Milestone-Proposal talk:Silica-based arrayed-waveguide grating (AWG) wavelength multi/demultiplexer

Advocates’ Checklist

1. Is proposal for an achievement rather than for a person? If the citation includes a person's name, have the proposers provided the required justification for inclusion of the person's name?
2. Was proposed achievement a significant advance rather than an incremental improvement to an existing technology?
3. Were there prior or contemporary achievements of a similar nature?
4. Has the achievement truly led to a functioning, useful, or marketable technology?
5. Is proposal adequately supported by significant references (minimum of five) such as patents, contemporary newspaper articles, journal articles, or citations to pages in scholarly books? At least one of the references from a peer-reviewed scholarly book or journal article. The full text of the material, not just the references, shall be present. If the supporting texts are copyright-encumbered and cannot be posted on the ETHW for intellectual property reasons, the proposers shall email a copy to the History Center so that it can be forwarded to the advocate. If the advocate does not consider the supporting references sufficient, the advocate may ask the proposer(s) for additional ones.
6. Are the scholarly references sufficiently recent?
7. Is proposed citation readable and understandable by the general public?
8. Does the proposed plaque site fulfill the requirements? Is the address complete? Are the GPS coordinates correct and in decimal format?
9. Is the proposal quality comparable to that of IEEE publications?
10. Scientific and technical units correct? (e.g. km, mm, hertz, etc.) Are acronyms correct and properly upperercased or lowercased?
11. Date formats correct as specified in Section 6 of Milestones Program Guidelines? https://ieeemilestones.ethw.org/Helpful_Hints_on_Citations,_Plaque_Locations

Reviewers’ Checklist

1. Is suggested wording of the Plaque Citation accurate?
2. Is evidence presented in the proposal of sufficient substance and accuracy to support the Plaque Citation?
3. Does proposed milestone represent a significant technical achievement?
4. Were there similar or competing achievements? If so, have the proposers adequately described these and their relationship to the achievement being proposed?

In answering the questions above, the History Committee asks that reviewers apply a similar level of rigor to that used to peer-review an article, or evaluate a research proposal. Some elaboration is desirable. Of course the Committee would welcome any additional observations that you may have regarding this proposal.

Submission and Approval Log

Submitted date: 1 February 2024
Advocate approval date:
History Committee approval date:
Board of Directors approval date:

Original Citation Title and Text -- Administrator4 (talk) 17:14, 3 April 2024 (UTC)

Silica-based arrayed-waveguide grating (AWG) wavelength multi/demultiplexer, 1992-1996

Nippon Telegraph and Telephone Corporation (NTT) invented the arrayed-waveguide grating (AWG) wavelength multi/demultiplexer using silica-based planar lightwave circuit technology in 1992, and developed high-performance and highly reliable AWGs first commercialized by NTT Electronics Corp. and Photonic Integration Research Inc. in 1996. The silica-based AWGs have accelerated the expansion of transmission capacity and are now widely used in high-capacity WDM optical fiber networks worldwide.

Reviewer #1 Comments -- Sselleri (talk) 09:21, 10 July 2024 (UTC)

I enclose here the comments I received by the Anonymous Reviewer#1.

I believe they are helpful and that proposers might want to add the comparison suggested in point #4 with FBG to their proposal.

Stefano (Advocate)

1. Is suggested wording of the Plaque Citation accurate? Yes, the wording is technologically accurate. It exactly indicates the invention and commercialization years of the silica planar lightwave circuit (PLC)-based arrayed-waveguide grating (AWG) by NTT, NEL, and PIRI. In addition, it adequately describes the impact of silica AWG contribution to the realization of high-capacity wavelength division multiplexing (WDM)-based photonic networks, which are widely used all around the world.

