Search query: Phase-Controlled Apertures Using Heterodyne Optical Phase-Locked Loops

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abstract: In this letter, we demonstrate the use of an electronic feedback scheme using a voltage controlled oscillator (VCO) to control the optical phase of individual semiconductor lasers (SCLs) phase locked to a common reference laser using heterodyne optical phase locked loops (OPLLs) The outputs of two external cavity SCLs phase locked to a common reference laser are coherently combined, and the variation in the relative optical path lengths of the combining beams is corrected by dynamically changing the phase of the offset radio frequency signal fed into one of the OPLLs by means of a VCO. A stable power combination efficiency of 94% is achieved. This inherently different method of phase control, i.e. electronic rather than the use of electrooptic crystals, is deemed essential for new applications involving coherent optoelectronics.
author_names: Naresh Satyan

Wei Liang

Firooz Aflatouni

Amnon Yariv

Anthony S Kewitsch

George Rakuljic

Hossein Hashemi
title: Phase Controlled Apertures Using Heterodyne Optical Phase Locked Loops
venue: IEEE Photonics Technology Letters
year: 2008

abstract: We design and experimentally demonstrate two chip scale and agile heterodyne optical phase locked loops (OPLLs) based on two types of InP based photonic integrated coherent receiver circuits. The system performance of the first generation OPLL was improved in terms of offset locking range, and power consumption with the use of a power efficient and compact photonic integrated circuit (PIC) The second generation PIC consists of a 60 nm widely tunable Y branch laser as a local oscillator with a 2 x 2 multimode interference (MMI) coupler and a pair of balanced photodetectors. This PIC consumes only 184 mW power in full operation, which is a factor of 3 less compared to the first generation PIC. In addition, the sensitivity of these OPLLs was experimentally measured to be as low as 20 mw. A possible solution to increase the sensitivity of these OPLLs is also suggested.
author_names: Arda Simsek

Shamsul Arafin

Seong-Kyun Kim

Gordon Morrison

Leif A Johansson

Milan L Mashanovitch

Larry A Coldren

Mark J W Rodwell
title: Evolution of Chip Scale Heterodyne Optical Phase Locked Loops Toward Watt Level Power Consumption
venue: Journal of Lightwave Technology
year: 2018

abstract: We demonstrate a homologous heterodyne optical phase locked loop for free spectral range measurement of a fiber ring resonator. In this loop, the frequency noise within the 10 Hz bandwidth is reduced by more than 40 dB from 147.350 to 0.014 Hz, and the power spectral density of the frequency noise reaches 7.69x10 8 Hz2/Hz at 10 Hz. Finally, the relative measurement accuracy of 1.39x10 9 is achieved by this loop and the free spectral range coefficient of thermal expansion is measured as 174.1+ 0.2 Hz/degC with a cavity finesse of 26.65. This work provides a method to measure free spectral range by tracking the resonance modes of the resonator and reducing frequency noise, especially for two signals with frequency offset.
author_names: Chunqi Zhang

Lishuang Feng

Hongchen Jiao

Ning Liu

Yonggui Zhang

Xiao Wang
title: Free spectral range measurement using homologous heterodyne optical phase locked loop based on acousto optic modulation.
venue: Applied optics
year: 2019

abstract: We design and experimentally demonstrate a highly efficient coherence transfer based on composite optical phaselocked loop comprising multiple feedback servo loops. The heterodyne offset locking is achieved by conducting an acousto optic frequency shifter in combination with the current tuning and the temperature controlling of the semiconductor laser. The adaptation of the composite optical phase locked loop enables the tight coherence transfer from a frequency comb to a semiconductor laser in a fully dynamic manner.
author_names: Weilin Xie

Yi Dong

Fabien Bretenaker

Hongxiao Shi

Qian Zhou

Zongyang Xia

Jie Qin

Lin Zhang

Xi Lin

Weisheng Hu
title: Efficient dynamic coherence transfer relying on offset locking using optical phase locked loop
venue: International Conference on Optical Instruments and Technology
year: 2018

abstract: 2.1 Phase locked loop principle Phase locked loop (PLL) is an automatic feedback control electronic device. It contains three basic components as shown in Fig. 2.1. A. A phase detector (PD) B. A loop filter (low pass filter) C. A voltage controlled oscillator (VCO) Fig. 2.1 is the simplest form of a phase locked loop. But, in practice a more elaborate arrangement consisting of heterodyne loops, band pass limiters and acquisition aids can be used, yet the behavior of the complicated arrangement of practical phase locked loops can be explained using the same model. The phase sensitive detector is a multiplicative device, the purpose of which is to produce an output voltage as a function of the instantaneous phase difference between the reference input and the output of the VCO. The frequency of VCO can be modulated in accordance with an input voltage. The PLL operates in the following way.
title: A Brief Review on Remote Carrier Signal Generation and Optical Reception using Optical Phase Locked Loop and Related Phenomena
year: 2016

