmetric mode confinement. The optical coupler may include first and second rib waveguides, and the width of the shoulder of at least one rib waveguide may taper to provide the asymmetric mode confinement. In some instances the shoulders of one or both rib waveguides may have different heights in a central region of the optical coupler.

An electrical transmission safety system for connection of direct current (DC) power from a DC power source to a load comprises: a connection from the power source to the load, the connection comprising a positive terminal and a negative terminal; a first solid state switch electrically connected between the power source and one of the positive terminal and negative terminal; and a switch-control isolation block comprising a first optocoupler, the first optocoupler providing electrical isolation from the power source for generating a first isolated switch-control signal in response to a switch-control input signal, the switch-control isolation block connected to provide the first isolated switch-control signal to the first solid state switch to thereby control an ON or OFF conduction state of the first solid state switch and corresponding current flow between the power source and the load through the one of the positive terminal and negative terminal.

The invention relates to a phase-sensitive optical time domain reflectometer based on a parallel frequency division multiplexing sequence. Continuous laser is divided into a local path and a detection path through an optical coupler; the local path is input to the polarization coherent receiving module, the detection path is converted into a pulse laser sequence with intensity modulation through a light intensity modulator driven by a radio frequency signal provided by the signal generation circuit module, and the radio frequency signal is composed of two frequency division multiplexing sequences with difference; the pulse laser sequence enters the sensing link to be measured to generate Rayleigh backscattered light, and the Rayleigh backscattered light and local continuous laser are subjected to beat frequency coherent receiving through a circulator; and the signal acquisition circuit is used for sampling and analyzing the interference signal, and performing frequency domain comparison on an interleaving result of the two frequency division multiplexing pulse sequences to eliminate a harmonic frequency and retain a real strain signal frequency. Compared with the prior art, the non-harmonic strain signal measurement is realized, the high-frequency response performance and the high-precision strain measurement capability are excellent, and meanwhile, the long-distance coverage capability is also realized.

The invention discloses a high-tolerance synchronous dual-band pulse laser, and relates to the field of lasers, and the laser comprises a first resonant cavity and a second resonant cavity; the first resonant cavity comprises a first pumping source and an optical annular cavity formed by sequentially connecting a first wavelength division multiplexer, a first thulium-doped optical fiber, a first optical coupler, a first isolator, a second wavelength division multiplexer, a high-nonlinearity saturable absorber, a third wavelength division multiplexer and a first polarization controller; the second resonant cavity comprises a second pumping source and an optical annular cavity which is formed by sequentially connecting a fifth wavelength division multiplexer, a second erbium-doped fiber, a second optical coupler, a second wavelength division multiplexer, a high-nonlinearity saturable absorber, a third wavelength division multiplexer, an electric control adjustable delay line, a fourth wavelength division multiplexer, a second polarization controller and a second isolator, and the fifth wavelength division multiplexer, the second erbium-doped fiber, the second optical coupler, the high-nonlinearity saturable absorber, the third wavelength division multiplexer, the electric control adjustable delay line, the fourth wavelength division multiplexer, the second polarization controller and the second isolator; and the first optical coupler and the second optical coupler respectively output synchronization pulses in the wave bands of 2 microns and 1.5 microns. The device is compact in structure, low in manufacturing cost, convenient to operate and capable of covering the mid-infrared band of 2 microns.

The invention discloses a scanning high-resolution double-optical-comb spectrum system based on Raman gain modulation. The method is suitable for real-time spectrum detection with a wide spectrum range and high spectral resolution. The system comprises a single-frequency laser and driver, an optical coupler, a mode-locked laser, a rare earth doped amplifier, a wavelength division multiplexer, a Raman gain fiber, a sample to be tested, a photoelectric detector, a data processor and a wavemeter. The single-frequency laser couples part of light to the wavemeter, and the remaining light is divided into two paths to be coupled with the two amplified mode-locked lasers to enter the Raman gain optical fiber for Raman gain modulation and is converted into high-mutual-dryness double optical combs. The double combs pass through a to-be-measured sample in a combined manner, and interference signals are measured by the photoelectric detector and received by the data processor. And meanwhile, the processor sends a tuning signal to the single-frequency laser driver, so that the double combs scan in a wide spectrum range to obtain high-resolution spectrum information. Electrical feedback locking is not needed, and high-precision spectrum acquisition with megahertz resolution in a terahertz range can be completed within a few minutes.

