US 5,703,977 AGranted

Integrated optical mode converter

AssigneeKoninklijke PTT Nederland N.V.

InventorJ.o slashed.rgen Werngreen Pedersen

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Abstract

Integrated optical mode converter provided with a channel-shaped waveguide comprising a periodic concatenation of two wave-guiding subsections (P) and (Q) defined by a strip-shaped structure supported by a substrate. The waveguide profiles of the subsections (P) and (Q) are defined by two different partial strips, of which at least one is, but preferably both are, provided with a slot (S.sub.P, S.sub.Q) running in a longitudinal direction of the partial strip in question. The slots have been applied in such a manner that only the field distribution of one of the two guided modes involved in the mode conversion is affected. The resulting structure has increased conversion per interface; and lower attenuation in specific embodiments.

Claims31

Dependent claims

An integrated optical mode converter for converting a fraction of a signal component of a light signal propagating according to a first guided mode into a signal component propagating according to a second guided mode, with one of the two guided modes having an even order number and the other of the two guided modes having an odd order number, said integrated optical mode converter comprising:

a channel-shaped waveguide supported by a substrate, in which a periodic coupling takes place between the two guided modes of the light signal propagating in the waveguide,
said waveguide comprising an incoming wave-guiding section, an intermediary wave-guiding section and an outgoing wave-guiding section, and
said intermediary wave-guiding section comprising a periodic concatenation of two wave-guiding subsections per period, a length of the two wave-guiding subsections and a number of periods thereof being tuned to a desired fraction of conversion,
wherein at least one of the two wave-guiding subsections has a waveguide profile including a partial profile which has a deforming effect on a field distribution of one of the two guided modes and which does not substantially affect a field distribution of the other one of the two guided modes.

1 more element

A method for manufacturing a channel-shaped waveguide on a substrate comprising a package of layers having a light-conducting layer, said waveguide comprising a concatenation of wave-guiding sections alternating with a first and a second waveguide profile substantially defined by strip-shaped elements of a first and a second type, respectively, with the strip-shaped elements of at least one of the two types being provided with a slot running in a longitudinal direction thereof, the method comprising the following steps:

(a) applying to the substrate a first mask pattern of a first mask material, said first mask pattern comprising mask parts corresponding to the strip-shaped elements of the first and the second type, and to the slots running in the strip-shaped elements of at least one of the two types,
(b) etching, in a first etching operation, parts of the substrate not covered by any mask material,
(c) covering up mask parts of the first mask pattern, which correspond to the slots running in the strip-shaped elements of at least one of the two types, with a second mask pattern of a second material,
(d) etching, in a second etching operation, parts of the substrate not covered by any mask material.

1 more element

Dependencies are inferred from the claim text.