abstract: Optical phase locked loops (OPLL's) are needed for synchronous homodyne receivers [l] [4] We constructed a stable optical phase locked loop with miniature diode pumped Nd:YAG ring lasers [5] Using our loop, we demonstrated a 140 Mb/s PSK synchronous homodyne experiment with the sensitivity of 25 photons/bit1. To the best of our knowledge this is the highest sensitivity demonstrated with any optical communication system to date2. In addition, we demonstrated a 560 Mb/s PSK synchronous heterodyne experiment with the sensitivity of 124 photons/bit. We investigated, for the first time, the impact of the finite intermediate frequency (IF) on heterodyne system performance and show that an IF of at least twice the bit rate is needed for a neglibly small penalty.
author_names: Leonid G Kazovsky

Daphne Atlas
title: PSK Synchronous Heterodyne and Homodyne Experiments Using Optical Phase Locked Loops
year: 1990

abstract: We demonstrate a coherent phase transfer via a 224 km cascaded fiber link comprising two 112 km links stabilized by two phase locking loops, respectively. The optical signal is regenerated employing heterodyne optical phase locking (HOPL) after the first 112 km transfer. With a gain of more than 50 dB, the HOPL is capable of tracking the frequency of the incoming carrier with a fluctuation of 0.48 mHz and preserving the instability of the incoming laser to 6x10 20 at 1000 s. The phase noise cancellation of each span is investigated, and the out loop transfer instability of the 224 km link reaches 7.7x10 19 at 10,000 s. The relation between the transfer instability of each span and that of the whole link is also deduced in the paper, in agreement with experimental results of the 224 km link.
author_names: Xuemei Deng

Jie Liu

Qi Zang

Dongdong Jiao

Jing Gao

Xiang Zhang

Dan Wang

Ruifang Dong

Tao Liu
title: Coherent phase transfer via fiber using heterodyne optical phase locking as optical amplification.
venue: Applied optics
year: 2018

abstract: The performance of an Allan variance measuring system was drastically improved by employing time interval analysis incorporating a beat frequency method. It was used to evaluate the performance of a heterodyne optical phase locked loop with a very low optical frequency tracking error of 0.4 mHz at the integration time of 70 s. Advantages of the system are precise measurement for highly stable frequency sources with good reproducibility and simple structure
author_names: C H Shin

Motoichi Ohtsu
title: Improved Allan variance real time processing system to measure frequency tracking error of heterodyne optical phase locked loops
year: 1990

abstract: Optical frequency synthesizers have widespread applications in optical communication, sensing, and ranging systems. These synthesizers typically consist of an electro optical phase locked loop (EOPLL) that phase locks a widely tunable laser (TL) to the teeth of a highly stable optical frequency comb. In this paper, a partially integrated optical frequency synthesizer is reported, where a stable and low noise frequency comb is used as the optical reference. In the proposed architecture, frequency synthesis is done in two phases. In a coarse tuning phase, a widely tunable distributed Bragg reflector laser is continuously tuned by adjusting its mirrors and phase section currents. While the laser is being tuned, an indexing system detects and counts the number of passing comb teeth. Coarse tuning is concluded when the TL reaches the target comb tooth. Following the coarse tuning phase, a heterodyne integrated EOPLL phase locks the TL to the selected comb tooth. Under the phase lock condition, fine frequency tuning is performed by adjusting the frequency of an RF local oscillator. The proposed synthesizer has the capability of synthesizing optical frequencies over a 5 THz range with a coarse tuning speed of 0.5 THz/s and coarse and fine tuning resolutions of 20 MHz and less than 1 Hz, respectively.
author_names: Farshid Ashtiani

Pouria Sanjari

Mohamad Hossein Idjadi

Firooz Aflatouni
title: High Resolution Optical Frequency Synthesis Using an Integrated Electro Optical Phase Locked Loop
venue: IEEE Transactions on Microwave Theory and Techniques
year: 2018

author_names: Yasuhiro Okamura

Masafumi Koga

Atsushi Takada
title: First demonstration of phase sensitive gain stabilization by using heterodyne Costas optical phase locked loop
year: 2016