According to the three-dimensional stacked photoelectric co-packaging structure and the packaging method thereof provided by the invention, the three-dimensional stacked structure is formed by bonding the optical chips with C2W of the adapter plate wafer, and the optical chips can be allowed to be processed separately and then bonded on the adapter plate wafer, so that the complexity of the packaging process is reduced, and the packaging reliability is improved; besides, a bonding pad of each layer of optical chip bonding pad region is in contact connection with a part of conductive via holes of the electric interconnection region, and an upper layer optical coupling region is arranged to shrink outwards relative to a lower layer optical coupling region to expose a first optical coupler in the lower layer optical coupling region, so that the areas of the optical chips are sequentially increased from bottom to top along the thickness stacking direction of the photoelectric switching structure; the electric interconnection structure is arranged on the outer side edge of the optical chip to form an inverted pyramid shape, the electric interconnection structure is distributed on the outer side edge of the optical chip, a conductive column structure can be effectively prevented from being manufactured on the optical chip, the process complexity is reduced, meanwhile, the optical interconnection structure is also distributed on the outer side edge of the optical chip, light in the optical chip can be directly coupled to a photoelectric transmission layer, and too high efficiency loss caused by too many optical coupling times is avoided.

The invention provides a state-adjustable double-gain optical structure on a silicon substrate and a laser radar system, and relates to the technical field of laser radars. The adjustable double-gain optical structure on the silicon substrate comprises a first reflection type semiconductor optical amplifier, a second reflection type semiconductor optical amplifier, a first phase modulator, a second phase modulator, a first optical coupler, a third phase modulator, a fourth phase modulator, a second optical coupler, a first port and a second port. A reflected light electric field and a transmission light electric field are adjusted by adjusting the phase difference between the two reflection type semiconductor optical amplifiers. A laser radar system is formed by a plurality of state-adjustable double-gain optical structures on a silicon substrate, a transmitting optical phased array, a receiving optical phased array, a balanced photoelectric detector and the like, the transmitting power of the transmitting optical phased array is flexibly adjusted, meanwhile, a plurality of reflection type semiconductor optical amplifiers are adopted, the laser radar power is remarkably improved, and the laser radar system is suitable for large-scale popularization and application. And long-distance detection of the laser radar system based on the optical phased array is realized.

Integrated optical waveguides, direct-bonded waveguide interface joints, optical routing and interconnects are provided. An example optical interconnect joins first and second optical conduits. A first direct oxide bond at room temperature joins outer claddings of the two optical conduits and a second direct bond joins the inner light-transmitting cores of the two conduits at an annealing temperature. The two low-temperature bonds allow photonics to coexist in an integrated circuit or microelectronics package without conventional high-temperatures detrimental to microelectronics. Direct-bonded square, rectangular, polygonal, and noncircular optical interfaces provide better matching with rectangular waveguides and better performance. Direct oxide-bonding processes can be applied to create running waveguides, photonic wires, and optical routing in an integrated circuit package or in chip-to-chip optical communications without need for conventional optical couplers. An example wafer-level process fabricates running waveguides, optical routing, and direct-bonded optical interconnects for silicon photonics and optoelectronics packages when two wafers are joined.

