The application of reciprocity principles in optics has a long history that goes back to Stokes, Lorentz, Helmholtz and others. Moreover, optical applications need to be seen in the context of applications of reciprocity in particle scattering, acoustics, seismology and the solution of inverse problems, generally. In some of these other fields vector wave propagation is, as it is in optics, of the essence. For this reason the simplified approach to light wave polarization developed by, and named for, Jones is explored initially to see how and to what extent it encompasses reciprocity. The characteristic matrix of a uniform dielectric layer, used in the analysis of interference filters and mirrors, is reciprocal except when the layer is magneto-optical. The way in which the reciprocal nature of a characteristic matrix can be recognized is discussed next. After this, work on the influence of more realistic attributes of a dielectric stack on reciprocity is reviewed. Some of the numerous technological applications of magneto-optic non-reciprocal media are identified and the potential of a new class of non-reciprocal components is briefly introduced. Finally, the extension of the classical reciprocity concept to systems containing components that have nonlinear optical response is briefly mentioned.

https://iopscience.iop.org/article/10.1088/0034-4885/67/5/R03/pdf

Reciprocity in optics

Traffic patterns in access networks have evolved from voice- and text-oriented services to video- and image-based services. This change will require new access networks that support high-speed (> 100 Mb/s), symmetric, and guaranteed bandwidths for future video services with high-definition TV quality. To satisfy the required bandwidth over a 20-km transmission distance, single-mode optical fiber is currently the only practical choice. To minimize the cost of implementing an FTTP solution, a passive optical network (PON) that uses a point-to-multipoint architecture is generally considered to be the best approach. There are several multiple-access techniques to share a single PON architecture, and the authors addressed several of these approaches such as time-division multiple access, wavelength-division multiple access, subcarrier multiple access, and code-division multiple access. Among these multiple techniques, they focus on time-division multiplexing (TDM)-PON and wavelength-division multiplexing (WDM)-PON, which will be the most promising candidates for practical future systems. A TDM-PON shares a single-transmission channel with multiple subscribers in time domain. Then, there exists tight coupling between subscribers. A WDM-PON provides point-to-point optical connectivity using a dedicated pair of wavelengths per user. While a TDM-PON appears to be a satisfactory solution for current bandwidth demands, the combination of future data-rate projections and traffic patterns coupled with recent advances in WDM technology may result in WDM-PON becoming the preferred solution for a future proof fiber-based access network

/pdf/fiber-to-the-home-using-a-pon-infrastructure-6dxgo8zxek.pdf

Fiber to the Home Using a PON Infrastructure

The main bandwidth bottleneck in today's networks is in the access segment. To address that bottleneck, broadband fiber access technologies such as passive optical networks (PONs) are an indispensable solution. The industry has selected time-division multiplexing (TDM) for current PON deployments. To satisfy future bandwidth demands, however, next-generation PON systems are being investigated to provide even higher performance. In this paper, we first review current TDM-PONs; we designate them as generation C. Next, we review next-generation PON systems, which we categorize into C+1 and C+2 generations. We expect C+1 systems to provide economic near-term bandwidth upgrade by overlaying new services on current TDM-PONs. For the long term, C+2 systems will provide more dramatic system improvement using wavelength division multiplexing technologies. Some C+2 architectures require new infrastructures and/or equipment, whereas others employ a more evolutionary approach. We also review key enabling components and technologies for C+1 and C+2 generations and point out important topics for future research.

/pdf/next-generation-optical-access-networks-41pmztcn8d.pdf

Next-Generation Optical Access Networks

It is anticipated that more than 75 Mb/s per subscriber is required for the convergence service such as triple-play service (TPS) Among several types of high-speed access network technologies, wavelength-division-multiplexing passive optical network (WDM-PON) is the most favorable for the required bandwidth in the near future Furthermore, WDM technologies, such as athermal arrayed-waveguide grating (AWG) and low-cost light source, have matured enough to be applied in the access network In this paper, the authors propose and implement a WDM-PON system as a platform for TPS The system employs an amplified spontaneous emission (ASE)-injected Fabry-Pe/spl acute/rot laser diode scheme It has 32 channels of 125 Mb/s and adopts Ethernet as Layer 2 Multicast and virtual local area network features are used for the integration of services such as Internet protocol high-definition broadcast, voice-over Internet protocol, video on demand, and video telephone The services were demonstrated using the WDM-PON system

Fiber-to-the-home services based on wavelength-division-multiplexing passive optical network

