Grating-lobe-suppressed optical phased array with optimized element distribution

Zhang, Daocheng; Zhang, Fangzheng; Pan, Shilong

doi:10.1016/j.optcom.2018.03.007

Cited by 28 publications

(17 citation statements)

References 8 publications

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“…Imaging using silicon microphotonic phased arrays 29,34 has focused on narrowband devices, with single-pixel field of view with only a few broadband exceptions. 16 Narrowband devices cannot be used for low, natural light imaging or high bandwidth communication.…”

Section: Discussionmentioning

confidence: 99%

Point Source Localization with a Planar Optical Phased Array Compressive Sensor

Brown¹,

Spector²,

Moebius³

et al. 2021

Preprint

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Compressive sensing has been used to demonstrate scene reconstruction and source localization in a wide variety of devices. To date, optical compressive sensors have not been able to achieve significant volume reduction relative to conventional optics of equivalent angular resolution. Here, we adapt silicon-photonic optical phased array technology to demonstrate, to our knowledge, the first application of compressive imaging in a photonicintegrated device. Our novel sensor consists of an 8 × 8 grid of grating couplers with a spacing of 100 µm. Path-matched waveguides route to a single multimode interferometer (MMI), which mixes and randomizes the signals into 64 outputs to be used for compressed sensing. Our device is fully passive, having no need for phase shifters, as measurement matrix calibration makes the measurements robust to phase errors. For testing, we use an Amplified Spontaneous Emission (ASE) source with a bandwidth of 40 nm, centered at 1545 nm. We demonstrate simultaneous multi-point (2 sources demonstrated in this work) brightness recovery and localization with better than 10 arcsecond precision in a sub-millimeter thick form-factor. We achieve a single source recovery rate higher than 99.9% using 10 of the 64 outputs, and a 90% recovery rate with only 6 outputs, 10 times fewer than the 64 needed for conventional imaging. This planar optical phased array compressive sensor is well-suited for imaging sparse scenes in applications constrained by form factor, volume, or high-cost detectors, with the potential to revolutionize endoscopy, beam locators, and LIDAR.

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Section: Discussionmentioning

confidence: 99%

Point Source Localization with a Planar Optical Phased Array Compressive Sensor

Brown¹,

Spector²,

Moebius³

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…As shown in Figure 1, the waveguide array is connected to the grating antenna array, and the light is radiated by these grating antennas. The far field pattern of a nonuniform array is [13]:…”

Section: Design Approach Of Optical Phased Arraymentioning

confidence: 99%

“…where E 2 max−sidelobe is the intensity of the maximum side lobes and E 2 mainlobe is the intensity of the main lobe. The far field pattern of a nonuniform array is [13]:…”

Section: Design Approach Of Optical Phased Arraymentioning

confidence: 99%

A Design Approach of Optical Phased Array with Low Side Lobe Level and Wide Angle Steering Range

He¹,

Dong²,

He³

et al. 2021

Photonics

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In this paper, a new design approach of optical phased array (OPA) with low side lobe level (SLL) and wide angle steering range is proposed. This approach consists of two steps. Firstly, a nonuniform antenna array is designed by optimizing the antenna spacing distribution with particle swarm optimization (PSO). Secondly, on the basis of the optimized antenna spacing distribution, PSO is further used to optimize the phase distribution of the optical antennas when the beam steers for realizing lower SLL. Based on the approach we mentioned, we design a nonuniform OPA which has 1024 optical antennas to achieve the steering range of ±60°. When the beam steering angle is 0°, 20°, 30°, 45° and 60°, the SLL obtained by optimizing phase distribution is −21.35, −18.79, −17.91, −18.46 and −18.51 dB, respectively. This kind of OPA with low SLL and wide angle steering range has broad application prospects in laser communication and lidar system.

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“…Therefore, it is vital to obtain a higher energy density central lobe in the far-field when the total electrical input power is equal. In fact, the structure of the FLPA is similar to an optical phased array, where amplitude modulation is often used to improve the energy in central lobes [10][11][12]. Recently, Wang et al.…”

Section: Introductionmentioning

confidence: 99%

Experimental Demonstration of Central-Lobe Energy Enhancement Based on Amplitude Modulation of Beamlets in 19 Elements Fiber Laser Phased Array

Zuo

Geng

et al. 2021

IEEE Photonics J.

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Coherent beam combination of fiber laser phased array is a promising technique to achieve high-brightness laser output. In this paper, we focus on central-lobe energy enhancement of the combined beam in the far-field by theoretically and experimentally investigating the relationship between the power-in-the-bucket (PIB) of the combined beam in the far-field and the beamlets amplitude modulation in the near-field. We employ a 19-elements fiber laser phased array integrating adaptive fiber-optic collimators with a beamlet filling factor of 0.903 and achieve phase-locking and beamlet pointing correction among fiber lasers using the SPGD algorithm. The amplitude modulation applied to the tiled sub-apertures is used to control the shape of the emissive array's amplitude envelope to further change the PIB of the combined beam under the same total output power. According to theoretical analysis, the fiber laser phased array achieves PIB = 0.51 for a zero truncation ratio (Tr), which is increased to PIB = 0.57 for Tr = 1.3. Experimentally, we observe PIB = 0.49 for Tr = 0 and PIB= 0.56 for Tr = 1.3. The experimental results are in good agreement with the theoretical analysis, suggesting that the amplitude modulation is helpful for further improving the energy density of central-lobe.

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Grating-lobe-suppressed optical phased array with optimized element distribution

Cited by 28 publications

References 8 publications

Point Source Localization with a Planar Optical Phased Array Compressive Sensor

Point Source Localization with a Planar Optical Phased Array Compressive Sensor

A Design Approach of Optical Phased Array with Low Side Lobe Level and Wide Angle Steering Range

Experimental Demonstration of Central-Lobe Energy Enhancement Based on Amplitude Modulation of Beamlets in 19 Elements Fiber Laser Phased Array

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