The invention discloses a charging management circuit and a charger. The charging management circuit comprises a flyback converter, a first sampling feedback module, a second sampling feedback module and an optocoupler. The first sampling feedback module comprises a comparator, a first switch unit, a thermosensitive voltage dividing unit and a current sampling resistor. The duty ratio of a PWM chip is controlled through an optocoupler to achieve constant-current charging in the first charging stage. The resistance of the thermosensitive voltage dividing unit is increased when the temperature rises, the charging current is automatically reduced, and temperature self-adaptive protection is achieved. And when the charging current is reduced to a preset value, the second sampling feedback module takes over the control optocoupler to realize constant-voltage charging in a second charging stage. Constant-current and constant-voltage two-stage charging can be achieved, the function of automatically adjusting the charging current through the temperature is achieved, the charger is effectively prevented from being overheated in the high-temperature environment, and the safety of the charger and a battery is protected.

Apparatuses, systems and methods for optical coupling, optical integration, electro-optical coupling, and electro-optical packaging are described herein. Optical couplers may comprise various optical elements (e.g., mirrors as described herein) to relax optical assembly requirements and improve producibility. Optical couplers may improve fiber-to-chip, fiber-to-fiber and chip-to-chip optical connection. Optical couplers and optical components may be used to improve integration of, connection of, and / or packaging of optical systems and / or components with electrical systems and / or components.

The invention discloses an intelligent insulation parameter dynamic monitoring and regulation system based on a GD32 microcontroller, and belongs to the field of power electronic insulation monitoring. According to the system, a distributed monitoring network is constructed by taking GD32 as a core processor, a multi-channel time-sharing sampling and dynamic impedance measurement algorithm is integrated, GA / GB dual-channel independent sampling is realized by virtue of a state machine, and the sampling efficiency is improved by 80% compared with that of a traditional scheme. A programmable resistance network and a low-noise operational amplifier are adopted, 1 pF to 100 nF impedance matching and 5-200-time dynamic gain adjustment are achieved, an optical coupler switching dynamic impedance measurement method is originally created, four sets of voltage are adopted for time-sharing conduction of a solid-state relay, and 1.5% high precision is achieved through an improved voltage division model. LC-pi type filtering is adopted at a signal input end, and the high-frequency noise suppression ratio is larger than 20 dB; and a CAN module is newly added, so that a CAN2.0B extension frame and an adjustable Baud rate of 10k-1Mbps are supported. Actual measurement shows that the system can measure 10-65M omega insulation resistance in new energy and rail transit scenes, the dynamic response is smaller than or equal to 200ms, the system is suitable for the fields of medical equipment, industrial sensors and the like, and the overall performance is improved by three times compared with that of a traditional scheme.

The invention relates to a chip and a module for optical interconnection, and a device and a system using the optical interconnection module. The chip comprises photon integrated circuit sub-modules, each sub-module comprises a plurality of first optical switching units, and each first optical switching unit is configured to selectively output an optical signal input by a first optical input port of the first optical switching unit through any optical output port; an on-chip optical switch which is optically connected with the first optical switching unit and is configured to select an output port to output an optical signal input by any one optical input port of the on-chip optical switch; a plurality of modulators optically connected to the first optical switching unit; a plurality of detectors, at least a portion of which is optically connected to the on-chip optical switch; a plurality of first optical couplers configured to optically connect the first optical switching unit with a first external optical fiber array; and a second optical coupler in optical connection with at least a portion of the detector and configured to transmit the optical signal from the second external optical fiber array to the portion of the detector.

An electro-optical integrated circuit comprising an optical transmitter and an optical receiver is disclosed in which a monolithically integrated electro-absorption modulated laser (EML) can operate bi-directionally in both transmitter and receiver modes. Vertically stacked waveguides for lasers and electro-absorption modulators (EAMs) are provided. The laser and the EAM are optically coupled through a transverse conical vertical optical coupler. The EML includes monolithically integrated electronic circuitry, such as drivers and control electronics for driving the laser as the EML and the EAM in the transmitter mode. The control circuit includes a transimpedance amplifier (TIA). The EAM has a first portion and a second portion that may be independently biased. In receiver mode, the laser current is reduced near a threshold, a first portion of the EAM is biased to absorb residual laser light, while a second portion of the EAM provides photocurrent to the TIA as a photodiode receiver.