2. Is evidence presented in the proposal of sufficient substance and accuracy to support the Plaque Citation? The technical papers and patents are appropriately cited to show the importance and usefulness of the silica AWG [1]-[10]. They relate to not only the academically valuable basic configuration, characteristics, and designing of the silica AWG but also significant technology that further improved the AWG characteristics for the commercialization. The literatures [1], [3], [6], [8]-[10] clearly show the essence of the configuration and design method, and unique wavelength channel multi/demultiplexing characteristics regarding the silica AWG, and they have guided many subsequent researchers and engineers on the AWG. Other literatures [2], [4], [5], [7] proposed methods that eliminated polarization dependance of the silica AWG with polarization mode conversion. The polarization independence characteristics are indispensable for putting optical components to practical use in the photonic networks, and the proposed methods contributed considerably to the commercialization of the silica AWG. Some researchers of NTT surely received some prestigious awards [11]-[14] from an academic society, foundations, and the Japanese Minister of Education for their contribution to the invention and practical realization of the silica AWG.

3. Does proposed milestone represent a significant technical achievement? Yes, the silica AWG surely is a great achievement for our photonic network and device communities. The silica AWG is one of key components for the WDM photonic networks. The WDM is essential for increasing the capacity of the photonic networks and it employs tens or hundreds of wavelength channels. The optical multi/demultiplexer, which can deal with these large-scale wavelength channels and has substantial characteristics for the practical use, can only be achieved with the silica AWG. In addition, an optical add/drop multiplexer and an optical cross connect circuit can be realized by integrating the silica AWGs with optical switches. These devices are also widely utilized in the WDM photonic networks. I think that the silica AWG is the most successful photonic integrated circuit (PIC).

4. Were there similar or competing achievements? If so, have the proposers adequately described these and their relationship to the achievement being proposed? I think that a bulk-optic filter or a fiber Bragg grating (FBG)-based multi/demultiplexer was a competing achievement. The bulk-optic filter-based multi/demultiplexer requires many discrete components that are accurately aligned each other. Therefore, as mentioned by the proposers, the size of the bulk-optic filter-based multi/demultiplexer becomes large and its scalability is limited. In addition, the bulk-optic filter-based multi/demultiplexer does not have enough tolerance to the disturbance including the mechanical vibration. Although the proposers do not refer to the FBG-based multi/demultiplexer, it also has similar problems to the bulk-optic filter-based multi/demultiplexer. The FBG-based multi/demultiplexer needs as many pairs of FBGs and optical circulators (bulk-optic components) as the wavelength channels. The reflection wavelength of the FBG is sensitive to the temperature fluctuation. The proposers adequately and explicitly explained why these problems could be resolved with the silica AWG.

Other Comments The silica AWG is also applied to research areas other than optical communications. Examples include a spectroscopic sensor and a spectrum synthesizer for optical frequency combs. The silica AWG have also triggered the investigation of a semiconductor or a silicon waveguide-based multi/demultiplexer.

Re: Reviewer #1 Comments -- Ryoichi Kasahara (talk) 08:25, 17 July 2024 (UTC)

Thank you very much for useful comments by Reviewer #1. Following your suggestion, we would like to revise our proposal as follows. Added a comparison with FBG-type to the proposal.

What obstacles (technical, political, geographic) needed to be overcome? Before the early 1990s, only a bulk-optic-type and a fiber Bragg grating (FBG) -type components were available as wavelength multi/demultiplexer for WDM. The bulk-optic-type component is composed of many optical devices, such as optical lens, diffraction gratings, wavelength selective filters and mirrors, arranged in the optical path. It was necessary to align each component with high accuracy of sub-microns. Therefore, when wavelength channel scale is increased, the component configuration becomes complicated with many optical devices and the characteristic stability is deteriorated. The FBG type component is constituted by cascade-connecting many pairs of FBG filters and optical circulators as many as wavelength channels. This leads large device size and complicated precise wavelength adjustment when the channel scale is increased. For these reasons, the wavelength channel scale of the bulk-optic-type and FBG-type multi/demultiplexers was limited up to about 10 channels, which was insufficient to fully utilize the ultra-wide bandwidth of the optical fiber of 100 channels or more. It was expected to realize an integrated wavelength multi/demultiplexer based on optical waveguides with large wavelength channel scale, excellent characteristics, high reliability, mass productivity and low cost for practical use in the commercial optical transmission systems. The optical waveguide fabrication technology was also insufficient to realize a high-performance integrated wavelength multi/demultiplexer that required highly accurate optical phase control and optical polarization control for waveguided lights. The improvement of the high-precision and defect-less optical waveguide processing technology was required.