This paper reviews the future directions of next generation passive optical networks. A discussion on standardized 10 Gb/s passive optical network (PON) systems is first presented. Next, new technologies that facilitate multiple access beyond 10 Gb/s time division multiple access (TDMA)-PONs will be reviewed, with particular focus on the motivation, key technologies, and deployment challenges. The wavelength division multiplexed (WDM) PON will be discussed and in combination with TDMA, the hybrid WDM/TDMA PON will be reviewed in the context of improving system reach, capacity, and user count. Next, discussions on complementary high-speed technologies that provide improved tolerance to system impairments, capacity, and spectral efficiency will be presented. These technologies include digital coherent detection, orthogonal frequency division multiple access (OFDMA), and optical code division multiple access (OCDMA).

/pdf/next-generation-broadband-access-networks-and-technologies-hinsjog43g.pdf

Next-Generation Broadband Access Networks and Technologies

We propose and demonstrate a novel wavelength-division-multiplexing (WDM) source employing an uncooled and unisolated Fabry-Perot semiconductor laser diode (F-P SLD). The output wavelength of F-P SLD is locked to the externally injected narrow-band amplified spontaneous emission (ASE). The measured side-mode suppression ratio of the wavelength-locked F-P SLD is larger than 29 dB, when the extinction ratio of the directly modulated light output is above 13 dB. We achieved error-free transmission of 155-Mb/s data over 120 km of nondispersion-shifted fiber. We also propose a cost-effective WDM passive optical network architecture based on the proposed light sources.

A low-cost WDM source with an ASE injected Fabry-Perot semiconductor laser

The present invention discloses a low-cost light source for optical transmission systems and optical networks based on wavelength-division multiplexing (WDM) technology. A light source in accordance with the present invention is implemented by externally injecting a narrow-band incoherent light into a Fabry-Perot laser diode (F-P LD). After injection of narrow-band incoherent light, the output of F-P LD becomes wavelength-selective rather than multi-mode and the output wavelength of F-P LD coincide with the peak wavelength of the injected incoherent light. Multi-channel WDM light sources according to the present invention can be implemented using a single broadband incoherent light source and plurality of F-P LDs. An optical transmission system for upstream signal transmission in an passive optical network using the light source according the present invention is also disclosed.

Low-cost wdm source with an incoherent light injected fabry-perot laser diode

The present invention relates to a wavelength-tunable light source whose output wavelength can be externally controlled and a wavelength-division multiplexed transmission system using the source. A wavelength-tunable light source in accordance with the present invention is constituted to be able to vary the output wavelength of a Fabry-Perot laser diode, that is wavelength-locked to an injected light, by controlling the wavelength of the injected light. A wavelength-tunable light source in accordance with the present invention provides comparatively large output power and excellent economic features. The present invention also presents a wavelength-division multiplexed transmission system using the wavelength-tunable light source.

Wavelength-tunable light source and wavelength-division multiplexed transmission system using the source

This invention relates to a multicast-capable optical cross-connect with layered modularity. Due to its layered modularity, this invention can be applied to many differently structured networks and provides easier maintenance than conventional optical cross-connects and efficient preparation for network evolution or node upgrade. By exploiting its simple elementary switches, multicast-capable optical cross-connect with layered modularity minimizes the switching time. For a given node, M input fiber ports supply multiplexed optical signals from other nodes in the network and m input fiber ports supply multiplexed optical signals generated from the node. M+m 1×M optical power splitters 311, 312, 313, 314, 315 distribute multiplexed input signals. A drop link module 331 selects signals to be dropped at the node where the optical cross-connect is installed. M transmission link modules 321, 322, 323 select signals to be transmitted to other nodes out of input signals.

Multicast-capable optical cross-connect with layered modularity

The present invention discloses a bi-directional add/drop multiplexer (BADM) and a bi-directional add/drop amplifier (BADA) module which add/drop wavelength-interleaved counter-propagating signals. The mid-stage device in the BADM and the BADA module is shared by the counter-propagating signals.

Hyun Deok Kim

Papers

A low-cost WDM source with an ASE injected Fabry-Perot semiconductor laser

Low-cost wdm source with an incoherent light injected fabry-perot laser diode

Wavelength-tunable light source and wavelength-division multiplexed transmission system using the source

Multicast-capable optical cross-connect with layered modularity

Bidirectional add/drop multiplexer and bidirectional add/drop amplifier module for wavelength interleaved bidirectional networks