The invention discloses a digital quantity output control circuit and method integrating overcurrent instantaneous protection and delay recovery functions. The circuit is mainly composed of a sampling module, a delay module, a voltage following module, an alarm module, an optical coupler isolation module and a typical digital output switch control module. When an over-current phenomenon is detected, the protection circuit can respond quickly, the circuit is cut off immediately to realize protection, and an alarm signal is output synchronously. Thereafter, the protection state will last for a preset delay time. During the period, the processor can monitor an alarm signal and output a circuit turn-off control signal according to the alarm signal. And after the delay time ends, the protection delay circuit automatically recovers to an initial state, and at the moment, the processor takes over signal output control according to the control logic. According to the invention, over-current instantaneous protection and delay recovery functions of the digital output circuit and smooth switching controlled by the processor are successfully realized, and safety risks caused by over-current faults are effectively avoided.

An OCT instrument comprising: an optical coupler which generates signal light and reference light from a swept narrowband light source; a detector which samples a time-varying interference signal based on the reference light and signal light returned from a sample; an adjustable optical frequency shifter which: generates a first sideband light by adjusting an optical frequency of the reference light, such that the detector unit samples a first time-varying interference signal resulting from an interference between the sideband light and the returned signal light; and maintains the optical frequency of the reference light such that the detector unit samples a second time-varying interference signal resulting from an interference between the reference light and the returned signal light. The OCT instrument generates a respective axial depth profile of the sample based on each of the sampled first time-varying interference signal and the sampled second time-varying interference signal.

The invention relates to a sweep frequency optical frequency comb generation system and a generation method. Fourier mode locking is realized through a Fourier mode locking photoelectric oscillator system. The sweep frequency optical frequency comb generation system is a closed Fourier mode-locked laser loop which is composed of a first optical amplifier, an optical fiber isolator, a broadband filter, a polarization controller, a thin film lithium niobate optical chip, a signal generator, a dispersion compensation optical fiber and a first optical coupler; and a photoelectric oscillator loop is formed by a second optical coupler, a single-mode delay optical fiber, a second optical amplifier, a photoelectric detector, a narrow-band filter, a low-noise amplifier and an electric power divider. Time domain active mode locking and Fourier mode locking are carried out on the laser resonant cavity at the same time, synchronous modulation of multiple optical frequency comb modes is achieved, sweep frequency optical frequency comb signals with high repetition frequency, high modulation speed, high coherence length and high output power are generated, and tunable optical frequency comb and high-quality high-frequency microwave signal output can be provided at the same time.

Systems, methods, and computer program products are described for a redundant external laser source in optical systems (e.g., CPO systems). An example system may include a plurality of ELS units, a RELS unit, an optical switch, and a plurality of optical couplers, and a control unit. The control circuit may be configured to detect an operational failure of a first ELS unit. In response to detecting such a failure, the control circuit may configure the RELS unit to replace the first ELS unit and, using the optical switch, substitute the first ELS unit with the RELS unit. Such a configuration ensures continuous system performance by dynamically replacing failing ELS units with redundant ELS units, thereby reducing downtime and enhancing the reliability of the optical communication system.

The technology is generally directed to a coherent optical system that performs phase folding for one-dimensional coherent optical signals using a first optical coupler configured to output a first signal portion and a second signal portion, a second optical coupler to receive the first signal portion through a first branch and the second signal portion through a parallel second branch, and a phase-folding time delay unit including at least a first time delay component positioned on the first branch and a second time delay component positioned on the second branch. An output of the second optical coupler is a phase-folded version of the one-dimensional modulated optical signal that is capable of being demodulated by a one-dimensional vector receiver.

Apparatuses, systems and methods for optical coupling, optical integration, electro-optical coupling, and electro-optical packaging are described herein. Optical couplers may comprise various optical elements (e.g., mirrors as described herein) to relax optical assembly requirements and improve producibility. Optical couplers may improve fiber-to-chip, fiber-to-fiber and chip-to-chip optical connection. Optical couplers and optical components may be used to improve integration of, connection of, and / or packaging of optical systems and / or components with electrical systems and / or components.

The present invention relates to the technical field of data communications, and provides an apparatus and method for rapid recovery from failures of some devices in an optical data switching or computing device cluster. A management device confirms the identifier m of a second-layer device that sends an alarm message; on the basis of a pre-established mapping relationship between the identifier m of the second-layer device and an optical path port Pm in each protection optical switch device, the management device controls an optical switch in each protection optical switch device in the protection optical switch array, such that a common port thereof is connected to the optical path port Pm, thereby replicating an optical signal, imported from a first-layer device library into the second-layer device m, to a second-layer redundant device by means of the optical switch in each protection optical switch device and an optical coupler m. In the present invention, when some devices fail, functions of the devices can be rapidly switched to a redundant device, thereby reducing failure recovery time and saving cluster device resources.

Apparatuses, systems and methods for optical coupling, optical integration, electro-optical coupling, and electro-optical packaging are described herein. Optical couplers may comprise various optical elements (e.g., mirrors as described herein) to relax optical assembly requirements and improve producibility. Optical couplers may improve fiber-to-chip, fiber-to-fiber and chip-to-chip optical connection. Optical couplers and optical components may be used to improve integration of, connection of, and / or packaging of optical systems and / or components with electrical systems and / or components.

The application provides an optical coupler applied to the field of optical communication. The optical coupler comprises a buried layer, a support layer, a waveguide layer and an upper cladding layer. In the height direction, the support layer is between the buried layer and the waveguide layer. The waveguide layer is between the support layer and the upper cladding layer. In the width direction, the waveguide layer and the support layer are inside the upper cladding layer. The materials of the waveguide layer and the support layer are different. In the application, the support layer is inside the upper cladding layer. Therefore, the upper cladding layer is on both sides of the support layer. The energy of the optical signal can be dispersed on both sides of the support layer, so that the degree of uneven energy distribution near the center of the waveguide layer is reduced, and the coupling loss of the optical coupler is reduced.

The invention relates to the technical field of electronic detonator detonating, and particularly discloses an electronic detonator detonating agent automatic lifting method test device, which comprises an electronic detonator detonating agent ignition test platform, at least one ignition plate test row groove, an electronic detonator detonating agent ignition plate base plate, an electronic detonator detonating agent automatic lifting method test platform and an electronic detonator detonating agent automatic lifting method test platform, each row of electronic detonator detonating agent ignition plate substrates bear a plurality of ignition plates dipped with detonating agents; the anti-explosion electronic detonator test isolation cover is arranged above the electronic detonator detonating agent ignition test platform and is provided with a plurality of independent empty slots for independently placing the ignition plates; the dual-mode signal detection unit comprises an optocoupler signal sensor receiving device and a vibration signal sensor receiving device which are respectively used for detecting an explosion optical signal and a vibration wave signal; the device is suitable for meeting the batch test requirements of ignition capacitors, transduction elements and exploder agents of various electronic control modules, the test efficiency is effectively improved, and the test safety and reliability are guaranteed.

The invention relates to polymerizable liquid crystal formulations (as a subcategory of liquid crystal material), especially to polymerizable ink formulations for inkjet printing, which are preferably PFAS-free (for enabling the reduction of perfluorocarbons and providing an environment friendly material), and which are comprising one or more polymerizable mesogenic compounds, also known as reactive mesogens (RMs), and one or more organic solvents selected from the group of aromatic ester and aromatic or aliphatic diester solvents, to polymers and polymer films obtained from such formulations, and to the use of the formulations, polymers and polymer films in optical or electrooptical components or devices, especially for digital optics or augmented reality or virtual reality (AR / VR) applications like polarizers, optical compensators, reflective films, diffraction or surface gratings, Bragg polarization gratings (Bragg PG), polarization volume gratings (PVG), polarization volume holograms (PVH), Pancharatnam Berry (PB) gratings, nonmechanical beam steering elements, optical waveguides, optical couplers, optical combiners, polarization beam splitters, partial mirrors, lenses or PB lenses.

The invention discloses a micro-displacement measurement system based on dual-wavelength medium metasurface conjugate vortex light interference, and relates to the technical field of optical displacement measurement, the micro-displacement measurement system comprises an optical coupler, a metasurface, an objective lens and a first beam splitter, the input end of the optical coupler is connected with a first laser and a second laser at the same time; two parts of light output by the first beam splitter are respectively input into a measuring arm and a reference arm, the measuring arm comprises a Dove prism, a second beam splitter, a measuring quarter-wave plate and a measuring reflector, the reference arm comprises a third beam splitter, a reference quarter-wave plate and a reference reflector, light reflected by the measuring reflector and the reference reflector is input into a fourth beam splitter, and light reflected by the fourth beam splitter is input into a fourth beam splitter. The fourth beam splitter combines the two beams of light and inputs the combined light to the CCD camera; and the computer processes the interference image to obtain the displacement of the to-be-measured object. Through the metasurface and dual-wavelength theory, the problems that a displacement measurement system is large in size and small in measuring range are solved at the same time.

The invention relates to the technical field of voltage detection, and specifically provides a voltage detection circuit and method, and a household appliance. The voltage detection circuit comprises a rectification unit used for rectifying alternating current output by an alternating current power supply; the current limiting unit is used for limiting the rectified current within a preset range; the detection resistor unit is used for receiving the current after current limiting; the optical coupler unit is used for being switched on or switched off according to the voltage at the two ends of the detection resistor unit; the control unit is used for controlling an output level signal according to the voltage at the two ends of the detection resistor unit; and the switch unit is used for switching on or switching off the connection with a load in response to the level signal. Zero-cross detection and voltage detection of the washing machine are combined into one, the cost is reduced, the voltage of the mains supply can be judged, and load protection can be carried out.

The invention relates to a packaging structure and a preparation method thereof, and relates to the technical field of semiconductors, in the packaging structure and the preparation method thereof, a first rewiring layer comprises a wiring layer and a dielectric layer, the orthographic projection of the wiring layer on a carrier plate is not overlapped with the orthographic projection of an optical coupler on the carrier plate, namely, the wiring layer does not shield an optical window of the optical coupler, and the dielectric layer is arranged on the dielectric layer; a light-transmitting dielectric material column is formed on the side, away from the carrier plate, of the first rewiring layer, the orthographic projection of the light-transmitting dielectric material column on the carrier plate is overlapped with the orthographic projection of the optical coupler on the carrier plate, at the moment, an optical window of the optical coupler is shielded by the light-transmitting dielectric material column, and the optical window cannot be polluted when the second packaging layer is prepared subsequently; the second packaging layer exposes the light-transmitting dielectric material columns, and the optical coupler achieves vertical optical coupling through the light-transmitting dielectric material columns.

An optical sensor includes a probe fiber Bragg grating (FBG) coupleable to a light source, the probe fiber Bragg grating defining a probe spectrum and arranged to provide a probe light signal corresponding to the probe spectrum. A sensing fiber Bragg grating (FBG) defines a sensing spectrum. A spectral shift in the sensing spectrum is responsive to a change in at least one external parameter acting on the sensing fiber Bragg grating. The optical coupler couples the probe optical signal with the sensing fiber Bragg grating to output a spectrally overlapped optical signal. An intensity level of the spectrally overlapping light signal corresponds to an overlap between the detection spectrum and the sensing spectrum. And an optical power regulator coupled to the optical coupler, the optical power regulator arranged to adjust a baseline of the intensity level to change a sensitivity of the optical sensor.